Monthly Archives: April 2012

The Economic Effect of Climate Change on Viticulture

Posted on April 30, 2012 by Becca| 4 Comments

Regardless of what you believe is the cause, global warming and climate change is occurring.  Depending upon where one looks around the globe, climate change affects specific areas of the world differently.  Specifically, in regards to wine and viticulture in California, studies have shown that global warming could have negative effects on the quality of wine (Pinot Noir, specifically) in the region, which would likely be reflected by lower prices.

Is it possible that some areas of the world will see positive benefits of global warming?

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The paper reviewed today, though now a couple of years old at this point, aimed to examine the economic impact of global warming on viticulture in the Mosel Valley of Germany, which lies between 49.61o and 50.34o latitude.  Within the Mosel Valley, production of grapes depends upon specific site characteristics such and steep slopes on rocky/infertile soil and specific weather conditions to allow for winter survival and successful ripening.  As a result, wine quality (as well as prices) depend upon weather and can therefore vary widely from year to year.  Due to these specific limitations and characteristics in the Mosel Valley, it is expected that temperature-induced changes due to climate change will have a direct impact on the economics on this part of Germany.

In order to study the economic impact of global warming on viticulture in the Mosel Valley of Germany, the authors used the “Ricardian” approach that has been verified and validated by other studies focusing on the effects of climate change on agriculture.  To be more specific, the authors created their three models based on different price data, including retail, wholesale, and auction prices.

Model and Data

The data this model focused on revenue and its components.  Per hectare revenue between 1997 and 2008 in each of the 5 viticultural areas of the Mosel Valley were examined (Upper Mosel, Middle Mosel, Lower Mosel, Saar, and Ruwer Valley).  Revenue is basically calculated by the product of price and crop yield, though there are some other complexities that result in deviations from this simple formula, such as how wines in the Mosel Valley are labeled and marketed. 

Basically, German wines are classified and labeled according to the natural sugar content of the grape must (unfermented) based on the Oechsle cale (oOe):  the sweeter the must; the higher the alcohol; the stronger the aroma; and finally the higher the quality.  The quality of wines increase in the following order: Quality Wine (no oOe requirement), Kabinett (70oOe), Spätlese (76oOe), Auslese (83oOe), Beerenauslese (110oOe), Eiswein (110oOe), and Trockenbeerenauslese (150oOe).  Wine prices are thereby determined by the vineyard where the grapes were grown and by the quality level.

Data for revenue per hectare are not readily available; however, they can easily be calculated by multiplying crop yield data by the average prices for each region and each wine quality level.  Wine prices by region and by quality are not readily available; however, they can easily be calculated by drawing on various wine price data using three different sources (retail, wholesale, and auction).

Wine production data by region and by quality between 1997 and 2008 was provided by the Statistical Office of the State of Rheinland-Pfalz and its agricultural commission (Landwirtschaftskammer).

A disadvantage to using retail and wholesale price data is that they refer to posted prices, not transaction prices (though sometimes they are).  Conversely, an advantage to using these data is that they cover a wide range of wine producers in the Mosel Valley.  Auction prices, while they do represent actual transaction prices, only a very small percentage of Mosel Valley wines are represented and sold, so auction prices may not be representative of the Mosel Valley region in general.

Retail price data from 1994 to 2008 came from the Gault Millau Wine Guide for Germany.  This guide contained detailed information about wine age, geographic origin, and quality classification, as well as the data to allow for the calculation of wine prices and quality levels per region.  Wholesale price data from 1993 to 2001 came from the Mainz Wine Trade Fair (Mainzer Weinbörse).  Auction price data from 1981 to 2008 came from the wine associations VDP Grosser Ring and Bernkasteler Ring.

Auction wines, though in the past represented a great variety of wines in the Mosel Valley region, primarily serve now as a showcase for a few very high quality wines.  For example, only 0.13% of wines auctioned are Quality Wines (lowest quality), while 74.1% of all wines produced in the Mosel Valley are at the Quality Wine level.  Also, 12% of the wines sold at auction are Eiswein, Beerenauslese, or Trockenbeerenauslese quality levels, whereas these quality levels only represent 0.2% of the total production of the Mosel Valley. 

According to the authors, responses of prices to temperature during the growing season are very sensitive to these higher quality wines, making it likely that these data will suffer from selection bias.  Also, the auction price data are likely to overstate the average effect of temperature on price.  In years of good weather, yield reduction is practices in vineyards production higher quality wines, therefore prices of these quality wines are already partially a result of weather.  Crop yields more fully reflect weather variation in the Upper Mosel region, where quality of wine is lower and yield reduction is seldom practiced.

Results

  •       Wine quality and price are highly dependent upon weather, as seen in other studies.

o   In more northern latitudes, warmer and drier weather are expected to yield higher quality fruit.

o   Warmer weather had a significantly positive effect on prices.

o   Higher quality wines benefitted from a warmer growing season than lower quality wines.

o   The effect of temperature increase on price was greatest in the regions of Saar and Ruwer.

  •        Auction prices were significantly more sensitive to temperature changes than retail or wholesale prices.
  •       There was a greater production of higher quality wines in warmer years.

o   Increases in temperature resulted in an increase in wine prices within each quality level.

o   Increases in temperature resulted in higher number of higher quality wines than lower quality wines.

  •       Revenue per hectare significantly increased with increasing temperatures.

o   The extent of this effect depends on which price structure one is considering:

§  Auction price data suggested increases in revenue of 63% per degrees Celsius increase.

·         Since auction data focuses mostly on high quality wines, this result is most likely an overestimate of the revenue increase due to increasing temperatures.

§  Wholesale price data suggested increases in revenue of 27% per degrees Celsius increase.

§  Retail price data suggested increases in revenue of 37% per degrees Celsius increase.

Conclusions

All three models employed in this study suggest that the vineyards of the Mosel Valley in Germany will increase in value as a result of increasing temperatures caused by climate change.  Auction prices will likely overestimate this increase, whereas retail and wholesale prices more accurately represent the potential effect of global warming on changing prices of wine. 

According to the results of the models, the authors predict that a 3oC increase in temperature would more than double the value of the vineyards in the Mosel Valley region.  A more moderate increase of 1oC is predicted to result in an increase in revenue of about 30%.

One thing that’s not certain is whether we will continue to see this trend as the future progresses, or if we are in a more transitional period with much more change to come.  The only thing we can do is to continue running these models and adjust parameters accordingly depending upon any new changes observed.

The authors described a few more limitations of the models used in this study.  The first limitation is that the model does not take into account any general equilibrium effects that may occur with the restructuring of land prices.  Specifically, if there were to be any dramatic changes in prices of vineyard land itself due to climate change, there could be consequences for the final results of the price analysis.  Another limitation presented by the authors is that the results presented represent only a small fraction of the overall appraisal of the role of climate change on vineyard and general agricultural values.  Finally, it’s possible that too high an increase in temperature would be detrimental on price, if the grapes were subsequently damaged by excessive heat.

I’d love to hear your thoughts on this topic.  Please feel free to comment below (no html tags, please).

Source: Ashenfelter, O., and Storchmann, K. 2010. Measuring the Economic Effect of Global Warming on Viticulture Using Auction, Retail, and Wholesale Prices. Review of Industrial Organization 37: 51-64.

DOI: 10.1007/s11151-010-9256-6
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Economics

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Moderate Alcohol Consumption Lowers Risk of Oral Cancer in Postmenopausal Women

Posted on April 26, 2012 by Becca| Leave a comment

It has been well documented that alcohol consumption is a strong risk factor for oral cancer, as well as other upper alimentary tract cancers, especially if it is combined with smoking.  Alcoholic beverages are chronic irritants to the throat, specifically on the oral and pharyngeal mucosa, which leads to chronic inflammation and the release of problematic free radicals and cytokines.  These free radicals can cause chain reactions with other compounds within the body, resulting in an increased risk for malignant tumors.

The ethanol in the alcoholic beverage, though alone is not dangerous, can metabolize and produce acetaldehyde, a mutagen and carcinogen, which binds directly to DNA and transcription factor proteins, which ultimately lead to tumor development and growth.  Alcohol consumption also changes the metabolic and hormonal equilibrium in the body, sometimes with positive implications for human health.  Mild to moderate alcohol consumption has been shown to reduce the prevalence of metabolic syndrome, Type-2 Diabetes, and cardiovascular disease. 

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For post-menopausal women, moderate alcohol consumption has been shown to have cardiovascular health benefits, by decreasing coagulation activity, improving dyslipidemia and antioxidant capacity, in addition to improving estrogen levels in the body.  For men (middle-aged), no alcohol or heavy alcohol consumption are risks for insulin resistant states, while moderate alcohol consumption decreases this risk following a U-like relationship.  In the elderly, lifetime alcohol consumption is associated with increased risk of Type-2 Diabetes, cardiovascular disease, as well as other diseases in a U-shaped relationship.  Conversely, in the elderly, moderate alcohol consumption is associated with a lower risk of morbidity and mortality (no or excessive consumption leads to a higher risk).

In regards to oral cancer, the disease is more frequent among those with insulin resistant Type-2 Diabetes.  Some evidence has shown that moderate alcohol intake may reduce overall cancer risk in postmenopausal women by increasing insulin sensitivity, and maybe also increasing estrogen protection.

The aim of the study presented today, which was published last year, was to clarify the information in the literature regarding the dose-related risk of alcohol consumption for oral cancer by examining both male and female non-smoker patients.

Methods

A total of 608 non-smoking inpatients with histologically confirmed squamous cell oral carcinomas were included in this study (466 men and 142 women).  264 men and 142 women were used as tumor-free controls.

Data was collected via questionnaires and case reports.

For each female cancer patient, an aged-matched control was used (within 6 months of age difference).  For each male cancer patient, an aged-matched control was used (within 1 year age difference).

Participants were considered as “non-smokers” if they had never smoked at all, or if they haven’t smoked in 10 or more years.

Alcohol consumption habits were recorded, including how much and what type of alcohol was consumed.  Those drinking only on special occasions were considered non-drinkers.  Participants were considered moderate consumers if they drank less than 25g of alcohol per day (1 bottle of beer, 2dl of wine, or 0.5dl of spirits).  Participants consuming greater than 25g of alcohol per day were considered excessive drinkers.

Blood glucose levels were measured for all participants.  Those with glucose levels of 5.6mmol or higher were considered insulin resistant.  No Type-1 Diabetes patients participated in this study.  For postmenopausal women, ratios of postmenopausal cases and the mean onset of menopause were calculated for both cancer and control groups.

Results

  •       The mean age of female cancer patients upon admission was significantly higher than the mean age of male cancer patients.
  •        In the male cancer group, 41.8% were excessive drinkers, and 7.1% were moderate drinkers.
  •       In the male control group, 23.4% were regular drinkers, though out of those, the majority were excessive drinkers.

o   In men, excessive alcohol consumption was found to be a risk factor for oral cancer.

  •       In the female cancer group, the rate of regular alcohol consumption was significantly lower than the male cancer group (15.4% versus 48.9%).
  •       In the female cancer group, excessive consumption was predominant (12.6%) and moderate consumption was low (2.8%).
  •       In the female control group, excessive and moderate alcohol consumption rates were both low (2.1% and 4.2%).

o   In women, excessive alcohol consumption was found to be a risk factor for oral cancer.

o   In women, moderate alcohol consumption lowered the risk for oral cancer.

  •       Elevated blood glucose levels were similar between males with cancer and males in the control group.
  •       Elevated blood glucose levels were significantly higher for females with cancer compared with female controls (58.4% versus 42.2%).

o   Elevated blood glucose levels are a risk factor for oral cancer in women.

  •       Mean age at menopause was significantly lower for females with cancer compared to their cancer-free controls (45.4 years versus 51.3 years).

Conclusions

The results of this study showed that in women, consumption of alcohol is a very important risk factor for oral cancer.  At lower levels of alcohol consumption, the results showed that men retain a moderate risk of oral cancer, whereas women actually have a reduced risk of developing the disease.  At higher levels of alcohol consumption, both men and women showed increased risk for oral cancer.

Why is there this difference between the sexes?  The authors speculated that these differences may be explained by the menopausal and hormonal changes that occurred in the women of the cancer group.  They claim that moderate alcohol consumption may reduce this risk of cancer in postmenopausal women by increased insulin sensitivity, or through increased estrogen levels.  Since studies have shown that insulin resistance in a high cancer risk factor for women, particularly after menopause, then increased insulin sensitivity caused by moderate alcohol consumption may be a justified therapy for reducing the cancer risk.

One thing I would have liked to have seen from this study is a breakdown of the different types of alcohol consumed.  Will any type of alcohol consumed moderately reduce the risk of oral cancer in postmenopausal women?  Or do wine, beer, and/or spirits act differently in the body?  The authors indicated that this data was collected; however, they never appeared to do any analysis with it. For example, we’ve seen from previous studies presented on this blog that different types of alcoholic beverages act differently in the body in regards to Alzheimer’s risk: specifically, those drinking mixed alcoholic beverages showed more negative effects on mental status than those consuming wine alone or beer alone.  What about oral cancer and types of alcohol consumed?

I’d also be curious how these results change when compared with patients who are smokers. Does smoking change this supposed reduced risk of oral cancer found in postmenopausal women? Or does smoking “override” these benefits and there is increased risk no matter how much or how little alcohol is consumed?

I’d love to hear what you all think about this study, the results/methods/conclusions/what have you.  Please leave your comments below (no html tags, please).

Source: Takács, D., Koppány, F., Mihályi, S., and Suba, Z. 2011. Decreased oral cancer risk by moderate alcohol consumption in non-smoker postmenopausal women. Oral Oncology 47: 537-540.

DOI: 10.1016/j.oraloncology.2011.04.003
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Health

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Influence of Geographical Location on Volatile Composition of Spanish Oak

Posted on April 24, 2012 by Becca| 7 Comments

The use of oak in wine making, be it with oak barrels or oak chips, has a significant effect on the flavor, aroma, texture, and color of the finished wine.  Traditionally, three different species of oak have been used for wine barrel fermentation and/or aging: Quercus alba L. (American oak), Quercus petraea (Matt.) Liebl., and Quercus robur L (both French oak). As a result of overcropping of the oak trees, or the harvesting off more oak trees than can be regrown for future use, in addition to the quest for more variety, new sources of oak for wine making are being explored.  Oak from Eastern European countries such as Ukraine, Russia, Romania and Hungry are starting to be used more in wine making, including similar species as used in France (Q. petraea and Q. robur) and another species used less frequently: Q. pyrenaica, which frequently hails from Spain.

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The use of oak barrels in wine making significantly influences the volatile composition of the finished wine, which in turn affects the flavor, aroma, and taste of the wine.  Studies have shown that there are quantitative differences in the volatile composition of wine made from American versus French oak barrels.  Furthermore, studies have shown that the Spanish oak, Q. pyrenaica, also shows significant differences in volatile composition of the wood, including higher levels of eugenol, guaiacol, and other volatile phenols and furanic aldehydes.  Looking at phenolic aldehydes and ketones, Spanish oak appears to retain levels between that of French and American oak. 

The amounts of these volatile compounds that are extractable from the oak wood are extremely important in determining the overall aromatic profile of the finished wine.  As a result of this, understanding the chemical composition of Spanish oak (Q. pyrenaica) is extremely important.  Studies from other oak species have shown that there is strong variability in the volatile composition of oak wood within the same species, tree, forest, stand, etc, due to various environmental and geographical factors. 

The study presented today aimed to add to the literature of oak wood volatile composition by examining Spanish oak, Q. pyrenaica, and to evaluate the effect geographical location, site, and silvicultural parameters had on them.

Methods

The sample set included 107 samples of Q. pyrenaica that were collected from several stands in three geographical locations in the northwestern Iberian peninsula (from the provinces of Ourense, Lugo, and Pontevedra).

From each tree, disks of wood were collected at a height of 1.3m above the ground.

From each of these disks, test tubes of heartwood were taken (20mm x 20mm x 40mm).

Heartwood samples were dried, then ground with a mechanical mill and sieved (

Volatile compounds were isolated and then analyzed using gas chromatography and mass spectrometry. 

Results

  •       The qualitative profile of volatile compounds obtained from Spanish oak was very similar to what has been reported for other oak species.
  •       There was high variability on several levels, including the levels of individual trees, forests, and geographical locations.
  •       Q. pyrenaica samples were high in cis- and trans-β-methyl-γ-octalactone (cis- was the dominant form).
  •        Samples were high in phenolic aldehydes, including vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde.
  •       Eugenol and isoeugenol were the major phenolic compounds found in all Spanish oak samples.
  •       Phenolic compounds also found in all Spanish oak samples were α-terpinol, γ-cadinene, δ-cadinene, 3-oxo-α-ionol, and vomifoliol (fruity and floral aromas).
  •       The most common semi-volatile present in the samples was β-sitosterol (antioxidant properties).

Silvicultural Parameters

  •       The most influential silvicultural parameter on volatile composition of oak samples was altitude.

o   The volatiles that were most affected were α-terpineol, eugenol, and vitamin E.

o   All correlations were negative:  the higher the altitude, the lower the concentration of volatile compounds.

  •       Organic matter and average annual temperature had some influence on volatile composition, specifically α-terpineol, vanillin, oxo-α-ionol, vitamin E, and α-amyrin.
  •       Distance from tree center, average annual precipitation, and number of trees per hectare did not influence the volatile composition of wood.

Soil Composition

  •       Volatile composition of oak in different soil types was similar.

o   Significant differences were found for the volatile aldehydes syringaldehyde, sinapaldehyde, and coniferaldehyde; and for tritperpenic compounds such as β-amyrin and derivatives and β-sitosterol (all with antioxidant properties).

o   For those compounds with important sensory influence, significant differences were found with α-terpineol, and 3-oxo-α-ionol (floral notes), and trans-β-methyl-γ-octalactone (coconut/woody notes).

  •       The greatest difference for all the above compounds were found in loamy soils.

o   Samples grown in loamy soils had the lowest levels of all of the above volatile compounds.

Geographical Location

  •       Samples from Lugo and Pontevedra were very similar.
  •       Samples fromOurense had lower levels of many volatile compounds compared to the other two locations.

o   Significant differences were found for guaiacol and vinyl guaiacol (smoky odor), syringol, eugenol (clove aroma), α-terpineol (floral odor), and coniferaldehyde.

  •       According to linear discriminate analysis, different geographical locations could determine/distinguish different chemical composition of wood samples of the same species.

Conclusions

The results of this study showed that some silvicultural parameters, such as altitude, organic matter and average annual temperature influence the volatile composition of Spanish oak, Q. pyrenaica.  Conversely, other silvicultural parameters, such as distance from tree center, average annual precipitation, and number of trees per hectare do not influence volatile composition.

Even though it was shown that Q. pyrenaica grown in loamy soils show some significant differences in regards to volatile composition compared to other soil types, linear discriminate analysis showed that soil type is a poor determinant in volatile composition of wood in Spanish oak. On the other hand, as with French and American oak, geographical location does have a significant influence on oak volatile composition, and is a good factor for volatile composition classification.

The results of this study should arm wine makers with information they need in order to make a decision on whether or not Spanish oak is right for the style of wine they wish to create, and which forest/province they should harvest the trees from.  Ultimately, however, I think the next step in this line of research would be to create a wine using barrels from Spanish oak from different geographical locations, and compare the oak volatile composition results with the finished wine volatile content as well as a sensory analysis.

What do you all think of this topic?  How many of you use Spanish oak barrels or Spanish oak chips in your wine making practice?  Please feel free to leave your comments below (no html tags, please).

Source: Alañón, M.E., Pérez-Coello, M.S., Díaz-Maroto, I.J., Martín-Alvarez, P.J., Vila-Lameiro, P., and Díaz-Maroto, M.C. 2011. Influence of geographical location, site and silvicultural parameters, on volatile composition of Quercus pyrenaica Willd. wood used in wine aging. Forest Ecology and Management 262: 124-130.

DOI: 10.1016/j.foreco.2011.03.011
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Chemistry

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Who’s Your Daddy?: Petite Sirah

Posted on April 20, 2012 by Becca| Leave a comment

For today’s “Who’s Your Daddy” post, we will be exploring the origins of Petite Sirah.

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Petite Sirah, also known as Durif or Petite Syrah, was originally developed in the late 1800s in France, though is probably most known for its wines produced from California grapes.  Petite Syrah tends to be a relatively robust grape, with sturdy long-lived vines that thrive in many different types of soil.  The grape clusters are relatively tight, so when located in humid environments, there is always the threat of rot.  The berries are also relatively prone to sunburn, so farming methods aimed to reduce this (perhaps more leaf cover) should be considered in particularly hot and sunny environments.

Durif/Petite Sirah was actually developed in France in order to resist Powdery Mildew, to which one of its parents is susceptible.  Even though the grape was ultimately resistant to this type of mildew, it was found to not be resistant to gray rot, due to its tight grape cluster as described earlier.  In the Rhone region of France, where this grape was initially developed, the weather is relatively humid, thereby gray rot risk is relatively high.  However, in the drier climate of California, gray rot doesn’t appear to be nearly as much of an issue, thereby Petite Sirah/Durif thrives there.  The grape seems to be doing so much better outside of its native region of France, that it’s now extremely rare in these original areas.

In regards to wine, Petite Sirah grapes are often used in blending, due to their deep color and intense tannins.  More specifically, this grape is often used to blend with Zinfandel, to add complexity, structure, and to ameliorate some of the characteristic “jamminess” of Zinfandel.  The small berries of the grape give a high skin-to-juice ratio, which produce wines with high tannin levels, high acidity, and a great ability to cellar.  Similar to its parent grape, Petite Sirah often displays strong hints of blackberry fruit and black pepper spice.

So, “Who’s Your Daddy”, Petite Sirah??

As we’ve already discussed, Petite Sirah was specifically created to be resistant to Powdery Mildew, unlike its parent.  Who are these parents we’ve been referencing?

Petite Sirah (a.k.a. Durif, Petit Syrah, etc) is the intentional cross of…..

Syrah……

 

…..and……

 

  …..Peloursin!!

Created in France, Durif was brought over to the United States by Charles McIver (then owner of Linda Vista Winery) in 1884.  It is thought that he was the first to refer to Durif as “Petite Sirah”.  Popular during Prohibition due to its tough skin hardiness and its ability to travel all across the country for home winemakers, its plantings reached up to 2/3 of all vineyard plantings in Napa Valley by 1933 after Prohibition was ended (together with the grape Alicante Bouschet).

Up through the 1960s, many plantings of Durif/Petite Sirah we done intermixed with other varieties, such as Alicante bouschet, Grenache, mourvédre, peloursin, and others.  Since several of these varieties are so similar to one another, and since they were often planted in such close quarters to one another, there is some debate over Petite Sirah wines created from these vines are actually Petite Sirah, or some sort of a blend of many varieties.

Want to learn more about Petite Sirah?  A great website for you to explore that educates all about this grape variety is P.S. I Love You, which can be found by clicking on this link.

I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Genetics

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