Comparing Malbec Wines from Argentina and California: Can We Identify “Terroir”?

Many of us are familiar with the term “terroir”, though some are torn as to whether this is a real phenomenon, or if it was just something that the French made up to help sell their wines (I tend to fall in the former category).   I think most people agree that there is certainly something that gives wines from different regions a certain unique characteristic, though it has yet to be determine exactly what causes these particularities between regions, though in my opinion, it is likely a combination of many factors which result in a different “sum of parts” depending upon both biological, environmental, and viticultural/enological differences between winemaking regions.

One grape variety that hasn’t been the focus of many research studies examining regional differences in wine characteristics is Malbec.  Originally from the Bordeaux region of France, Malbec has most of its planting in Argentina, in the Mendoza region in particular, which in 2011 represented 86% of all the Malbec plantings in Argentina.  In the United States, the majority of Malbec is planted in California, which in 2011 accounted for 84% of the Malbec plantings in the country.  However, despite the fact that 84% of the Malbec plantings are in California, only 0.5% of all red grape plantings in California are Malbec.  In order words, while California has most of the Malbec in the United States, they have very little compared to more “traditional” red varieties such as Cabernet Sauvignon and Zinfandel.

Between the years 2000 and 2009, Argentinian Malbec imports have significantly increased from 50,000

cases to 1.4 million cases.  It is clear there is an increasing demand in the United States for Malbec, so why is it that production of Malbec in this country is so low?  How do California Malbecs compare to Argentinian Malbecs, and are there ways California Malbecs can be improved in order to tip the balance from imported Malbec consumption to domestic production and consumption?

The study presented to you today is, according to the authors, one of the first (if not the first) to compare sensory and chemical characteristics of Malbec wines from two different countries and different wine regions within those countries by controlling for winemaking technique and factoring in some environmental differences between the two countries.

Methods

41 Malbec wines from Argentina and California were analyzed in this study, with all 41 originating from different vineyards.   Grapes were harvested in the 2011 vintage, and within-vineyard variability was controlled as much as possible (i.e. they harvested grapes from the most uniform vineyards they could).  26 sites were located in the Mendoza province of Argentina from 4 wine regions (Luján de Cuyo, Maipú, Tupungato, and San Carlos), while 15 sites were located in California from 5 wine regions (Lodi, Monterey, Napa, Sonoma, and Yolo Counties).

In terms of climate data, only growing degree days and precipitation rates/levels for each region were obtained and analyzed.

Winemaking procedures were the exact same for Argentinian and California Malbec wines, in order to remove the winemaking technique variable from the equation.  Argentinian Malbecs were made following a particular “recipe” at the Catena Institute of Wine in Mendoza, Argentina, while California Malbecs were made using the exact same “recipe” at the University of California, Davis.

All wines were fermented in stainless steel tanks until dry, were macerated on their skins for 11 days, put through malolactic fermentation, then later racked, bottled, and closed with a tin screw cap.  None of the wines had any oak contact, nor did they experience any acid addition or filtration.

After bottling, the wines made in Argentina were carefully packed and shipped to California, with all wines analyzed within a year of bottling.  When waiting for analysis, wines were stored upright at 16.5 +/- 0.2^oC.

All wines were analyzed for the following: volatile aroma composition (60 tested), pH, titratable acidity, ethanol, and volatile acidity.

Sensory analyses were formed on all wines at the wine sensory laboratory at the University of California, Davis.  Sensory panelists were recruited from the University of California, Davis, for a total of 15 panelists tasting the wines from Mendoza, Argentina, and 14 panelists tasting the wines from California.  The first group of panelists had 5 females and 10 males, with an age range of between 21 and 69 years, while the second group of panelists had 5 females and 9 males, with an age range of between 21 and 70 years.  Some of the same panelists were in both groups.

Panelists tasted and analyzed the wines during 12 different sessions over a period of 3 weeks.  Wines were given in triplicate and were presented in random order with 6 or 7 wines tasted per session.  Tasting occurred in isolated booths under red light (to avoid variability due to colors), and wine was presented in black tasting glasses.  Water and unsalted crackers were available to the panelists to use as palate cleaners.

Results

Environmental/Vineyard Differences:

• Malbec vines in Mendoza were significantly older than the Malbec vines in California.
• Malbec vines in Mendoza were grown on their own roots, while the Malbec vines in California were
  

  Photo By Fred von Lohmann from san francisco (Wine Tasting: Malbec) [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

  planted on rootstocks.
• Malbec vines in California were planted further apart than they were in Mendoza.
• In regards to irrigation, California vines had drip irrigation, while Mendoza vines were flood irrigated.
• In regards to trellising, Malbec vines in Mendoza were in a Vertical Shoot Position arrangement with cane pruning, while California Malbec vines had some Vertical Shoot Position, Lyre, and Sprawl arrangements, with mostly spur pruning and a little cane pruning and box hedging.
• Average price of Malbec grapes were significantly higher in California than in Argentina ($1156/ton versus $820/ton).
• There were slightly fewer growing degree days in California than in Argentina.
• There was less precipitation during the growing season in California (104+/-59mm) than in Argentina (147+/-44mm).
• Vineyard sites in Mendoza, Argentina were at a significantly higher altitude than sites in California (1103+/-133m above sea level versus 190+/-200m above sea level, respectively).

Chemical Analysis

• 49 volatile compounds were detected in the Malbec wines, with all but one being significantly different between the wines made in California and Mendoza.
  • Isoamyl alcohol was not significantly different between California and Mendoza Malbec wines.
• Alcohol levels were significantly higher in Malbec wines from Mendoza compared with Malbec wines from California (15.6 versus 14.1, respectively).
• Sugar levels were significantly higher in Malbec grapes at harvest from Mendoza than in California (which is expected based upon the final alcohol content results).
• pH levels were significantly higher in California Malbec wines than Malbec wines from Mendoza (4.02 versus 3.76, respectively).
• Titratable acidity levels were lower in California Malbec wines compared with Mendoza Malbec wines (4.85 versus 6.06, respectively).

Sensory Analysis

For the sake of space, I am not going to describe the differences in sensory characteristics between sites within each country, though if you have specific questions about a specific area, please feel free to ask and I’ll see what I can dig up.

• The region of origin (i.e. Mendoza versus California) significantly differed for the following sensory characteristics: cooked vegetal aroma, earthy aroma, chocolate aroma, volatile acidity aroma, sweet taste, acidic taste, astringent mouthfeel, and viscous mouthfeel.
• Using Generalized Procrustes Analysis (GPA), chemical and sensory chacteristics of Malbec wines from each region, as well as the environmental data collected, were compared and contrasted, to look for any similarities or differences.
  • GPA showed some spatial analysis between country of origin, indicating that the Malbec wines from Mendoza have different chemical and sensory characteristics than Malbec wines from California.
  • Figure 1 below from King et al (2014) shows the results of the GPA analysis of Mendoza and California Malbec wines.
    • Circles represent chemical compounds found in the wine samples.
    • Squares represent the sensory characteristics noted for the wine samples.
    • Wine regions were placed on the graph depending upon which chemical and sensory characteristics that given wine region possessed.  NOTICE:  The majority of the Mendoza Malbec wines are more right and bottom, while the majority of the California Malbec wines are more left and top.  This indicates significant differences in the wines depending upon region.

• All wines were rated relatively high for astringency.
• California Malbec wines were rated higher for bitter taste than Mendoza Malbec wines.
• Common sensory descriptors for BOTH Mendoza and California Malbec wines included:
  • Cooked vegetal aroma, earthy aroma, soy aroma, volatile acidity aroma, acidic taste, and astringent mouthfeel.
• Malbec wines from Mendoza also possessed these unique sensory characteristics that California Malbec wines did not:
  • Red fruit aroma, dry fruit aroma, chocolate aroma, sweet taste, hot mouthfeel (this last one makes sense since the alcohol levels were higher).
• Malbec wines from California also possessed these unique sensory characteristics that Mendoza Malbec wines did not:
  • Artificial fruit aroma, grapefruit/citrus aroma, bitter taste.
• Overall, there were more sensory descriptors noted for Malbec wines from the Mendoza region of Argentina compared with California Malbecs, indicating that Argentinian Malbecs have increased complexity compared with California Malbecs.
• Altitude was positively correlated with titratable acidity, ethanol, and volatile acidity (meaning when altitude increased, TA, ethanol, and VA increased), and negatively correlated with pH (meaning when altitude increased, pH decreased).
• Altitude was positively correlated with precipitation.
• Precipitation was positively correlated with titratable acidity, and volatile acidity, and negatively correlated with pH.
• Growing degree days was positively correlated with red fruit aroma, bitter taste, and pH, and negatively correlated with earthy aroma, sour taste, and titratable acidity.
  • Malbec wines from hotter climates generally had more red fruit aromas and higher pH, while also having less earthy aromas, sour tastes, and titratable acidity.

Conclusions

The results of this study provide a nice comparison of Malbec wines between two different wine growing regions, California and Argentina.  Controlling for winemaking technique by having each site make the wines using the exact same procedures was a good idea, as now any differences found should be related to viticultural practices or terroir.

One thing I wish the researchers measured was the soil content and soil chemistry.  Soil can have a huge influence on the growth of the vines, as well as influencing the sensory characteristics of the wine made from those grapes, so it would have been interesting to compare the differences in soil chemistry between the two regions.  While growing degree days, precipitation levels, and altitude were certainly important and I’m glad

they were put into the model, I think having the soil data would make the comparison that much more interesting.

While there were some sensory characteristics that were the same between the two regions, indicating that they might be a function of the grape variety itself and nothing else, the Malbec wines made in the Mendoza region of Argentina had an increased level of complexity that they California wines did not have.  What causes this complexity?  Is it due to the environmental differences between the two sites?  How about soil differences?  And what about vineyard age and viticultural technique differences?  Clearly, these differences are contributing to the complexity of the Argentinian Malbecs, however, it is unclear from this study what has the greatest influence, or if the variability is spread out relatively evenly among the different variables.

Since increased imports of Argentinian Malbecs has been observed, perhaps this study could be used to help growers in California and elsewhere in the US develop a Malbec in the style that appears to be sought after by consumers, so that they can take a bigger bite of the market pie than they have at the moment.  I think there is a huge opportunity to increase sales of California (or other US) Malbecs, and this kind of study could help growers and winemakers learn all they can about the competition, so that they can also develop a complex wine that is highly desirable to consumers.

What do you all think of this study?  Do you have any questions/thoughts/comments to share?  Please feel free to join the discussion!  Cheers!

Source: King, E.S., Stoumen, M., Buscema, F., Hjelmeland, A.K., Ebeler, S.E., Heymann, H., and Boulton, R.B. 2014. Regional sensory and chemical characteristics of Malbec wines from Mendoza and California. Food Chemistry 143: 256-267.