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Article
Peer-Review Record

Dependence of Fresh Grapes and Wine Taste Scores on the Origin of Varieties and Weather Conditions of the Harvest Year in the Northern Zone of Industrial Viticulture in Russia

Agronomy 2020, 10(10), 1613; https://doi.org/10.3390/agronomy10101613
by Liubov Yu. Novikova 1,* and Lyudmila G. Naumova 2
Reviewer 1:
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Agronomy 2020, 10(10), 1613; https://doi.org/10.3390/agronomy10101613
Submission received: 9 September 2020 / Revised: 12 October 2020 / Accepted: 19 October 2020 / Published: 21 October 2020
(This article belongs to the Special Issue Sustainable Viticulture and Vineyard Management on Table Grape)

Round 1

Reviewer 1 Report

I have provided detailed comments directly within the PDF version of the manuscript attached.

My main concern is that the paper it entitled and framed as a climate change study but it does not make sufficient efforts to actually earn that title.  The research is meaningful and interesting but is not framed properly.  This is not a climate change impact assessment is is an applied climatology paper that makes a meaningful contribution to the wine grape climatology literature.  This type of research is fundamental to the study of climate change impacts on grape and wine and should be framed that way.  This type of research paves the way for meaningful and informed impact assessments (as you appropriately allude to in the discussions section).  Furthermore, future research could use the models developed in this study to actually engage with the climate change question and apply the predicitive regression models to climate change scenarios and project impacts on grape and wine taste scores.

Finally, some discussion of the limitations of wine scores (how they are subjective) and also seems to be increasing over time regardless of warming trends, would be useful.  Also, figure 3 claims to verify the models but the authors do not discuss the failing of those models where certain years are modelled inversely to the observations.

I have given numerous suggestions for improving this paper and if the efforts are made, I believe it will make a solid contribution to the field of study.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer! We are very grateful to you for your critical reading of our text, we agree with all your comments, and we have tried to improve the quality of the text.

My main concern is that the paper it entitled and framed as a climate change study but it does not make sufficient efforts to actually earn that title.  The research is meaningful and interesting but is not framed properly.  This is not a climate change impact assessment it is an applied climatology paper that makes a meaningful contribution to the wine grape climatology literature.  This type of research is fundamental to the study of climate change impacts on grape and wine and should be framed that way.  This type of research paves the way for meaningful and informed impact assessments (as you appropriately allude to in the discussions section).  Furthermore, future research could use the models developed in this study to actually engage with the climate change question and apply the predicitive regression models to climate change scenarios and project impacts on grape and wine taste scores.

A: We tried to shift the focus of the manuscript from climate change.

We changed the title:

Lines 2-5: Dependence of Fresh Grapes and Wine Taste Scores on the Origin of Varieties and Weather Conditions of the Harvest Year in the Northern Zone of Industrial Viticulture in Russia

Finally, some discussion of the limitations of wine scores (how they are subjective) and also seems to be increasing over time regardless of warming trends, would be useful. 

A: We added in the introduction:

Lines 31-38: Expert analysis of the organoleptic properties of food products is the main tool for assessing consumer preferences [1,2]. Assessments of fresh berries taste and wine quality are made applying an expert method [3,4,5]. Expert assessments of the organoleptic quality of food products are an integral indicator of the interaction of chemical compounds that form the organoleptic properties of the product. There are models connecting the tasting evaluations with accurately measured quantitative indicators [3,6,4,7], however, the measured scores of grape quality are indirect [8], the same “desired quality” can correspond to strikingly different compositional models [7], and the expert procedure remains the key to determining consumer preferences [2].

 

A: We added to the discussion:

Lines 284-297: Expert tasting is the main tool for evaluating the taste qualities of test samples by analyzing their organoleptic properties. An expert judgment contains a significant subjective component, for example, the results of tasting are influenced by the composition of experts, their number, the physiological characteristics of each expert at the time of tasting, subjectivity in the perception of organoleptic properties, unbalanced wines, etc. [2]. Despite its subjectivity, expert tasting assessment remains the main method for determining consumer preferences [3,4,5]. At the same time, as our experience shows, even subjective qualities determined by expert methods show dependence on the meteorological conditions of the year. For example, elegance (nice and attractive appearance) depends on the weather conditions of a particular year; the drier the year, the more beautiful the berries are in pink or white varieties, as they turn amber color. With a large amount of precipitation, the pulp of some table varieties becomes more liquid, and the variety will be less transportable. The tastes could change from year to year, additionally building up the error of estimates. However, there is no reason to suspect that the changes in taste over 39 years have had any definite trend that would go beyond an accidental error.

 

Lines 335-338: Despite the fact that wine tasting ratings did not have a reliable trend, there was a slight increase in it over the years. The model's climate-related forecast is also positive. All this suggests the observed weak trend in wine scores is related to decreasing precipitation, however it is too small against the background of year-to-year fluctuations and will become reliable over a longer observation period.

 

Also, figure 3 claims to verify the models but the authors do not discuss the failing of those models where certain years are modelled inversely to the observations.

A: We added the following text:

Lines 254-276: The models explain 50 and 53% of the variability, i.e. half or more of it, what makes it possible to predict the overall trend of tasting scores. But the remaining 50 and 47%, respectively, are caused by other random factors, such as extreme weather events, atypical seasonal course of temperature and precipitation, diseases, conditions of the previous growing season, and so on.

The largest errors in GS model were in 1992, 1993 and 2017, when actual values were 0.27-0.34 points higher than model. These years were characterized by a long period with temperatures favorable for vegetative growth of 15-20°C up to 36-40 days vs. the average perennial 18 days, which, under favorable conditions for further vegetation, created the basis for high quality of berries of table varieties, despite the fact that the average summer temperature was not very high.

In 1982, 1985, and 1995, the actual GS values turned out to be 0.27-0.34 points lower than the forecasted ones. Unfavorable winter conditions were observed in 1982 and 1985, when the temperature in February was -8.8 °C and 9.7 °C vs. the long-term average of -3 °C, and a significant number of days had temperatures below -15 °C (14 and 31 days vs. the long-term average of 9 days). These circumstances led to a reduced quality of berries in the summer with a heat availability below average (the average temperature above 15 °C was 19.2 °C and 20.9 °C vs. the norm of 21.5 °C).

The calculated scores of wine quality reflected the extremely low WS values in the humid 2004 and 2006. The largest errors of the wine quality model were observed in 2015 and 2014, when the calculated values exceeded the actual ones by 0.09 and 0.05 points, respectively. This is associated with extremely low precipitation during the period of berry formation: the total of 12 and 15 mm of precipitation, respectively, fell out in July-August. In 2002 and 2005, on the contrary, the actual values were higher than the calculated ones by 0.05-0.06 points, which is associated with the low value of the average number of clusters per productive shoot (1.37 and 1.42 vs. the long-term average of 1.54) in these years.


In peer-review.v1.pdf

Comments on the text:

Lines 12-13 – “Abstract: Climate change affects all characteristics of grapes, including the most important ones – the taste of fresh berries and wine.”

R: seems a bit presumptuous to conclude in your opening statement that berry/wine taste is the most important characteristic of wine grapes (others may argue yield or price are more important than taste).

A: We change to:

Lines 14-15: Abstract: Climate change affects all characteristics of grapes, including the taste of fresh berries and wine.”

Line 23-24 – “Thus, the observed climate warming is favorable for viticulture in the northern zone of industrial viticulture in Russia.”

contradictions seem evident within the abstract, all stemming from the opening statement that berry/wine taste is the most important factor affected by climate change.

A: To support the statement, we added trend information for other economically important traits to the Discussion:

Lines 340-346: The previously performed analysis of trends in groups of varieties of various interspecific origin and type of use at the Don Ampelographic Collection showed [16] that varieties do not differ in trends of the long-term dynamics of most indicators. All groups demonstrated a decrease in the ripening time for 2 days per 10 years, an increase in yield for 1 kg per bush per 10 years and sugar content for 2 g 100 cm-3 per 10 years, a decrease in acidity of 1 g dm-3, which corresponds to the trends observed in other countries [66].

Line 44 – “Temperature, precipitation, solar radiation”

change “,” to «and».

A: Thanks, we changed (Line 54).

Line 55 – « Large amounts of precipitation increase the yield and lower sugar content [22,30], but severe, long water deficits diminish must quality [15,32]. »

R: most?

А: We added:

Lines 64-67: but severe long-term water deficiency adversely affects the plant as a whole, negatively affects photosynthetic activity, causes leaf abscission and collapsing the ripening process, which reduces the quality of must and wine [11,25,42].

Lines 56-58 - “The wine quality increases with the growth of temperature during ripening to 35-40°С and decreases with the increasing rainfall [1,22,25].”

R: English writing not clear here

A: We modified the text as follows:

Lines 68-69: The wine quality is higher in years with a higher temperature during ripening and lower in humid years [9,34,38].

Lines 61-63: “The purpose of this study was to identify climate-related dependencies of fresh grapes taste  scores (GS) and wine taste scores (WS) in recent decades in the northern zone of industrial viticulture in Russia in recent decades.»

R: no where in this purpose statement do you mention observed or projected climate changes, although climate change appears in the title.  Therefore, the question remains: is this just an APPLIED CLIMATOLOGY paper or is it truly a CLIMATE CHANGE IMPACT ASSESSMENT?

A: We matched the stated objective of the article with the modified title:

Lines 63-75: The purpose of this study was to reveal the dependence of fresh grapes taste scores (GS) and wine taste scores (WS) on the origin of the varieties and weather conditions of the harvest year in the northern zone of industrial viticulture in Russia.

Lines 128-129 – “HTC, the ratio of the total precipitation to the sum of 128 temperatures divided by 10)”

R: some form of reference for HTC is required, seems very similar to the de Martonne Aridity Index, but still, a source is required.

A: We made the recommended addition:

Lines 156-157: Selyaninov’s hydrothermal coefficient (HTC, the ratio of the total precipitation to the sum of temperatures divided by 10 [55,56])…

Line 137-139 – “significant increase in ΣT10 for 174.0°С per 10 years was observed (the significance level of the trend is p < 0.001), while the amount of precipitation did not change significantly, having reduced for 22.3 mm per 10 years (p = 0.082). Since 1990, warming has been going more intensively, the ΣT10 increase reached 210.0°С per 10 years (p < 0.001), and precipitation kept decreasing at a rate of 54.4 mm per 10 years (p = 0.008).“

R: this is really the only place where "climate change" is reported, and it is only done so briefly while also being within the methods section... leading me to conclude that this is not a climate change study, but rather a wine grape climatology paper (which is fine, but it needs to be properly titled and introduced that way).

A: We agree.

R: the sum of average temperature above a base of ten degrees Celsius is by definition the Winkler Index and is referred to as growing degree days within the wine-grape climatology literature.

A: We added:

Lines 155-156: the sum of daily temperatures, degree-days above these thresholds,….

Lines 143-144 - “The score has no strong correlations with any of the 12 studied agrobiological characteristic (Table 2).”

R: what is the basis for this distinction? A Pearson's r value of 0.63 would likely have a p value <0.001 so why is this considered medium rather than strong? you would need to define such a theoretical classification of r values first (plus you don't make the same distinction when reporting negative correlations).

A: We added:

Lines 175-176: The score has no strong correlations, exceeding 0.7 in modulus, with any of the 12 studied agrobiological characteristic

Line 155 - Thus, a larger berry mass and productivity reduce wine taste scores.

R: Shoot.

A: We added:

Line 189: shoot productivity.

Line 171 “The group of ripening did not have a significant effect on GS (р = 0.332), or WS (р = 0.784).”

R: where does this sentence belong? it cannot be a stand alone paragraph.  should it not be moved up to the end of the previous paragraph?

A: We moved it up, Line 202.

However, we believe that this sentence should be a separate paragraph, since it is devoted to the influence of the "ripening time" factor, in contrast to the "origin of the variety" factor, to which the previous paragraph is devoted.

Line 173 – “In 1981-2019, the average GS for the sample…”

R: use "from" when referring to the study time frame and use "in" when referring to the study location.

A: Thanks, we corrected, Line 226

Lines 179-180: “Figure 2. Dynamics of the average taste scores of (a) fresh grapes, (b) wine. Designations: solid 179 line – actual data; dotted line – calculated linear trend.”

R: if a linear trend was calculated, why is it not reported? why is a ten year beta recorded instead? why not multiply the beta value by the number of years in the time series to indicate the magnitude of change over the study period (according to the linear trend).  Also, what is the p value for? the actual linear trend line (y=mx+b) or for the aggregated ten-year beta value?

A: We made the following addition to Methods:

Lines 147-150: To calculate the trends, the equations of the studied trait regression dependence on the year number were built; the significance of the obtained regression coefficient was estimated. For convenience, trend values were multiplied by 10 due to small values of some trends, i.e., they were expressed as the rate of change per decade [54].

Line 185:

R: at what level? P<0.05 or P<0.01|?

A: We added significance levels to the correlation coefficients, Lines 215-224.

Lines 243-246 – “the importance of the characteristics of the periods with temperature above these limits. Such a generalized characteristics have an advantage for constructing models under the climate change conditions compared with monthly, as they are not tied to a specific month and remain relevant when phenological dates get shifted.”

R: English writing is not clear here.

A: Thanks, you are right. We tried to improve:

Lines 332-334: Such generalized agroclimatic indices are convenient for creating regression models under climate change conditions, because dependencies remain true when phenological events are shifted to other months.

Line 253

R: these last two discussion paragraphs have clear implications for climate change impact assessment (which is good), but again, this study itself it not a climate change impact assessment; but rather, an example of applied climatology research (more specifically, the agro-climatology of grapes).

A: We agree, we hope we managed to shift the stress from climate change to investigation of the dependence of taste scores.

Line 255 – The observed climate warming is favorable for viticulture in the northern zone of industrial…

R: this conclusion is simply restating what has already been said in the discussion and also one sentence does not form a paragraph and certainly does not comprise a section (personally, I would re-title section 4 as discussion and conclusions).

A: The Title was changed, and the Conclusions were changed accordingly:

Lines 353-366: The analysis of grape varieties of the Ya.I. Potapenko Don Ampelographic Collection showed that taste scores of viticulture products depended on the interspecies origin of the variety, the lowest scores has the group of V. vinifera × V. labrusca hybrids.

In recent decades, the average taste scores of fresh grapes have increased in groups of varieties of various interspecies origin, and the wine scores have not changed.

An analysis of the relationship between taste scores of fresh berries and wines with agrometeorological conditions showed that the year-to-year variability of the former is determined by 50 or more percent by the weather conditions of the harvest year. In the conditions of the northern zone of industrial viticulture in Russia, the weather factor limiting the quality of table grapes is the lack of heat, namely, of temperatures above 15°C. The quality of the wine decreases in years with excessive midsummer rainfall, namely in the period with temperatures above 20°C.

The observed climate warming leads to an increase in the sugar content, in yield and in taste scores for the quality of fresh berries, i.e., is favorable for grapevine cultivation in the northern zone of industrial viticulture in Russia.

Line 267 – References

there are two recent climate change impact assessments on grape and wine in Canada that may be worth citing in this paper's discussion, especially since viticulture in Canada is very similar to that is Russia, given the similar climate conditions, limitations and risks (it would also give the paper much more on a international scope - as it is currently very much so limited to the Russian literature).

 

Roy, P., Grenier, P., Barriault, E., Logan, T., Blondlot, A., Bourgeois, G., & Chaumont, D. (2017). Probabilistic climate change scenarios for viticultural potential in Québec. Climatic Change, 143(1-2), 43-58. doi:10.1007/s10584-017-1960-x

 

Hewer, M., & Brunette, M. (2020). Climate Change Impact Assessment on Grape and Wine for Ontario, Canada’s Appellations of Origin. Regional Environmental Change, 20(3), 1-15. doi:10.1007/s10113-020-01673-y

 

A: Thank you very much, we enjoyed reading them, we added them to the References, Lines 412, 546.

Author Response File: Author Response.pdf

Reviewer 2 Report

agronomy-944096

The Influence of Climate Change on the Taste Scores of Fresh Grapes and Wine in the Northern Zone of Industrial Viticulture in Russia

 

  1. The paper is based on a methodology which is not reliable enough to demonstrate the effect of climate changes on grapes and wines characteristics.

The paper is trying to establish a relationship between sensory analyses scores for table grapes and  wines and the climatic changes recorded during the past 38 years.

However, sensory analyses scores alone are too subjective parameters, with too large measurement errors to be reliable enough to directly relate to small and precise changes observed in climate. The tasting scores determined were fluctuating between 6.6-8.5 for table grapes and between 8.2 and 8.8 on a scale of 0 to 10, which is a very narrow range to really show differences among samples. Besides, the scores for the evaluation of grapes may differ largely not only due to the vintage (climate), but also due to the variety genetic traits and even the time of actual harvest, the latter having a much more significant influence than any observed climate change. And, there is no information in the paper about harvest time or any attempt to exclude the influence of this factor.

Moreover, the sensory analysis performed is not described in sufficient detail to determine if it can be considered standardized. For the scoring of fresh grapes (lines 101-104) some of the evaluated attributes are very subjective, such as: “elegance 0.5-1.0 points”, “size 0.1-0.5”, “density 0.5-1.0”, “transportability 0.5-1.0”; “skin character 0.1-0.5”, “separability, quantity and size of the seed 0.1-0.5”. These attributes cannot be directly corelated to climate change, as they cannot be reliably and consistently scored by the judges in the absence of control samples. For the wine evaluation some of the descriptors are even more subjective, such as (line 105-106) “taste 1.0-5.0” or “matching the type of wine 0.2-1.0”. These scores depend very much on the degree of experience of a taster regarding the particular grape variety/wine evaluated. The differences in scores may be especially large because the evaluated grapes come not only from Vitis vinifera, but also from other species or crossings. Some of the evaluated varieties are so singular or so different than the usual Vitis vinifera that very few specialists may know or appreciate correctly their taste to be able to award an accurate score on such a large scale as “taste 1.0-5.0” out of 10.

Even more disturbing is the fact that the sensory scores are reported for large periods of time (1981-2019, 38 years), which clearly means that the sensory panel has changed multiple times, affecting very much the consistency/reliability of the results. There is no reference to the specialists involved in the sensory scoring and their training.

Under these conditions it is no wonder that the final result was that the wine taste scores did not have a reliable trend. Even more, for wines, the winemaking technologies can differ significantly from one variety to another, from one year to another, from one style of vinification to another, which means that this kind of comparison is meaningless. There is no information about the samples of wines evaluated (technology, grape and wine parameters and so on).

Furthermore, although mentioned (lines 91-95), the ripening groups defined were not actually used anywhere in the paper.

 

  1. The data analysis is weak and a lot of possibly good information is lost by averaging the results instead of using multivariate statistics

In lines 118-122 it is explained that the data analysis is based on the average of taste scores for all 232 varieties or for groups of varieties with a certain genetic lineage. In authors’ opinion and according to some other authors cited in the paper, “the “average variety” data have less random error and a greater dependence on weather conditions”. In the reviewer's opinion the sensory evaluation score is not detailed enough to reveal minute differences and, in case they actually do for some varieties, these differences are entirely lost when all data are included into an “average variety”.

Based on this methodology, only moderate correlations were found and only for a few parameters measured (lines 144-146 and Table 2: “berry crushing force (r = 0.63), berry mass (r = 0.62), cluster mass (r = 0.54) and the force of berry 145 separation from the pedicel (r = 0.48).”). It is to be noted that the few parameters that have a tendency to correlate to climate change are parameters determined with more precise physical methods than the sensory analysis mentioned in the title.

Even though it is clear from the scientific literature that the main influence of the climate change is observable at the level of sugar and acidity concentrations, due to the averaging applied in this paper, for these parameters no correlation was found (r=-0.23 and r=0.06, respectively).

From figure 1 (lines 167-170) one can clearly see that the average sensory scores on grape groups or wines have large errors (values are spread on large ranges) and no significant difference can be observed among groups.

Considering that the sensory scores are out of 10, with a range from 7.0 to 8.4 for grapes and 8.44-8.72 for wines, the figure 2 (lines 178-180) does not demonstrate any statistically significant increase.

  1. The results and discussion sections are weak, due to methodology applied

The authors apply several statistical analyses on the data they collected, but since the methodology of obtaining those data has low consistency and accuracy, the results obtained have low relevance.

  1. The conclusion section is too brief and basically says that climate warming is an opportunity for viticulture of the region, a fact that is not fully supported by the results. To demonstrate favourability, more parameters should be discussed.
  1. Bibliography is comprehensive, but can benefit from some more recent additions, such as some titles from the OIV Congress 2019 held in Geneve, which had a special section on Viticulture and Climate Change (http://www.oiv.int/public/medias/6976/oiv-2019-book-of-abstracts-42nd-world-congress-of-vine-and-w.pdf)

With all things considered, in spite of the tremendous amount of work carried out to collect data over 38 years, due to the weak methodology applied, especially regarding the sensory analysis evaluations, the paper is not publishable in this form.

 

In case the paper will be some day improved by including some more accurate analyses or by selecting some specific varieties or groups to discuss more comprehensively, we include hereafter some minor observations regarding the style and terms:

Industrial viticulture is a term that is used in certain countries (meaning probably organized or large-scale viticulture?), but with no specific meaning for the rest of the countries. As we speak of climate change the effect should be similar on any type of viticulture, thus we suggest removing industrial from the title and the rest of the text.

Fresh grapes in this paper is equivalent to table grapes, as only table grapes were subjected to sensory analysis fresh, while the wine grapes were not tasted, but turned into wines and only wines analysed sensorially. The “fresh grapes” may be better replaced by “table grapes” in the title and the rest of the text.

Lines 29-30 are implying that climate change is most important in viticulture and winemaking, a fact that was not demonstrated anywhere in the paper. Climate change is important in many sectors, and one cannot say that nowhere is it more important than in viticulture and winemaking, especially when the results show in the end that wine scores were not consistently affected by the climate change.

Lines 31-33 refer to changes in climate and effects in viticulture observed in other countries, but do not give any reference for this. More references could be introduced here from the international research, including:

“Georgeta Mihaela Bucur, George Cojocaru, Arina Oana Antoce, 2019, The climate change influences and trends on the grapevine growing in Southern Romania: A long-term study, 42nd World Congress of Vine and Wine, BIO Web of Conferences 15, 01008 (2019), pp. 1-6, ISBN 9781510897663, https://doi.org/10.1051/bioconf/20191501008”

Some other papers, presented at OIV Congress in 2019 in Geneva (42nd WORLD CONGRESS OF VINE AND WINE, "Preservation and innovation: Expectations at the environmental, economic and social level", Book of Abstracts, ISBN: 978 285 038 0105, July 15th – 19rd 2019, Geneva, Switzerland) have only been published as abstracts:

Alyssa Ryan, Kelli M Archie, John Overton, Ralph Chapman, Climate change planning in viticulture: New Zealand winegrowers’ perspectives on adaptation

Rauf Asadullayev, Khadija Mammadova, Teymur Musayev, 2019, Influence of the local climatic specifics on storage ability of grape varieties in the conditions of Apsheron peninsula

Valentin Comte, Vivian Zufferey, Johannes Rösti, Pierluigi Calanca, Martine Rebetez, 2019, adaptation strategies of a cold climate vineyard to climate change, the case of the Neuchâtel region in Switzerland

Etienne Neethling, Cécile Coulon-Leroy, Etienne Goulet, Philippe Chrétien, Hervé Quénol, 2019, Effect of climate variations on grape composition and sensory profile: case of Chenin Blanc in the middle Loire Valley

Lines 36-38 contains a phrase with an unclear meaning. Please rephrase and explain what can be done scientifically to counteract the effects of climate change.

Lines 54-55 - “but severe, long water deficits diminish must quality”. Authors should explain in what way the quality of must is affected, what parameters suffer detrimental changes.

Lines 84, Table 1 and elsewhere in the paper: consider replacing the term “universal variety” with a clearer term, such as "variety with mixed uses” if this actually refers to the fact that these varieties have both wine and table grape traits.

In line 87 authors say “From the point of view of interspecies origin…”, but later in the phrase it becomes apparent that not all are "interspecies" since 139 varieties are V. vinifera L.”

In lines 91-94, the ripening groups are defined in accordance to some number of days (for example, “ultra-early - up to 105 days”), but for the reader the meaning is not clear. It may probably be “days of vegetation”, or “a vegetation period of x days”.

In line 114 the expression “Mean perennial values of all characters” is not at all clear and should be explained or redefined.

Author Response

Dear Reviewer! Thank you for the detailed analysis of our work. Thanks to you, we have significantly improved the description of methods and discussion.

The expert procedure, which is carried out by specialists of Ya.I. Potapenko All-Russian Research Institute for Viticulture and Winemaking in accordance with state standards adopted in our country, does not have the task to describe the taste of berries or wine, its task is to determine the consumer value of berries or wine varieties in a particular year, when expert does not know the name of the variety.

Our work is based on a statistical approach. We do not have the task to analyze individual varieties.

The paper is based on a methodology which is not reliable enough to demonstrate the effect of climate changes on grapes and wines characteristics.

The paper is trying to establish a relationship between sensory analyses scores for table grapes and  wines and the climatic changes recorded during the past 38 years.

However, sensory analyses scores alone are too subjective parameters, with too large measurement errors to be reliable enough to directly relate to small and precise changes observed in climate.

A: This statement needs statistical proof.

The fact that we managed to cope with so complex indicators and identify reliable relationships against the background of numerous sources of errors, we consider as an advantage of our work; this is its novelty and significance. In the cases where the regularity was small compared to random error, the relationship with weather and climate has not been proven, for instance, for wine ratings.

The tasting scores determined were fluctuating between 6.6-8.5 for table grapes and between 8.2 and 8.8 on a scale of 0 to 10, which is a very narrow range to really show differences among samples.

A: This statement needs statistical proof.

Information added:

Lines 31-38: Expert analysis of the organoleptic properties of food products is the main tool for assessing consumer preferences [1,2]. Assessments of fresh berries taste and wine quality are made applying an expert method [3,4,5). Expert assessments of the organoleptic quality of food products are an integral indicator of the interaction of chemical compounds that form the organoleptic properties of the product. There are models connecting the tasting evaluations with accurately measured quantitative indicators [3,6,4,7], however, the measured scores of grape quality are indirect [8], the same “desired quality” can correspond to strikingly different compositional models [7], and the expert procedure remains the key to determining consumer preferences [2].

We also added:

Lines 184-187: The small variability in WS is possibly associated with the harvesting of wine varieties when the berries reach certain conditions necessary for processing into a certain type of wine (in this particular case, dry table wine).

Besides, the scores for the evaluation of grapes may differ largely not only due to the vintage (climate), but also due to the variety genetic traits and even the time of actual harvest, the latter having a much more significant influence than any observed climate change. And, there is no information in the paper about harvest time or any attempt to exclude the influence of this factor.

A: The relationship with the genetic characteristics of a variety was investigated in a statistical sense, namely with the groups of different interspecific origin. The analysis of individual characteristics of varieties was beyond the scope of the statistical approach, which had been chosen as the analytical method for this article.

Information added:

Lines 208-214: The year-to-year GS variability had a significantly positive correlation with cluster weight (r=0.53 p<0.001), yield per bush (r=0.45, p=0.004), shoot productivity (r=0.39 p=0.014), and a negative correlation with acidity (r=-0.45, p=0.004).

The year-to-year WS variability was not significantly associated with any other indicator. The highest relation was with sugar content (r=0.36), but it was not significant (p=0.118). Other relations were weak and insignificant, in particular, there was no relation with the ripening period duration (r=0.03, p=0.902).

Moreover, the sensory analysis performed is not described in sufficient detail to determine if it can be considered standardized. For the scoring of fresh grapes (lines 101-104) some of the evaluated attributes are very subjective, such as: “elegance 0.5-1.0 points”, “size 0.1-0.5”, “density 0.5-1.0”, “transportability 0.5-1.0”; “skin character 0.1-0.5”, “separability, quantity and size of the seed 0.1-0.5”. These attributes cannot be directly corelated to climate change, as they cannot be reliably and consistently scored by the judges in the absence of control samples.

A: We added:

Lines 116-119: Control samples are always present at tasting sessions of both fresh grapes and wine. The varieties included in the Register of Breeding Achievements Permitted for Use (in the Russian Federation) are taken as control varieties.

We added:

Lines 114-120: Scoring of samples of fresh berries and wine was carried out at closed scientific tasting sessions by members of tasting commissions, approved by order of the Director of The Institute from among specialists of the Institute, in accordance with State Standard GOST 32051-2013 [49]. Control samples are always present at tasting sessions of both fresh grapes and wine. The varieties included in the Register of Breeding Achievements Permitted for Use (in the Russian Federation) are taken as control varieties. The name of the variety is disclosed after all members of the tasting committee have given their marks.

We added to discussion:

Lines 284-294: Expert tasting is the main tool for evaluating the taste qualities of test samples by analyzing their organoleptic properties. An expert judgment contains a significant subjective component, for example, the results of tasting are influenced by the composition of experts, their number, the physiological characteristics of each expert at the time of tasting, subjectivity in the perception of organoleptic properties, unbalanced wines, etc. [2]. Despite its subjectivity, expert tasting assessment remains the main method for determining consumer preferences [3,4,5]. At the same time, as our experience shows, even subjective qualities determined by expert methods show dependence on the meteorological conditions of the year. For example, elegance (nice and attractive appearance) depends on the weather conditions of a particular year; the drier the year, the more beautiful the berries are in pink or white varieties, as they turn amber color. With a large amount of precipitation, the pulp of some table varieties becomes more liquid, and the variety will be less transportable.

For the wine evaluation some of the descriptors are even more subjective, such as (line 105-106) “taste 1.0-5.0” or “matching the type of wine 0.2-1.0”. These scores depend very much on the degree of experience of a taster regarding the particular grape variety/wine evaluated. The differences in scores may be especially large because the evaluated grapes come not only from Vitis vinifera, but also from other species or crossings. Some of the evaluated varieties are so singular or so different than the usual Vitis vinifera that very few specialists may know or appreciate correctly their taste to be able to award an accurate score on such a large scale as “taste 1.0-5.0” out of 10.

A: we added:

Lines 114-116: Scoring of samples of fresh berries and wine was carried out at closed scientific tasting sessions by members of tasting commissions, approved by the order of the Director of The Institute from the Institute's specialists, in accordance with State Standard GOST 32051-2013.

Lines 119-120: The name of the variety is disclosed after all members of the tasting committee have given their marks.

Even more disturbing is the fact that the sensory scores are reported for large periods of time (1981-2019, 38 years), which clearly means that the sensory panel has changed multiple times, affecting very much the consistency/reliability of the results. There is no reference to the specialists involved in the sensory scoring and their training.

A: we added to discussion:

Lines 294-297: The tastes could change from year to year, additionally building up the error of estimates. However, there is no reason to suspect that the changes in taste over 39 years have had any definite trend that would go beyond an accidental error.

Under these conditions it is no wonder that the final result was that the wine taste scores did not have a reliable trend. Even more, for wines, the winemaking technologies can differ significantly from one variety to another, from one year to another, from one style of vinification to another, which means that this kind of comparison is meaningless. There is no information about the samples of wines evaluated (technology, grape and wine parameters and so on).

 A: we added:

Lines 110-113: The varietal dry table wines were produced by micro-winemaking in the laboratory of winemaking technology of the Ya.I. Potapenko All-Russian Research Institute for Viticulture and Winemaking, under micro-wine production conditions, according to a unified method in compliance with regulatory documents [46-48].

Furthermore, although mentioned (lines 91-95), the ripening groups defined were not actually used anywhere in the paper.

A: the assessment of ripening groups is given in Line 202: «The group of ripening did not have a significant effect on GS (р = 0.332), or WS (р = 0.784)».

We moved this passage higher (Line 171) in the text to make it more noticeable.

  1. The data analysis is weak and a lot of possibly good information is lost by averaging the results instead of using multivariate statistics

In lines 118-122 it is explained that the data analysis is based on the average of taste scores for all 232 varieties or for groups of varieties with a certain genetic lineage. In authors’ opinion and according to some other authors cited in the paper, “the “average variety” data have less random error and a greater dependence on weather conditions”. In the reviewer's opinion the sensory evaluation score is not detailed enough to reveal minute differences and, in case they actually do for some varieties, these differences are entirely lost when all data are included into an “average variety”.

A: we added:

Lines 229-234: To check the trend of the "average variety" the taste score trends for the varieties with the longest observation period were calculated. The trend of GS for Moldova variety was 0.20 points per 10 years within 28 years of observations (p=0.001), and the trend of WS for Krasnostop zolotovsky variety was insignificant (0.01 points per 10 years) within 16 years (p=0.282). Trends in these varieties are comparable with that for the “average variety”.

Based on this methodology, only moderate correlations were found and only for a few parameters measured (lines 144-146 and Table 2: “berry crushing force (r = 0.63), berry mass (r = 0.62), cluster mass (r = 0.54) and the force of berry 145 separation from the pedicel (r = 0.48).”). It is to be noted that the few parameters that have a tendency to correlate to climate change are parameters determined with more precise physical methods than the sensory analysis mentioned in the title. Even though it is clear from the scientific literature that the main influence of the climate change is observable at the level of sugar and acidity concentrations, due to the averaging applied in this paper, for these parameters no correlation was found (r=-0.23 and r=0.06, respectively).

A: The correlations of the listed taste scores of varieties are not with the climate, but with other variables.

We added the supplement:

Table S2. The correlation coefficients between the tasting scores of fresh berries and wine of the "average variety" with agrometeorological indicators.

We added:

Lines 339-346: In recent decades, the average GS have increased at in groups of varieties of various interspecies origin for 0.15 points per 10 years, and the WS have not changed. The previously performed analysis of trends in groups of varieties of various interspecific origin and type of use at the Don Ampelographic Collection showed [16] that varieties do not differ in trends of the long-term dynamics of most indicators. All groups demonstrated a decrease in the ripening time for 2 days per 10 years, an increase in yield for 1 kg per bush per 10 years and sugar content for 2 g 100 cm-3 per 10 years, a decrease in acidity of 1 g dm-3, which corresponds to the trends observed in other countries [66].

From figure 1 (lines 167-170) one can clearly see that the average sensory scores on grape groups or wines have large errors (values are spread on large ranges) and no significant difference can be observed among groups.

A: This statement has to be proved. Fig. 1 shows the minimum, maximum values and quartiles. It is rather difficult to compare reliability on their basis. All the initial data are presented in the Supplement Table S1, so anyone can check the reliability of the differences between the groups.

Considering that the sensory scores are out of 10, with a range from 7.0 to 8.4 for grapes and 8.44-8.72 for wines, the figure 2 (lines 178-180) does not demonstrate any statistically significant increase.

Учитывая, что сенсорные оценки находятся вне 10, с диапазоном от 7,0 до 8,4 для винограда и 8,44-8,72 для вин, Рисунок 2 (строки 178-180) не демонстрирует какого-либо статистически значимого увеличения.

A: This statement needs statistical proof.

  1. The results and discussion sections are weak, due to methodology applied

The authors apply several statistical analyses on the data they collected, but since the methodology of obtaining those data has low consistency and accuracy, the results obtained have low relevance.

A: We propose to separate claims to the initial data and to the methodology applied.

Here we do not find a claim to the methods. We obtained the initial data using standard, regulated methods, and consider have the right to exist.

  1. The conclusion section is too brief and basically says that climate warming is an opportunity for viticulture of the region, a fact that is not fully supported by the results. To demonstrate favourability, more parameters should be discussed.

Раздел выводов слишком краток и в основном говорит о том, что потепление климата - это возможность для виноградарства региона, факт, который не полностью подтверждается результатами. Чтобы продемонстрировать благоприятность, следует обсудить больше параметров.

А: we added to the discussion:

Lines 339-346: In recent decades, the average GS have increased at in groups of varieties of various interspecies origin for 0.15 points per 10 years, and the WS have not changed. The previously performed analysis of trends in groups of varieties of various interspecific origin and type of use at the Don Ampelographic Collection showed (Novikova, Naumova, 2019) that varieties do not differ in trends of the long-term dynamics of most indicators. All groups demonstrated a decrease in the ripening time for 2 days per 10 years, an increase in yield for 1 kg per bush per 10 years and sugar content for 2 g 100 cm-3 per 10 years, a decrease in acidity of 1 g dm-3, which corresponds to the trends observed in other countries [66].

The Conclusions changed as follows:

Lines 353-366: The analysis of grape varieties of the Ya.I. Potapenko Don Ampelographic Collection showed that taste scores of viticulture products depended on the interspecies origin of the variety, the lowest scores has the group of V. vinifera × V. labrusca hybrids.

In recent decades, the average taste scores of fresh grapes have increased in groups of varieties of various interspecies origin, and the wine scores have not changed.

An analysis of the relationship between taste scores of fresh berries and wines with agrometeorological conditions showed that the year-to-year variability of the former is determined by 50 or more percent by the weather conditions of the harvest year. In the conditions of the northern zone of industrial viticulture in Russia, the weather factor limiting the quality of table grapes is the lack of heat, namely, of temperatures above 15°C. The quality of the wine decreases in years with excessive midsummer rainfall, namely in the period with temperatures above 20°C.

The observed climate warming leads to an increase in the sugar content, in yield and in taste scores for the quality of fresh berries, i.e., is favorable for grapevine cultivation in the northern zone of industrial viticulture in Russia.

Bibliography is comprehensive, but can benefit from some more recent additions, such as some titles from the OIV Congress 2019 held in Geneve, which had a special section on Viticulture and Climate Change (http://www.oiv.int/public/medias/6976/oiv-2019-book-of-abstracts-42nd-world-congress-of-vine-and-w.pdf)

А: thank you, we have increased the list of references.

With all things considered, in spite of the tremendous amount of work carried out to collect data over 38 years, due to the weak methodology applied, especially regarding the sensory analysis evaluations, the paper is not publishable in this form.

A: we believe that the analysis of expert tastings has a right to exist.

In case the paper will be some day improved by including some more accurate analyses or by selecting some specific varieties or groups to discuss more comprehensively, we include hereafter some minor observations regarding the style and terms:

Industrial viticulture is a term that is used in certain countries (meaning probably organized or large-scale viticulture?), but with no specific meaning for the rest of the countries. As we speak of climate change the effect should be similar on any type of viticulture, thus we suggest removing industrial from the title and the rest of the text.

А: In Russia, the zone of amateur grapes cultivation includes the areas where the harvest occurs just once every 10 years, and reaches 57 °N, while the zone of industrial viticulture extends only up to 47 °N., The methods used for grapes cultivation in amateur conditions are not applicable on an industrial scale. We cannot extrapolate our findings to amateur viticulture.

Fresh grapes in this paper is equivalent to table grapes, as only table grapes were subjected to sensory analysis fresh, while the wine grapes were not tasted, but turned into wines and only wines analysed sensorially. The “fresh grapes” may be better replaced by “table grapes” in the title and the rest of the text.

А: Our research involved multipurpose varieties that are used both fresh and for making wine.

Lines 29-30 are implying that climate change is most important in viticulture and winemaking, a fact that was not demonstrated anywhere in the paper. Climate change is important in many sectors, and one cannot say that nowhere is it more important than in viticulture and winemaking, especially when the results show in the end that wine scores were not consistently affected by the climate change.

A: We have removed this sentence.

Lines 31-33 refer to changes in climate and effects in viticulture observed in other countries, but do not give any reference for this. More references could be introduced here from the international research, including:

 “Georgeta Mihaela Bucur, George Cojocaru, Arina Oana Antoce, 2019, The climate change influences and trends on the grapevine growing in Southern Romania: A long-term study, 42nd World Congress of Vine and Wine, BIO Web of Conferences 15, 01008 (2019), pp. 1-6, ISBN 9781510897663, https://doi.org/10.1051/bioconf/20191501008”

Some other papers, presented at OIV Congress in 2019 in Geneva (42nd WORLD CONGRESS OF VINE AND WINE, "Preservation and innovation: Expectations at the environmental, economic and social level", Book of Abstracts, ISBN: 978 285 038 0105, July 15th – 19rd 2019, Geneva, Switzerland) have only been published as abstracts:

Alyssa Ryan, Kelli M Archie, John Overton, Ralph Chapman, Climate change planning in viticulture: New Zealand winegrowers’ perspectives on adaptation

Rauf Asadullayev, Khadija Mammadova, Teymur Musayev, 2019, Influence of the local climatic specifics on storage ability of grape varieties in the conditions of Apsheron peninsula

Valentin Comte, Vivian Zufferey, Johannes Rösti, PierluigiCalanca, Martine Rebetez, 2019, adaptation strategies of a cold climate vineyard to climate change, the case of the Neuchâtel region in Switzerland

Etienne Neethling, Cécile Coulon-Leroy, Etienne Goulet, Philippe Chrétien, HervéQuénol, 2019, Effect of climate variations on grape composition and sensory profile: case of Chenin Blanc in the middle Loire Valley

А: we have increased the list of references.

Lines 36-38 contains a phrase with an unclear meaning. Please rephrase and explain what can be done scientifically to counteract the effects of climate change.

А: The text was modified as follows:

Lines 44-48: The development of the vine under climate change requires constant monitoring to adapt agronomic practices to global changes [13,14]. Measures for the adaptation of viticulture can be planned based on the assessment of trends in changes in economically important traits [9-11], their agrometeorological analysis and prediction [20-24]. These forecasts become the basis for optimizing the location of vineyards, irrigation standards, and other agricultural techniques [7,13,25,26].

Lines 54-55 - “but severe, long water deficits diminish must quality”. Authors should explain in what way the quality of must is affected, what parameters suffer detrimental changes.

А: The sentence was expanded to read:

Lines 64-67: but severe long-term water deficiency adversely affects the plant as a whole, negatively affects photosynthetic activity, causes leaf abscission and collapsing the ripening process, which reduces the quality of must and wine [11,25,42].

Lines 84, Table 1 and elsewhere in the paper: consider replacing the term “universal variety” with a clearer term, such as "variety with mixed uses” if this actually refers to the fact that these varieties have both wine and table grape traits.

А: We agree with the comment and suggest a replacement for the term “universal variety”, which, indeed, is misleading. We changed it for “multipurpose variety”.

In line 87 authors say “From the point of view of interspecies origin…”, but later in the phrase it becomes apparent that not all are "interspecies" since 139 varieties are V. vinifera L.”

А: We modified the phrase to read: Line 102: From the point of view of origin…

In lines 91-94, the ripening groups are defined in accordance to some number of days (for example, “ultra-early - up to 105 days”), but for the reader the meaning is not clear. It may probably be “days of vegetation”, or “a vegetation period of x days”.

А: We clarified the description:

Line 107: ultra-early (up to 105 days from bud break to full ripening of berries)

In line 114 the expression “Mean perennial values of all characters” is not at all clear and should be explained or redefined.

А: We modified the phrase to read:

Line 139: Average perennial values of all characters have been calculated for each variety

Author Response File: Author Response.pdf

Reviewer 3 Report

The article “The Influence of Climate Change on the Taste Scores 2 of Fresh Grapes and Wine in the Northern Zone of 3 Industrial Viticulture in Russia’ examines climate-related dependencies of fresh grapes and wine taste scores in the northern zone of industrial viticulture of Russia. The study concludes that the observed climate warming is favorable for viticulture in the studied region.

 

There are some comments and suggestions provided below:

 

Line 68: Add a picture with a collection location map. This information will be useful for readers not from Russia.

Line 63: The words “in recent decades” written twice in the sentence.

Line 84: The table 1 with the results of the calculation of points is located in the text before the description of the calculation methodology. It's in the Materials and methods section. Moved it to the Results section. At the first reading it is not clear where the points come from.

Line 109: Add some references with the Standards

Line 181: perhaps it is necessary to highlight in a separate subsection (3.3) the analysis of the relationship of climatic factors on the GS and WS

Line 238: Add some references after the text “however, in some studies…”

Line 254: The Conclusions section is incomplete. It should be expanded or merged with the Discussion section.

 

Supplementary Material

Number 97 in the Table S – Country or region of originэ is indicated in Russian

Author Response

Dear Reviewer! Thank you very much for your comments and suggestions, we agree with all your comments.

Line 68: Add a picture with a collection location map. This information will be useful for readers not from Russia.

A: A map was added, Fig. 1, Line 90.

Figure 1. Ya.I. Potapenko Don Ampelographic Collection location. Map is taken from [Afonin et al., 2008], modified. Red area – zone of industrial viticulture in Russia.

Line 63: The words “in recent decades” written twice in the sentence.

A: Thank you very much, redundant text omitted.

Line 84: The table 1 with the results of the calculation of points is located in the text before the description of the calculation methodology. It's in the Materials and methods section. Moved it to the Results section. At the first reading it is not clear where the points come from.

A: Thank you very much, we moved Table 1 to the Results, Line 173.

Line 109: Add some references with the Standards

A: We added:

Lines 110-113: The varietal dry table wines were produced by micro-winemaking in the laboratory of winemaking technology of the Ya.I. Potapenko All-Russian Research Institute for Viticulture and Winemaking, under micro-wine production conditions, according to a unified method in compliance with regulatory documents [46-48].

Some more information added:

Lines 114-120: Scoring of samples of fresh berries and wine was carried out at closed scientific tasting sessions by members of tasting commissions, approved by order of the Director of The Institute from among specialists of the Institute, in accordance with State Standard GOST 32051-2013 [49]. Control samples are always present at tasting sessions of both fresh grapes and wine. The varieties included in the Register of Breeding Achievements Permitted for Use (in the Russian Federation) are taken as control varieties. The name of the variety is disclosed after all members of the tasting committee have given their marks.

Lines 123-124: Fresh berries were evaluated by the method of organoleptic analysis accepted for State Variety Testing [43,50].

Lines 130-134: In addition to tasting scores, varieties were characterized by set of 12 agrobiological indicators (Table 2). The study of grape varieties in the collection was carried out using the methods and State Standards generally accepted in viticulture of the Russian Federation [43], sugar content and acidity were determined according to GOST 27198-87, GOST 32114-2013 [51,52]. The separation force and crushing force were determined according to the method by Prostoserdov N.N. [53].

Line 181: perhaps it is necessary to highlight in a separate subsection (3.3) the analysis of the relationship of climatic factors on the GS and WS.

A: We have added (Line 207) a subsection 3.2. Correlation Analysis of Taste Scores of “Average Variety” and add table with correlation coefficients with all the studied agrometeorological indicators to supplementary Table S2.

Line 238: Add some references after the text “however, in some studies…”

A: References added:

Lines 327-328: however, in some studies it is shown that the phenological events of the grapes are related to the temperature limits of 15 and 20°C [63-65]…

Line 254: The Conclusions section is incomplete. It should be expanded or merged with the Discussion section.

A: We have improved the Conclusion:

Lines 353-366: The analysis of grape varieties of the Ya.I. Potapenko Don Ampelographic Collection showed that taste scores of viticulture products depended on the interspecies origin of the variety, the lowest scores has the group of V. vinifera × V. labrusca hybrids.

In recent decades, the average taste scores of fresh grapes have increased in groups of varieties of various interspecies origin, and the wine scores have not changed.

An analysis of the relationship between taste scores of fresh berries and wines with agrometeorological conditions showed that the year-to-year variability of the former is determined by 50 or more percent by the weather conditions of the harvest year. In the conditions of the northern zone of industrial viticulture in Russia, the weather factor limiting the quality of table grapes is the lack of heat, namely, of temperatures above 15°C. The quality of the wine decreases in years with excessive midsummer rainfall, namely in the period with temperatures above 20°C.

The observed climate warming leads to an increase in the sugar content, in yield and in taste scores for the quality of fresh berries, i.e., is favorable for grapevine cultivation in the northern zone of industrial viticulture in Russia.

Supplementary Material

Number 97 in the Table S – Country or region of origin is indicated in Russian

A: Thank you very much! We corrected ‘АВСТРИЯ’ to ‘AUSTRIA’.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I am satisfied with the efforts made by the author's in response to the revisions I proposed.

However, I would caution that there may be several issue with English writing where the text was recently revised.

 

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