If there is one thing I have learned the past 17 years while doing research in wine in is that wine can be quite complex. Due to the effects of variability in wine production, doing research and to a certain extend training in wine can be quite daunting.
However, this makes investigations into what makes a wine a wine challenging, but also very interesting. Variability is defined by the Oxford dictionary as “Lack of consistency or fixed pattern; liability to vary or change”. Let’s take Chenin Blanc wines for instance. Chenin Blanc is known as a very diverse cultivar, leading to a number of different wine styles. Fresh and fruity, rich and ripe unwooded, rich and ripe wooded etc. are all different descriptors linked to different Chenin Blanc wine styles. The same applies to a most other cultivars as well. Just look at all the different descriptors we found linked to a Chenin Blanc wine in the following image (the larger the fond of a word, the more this descriptor was mentioned by the persons tasting the wine).
Now where does all these variability comes from you might ask? I would order the origin of these into three categories. The first is the vine. Research has shown that the vineyard is the most important factor in terms of a wine’s composition, hence the old saying “Wine is made in the vineyard”. Where grapes are grown, the soil conditions, vineyard practices such as the canopy management, crop load, pruning etc. can all influence how the vine performs and the final composition of the grapes and ultimately, the wine. The type of rootstock and clone of a specific cultivar can also influence this to an extent.
However, the winemaking process, the second factor that can impact a wine’s composition, can also play a significant role in a wines composition and how it tastes. The most important decision a winemaker in my opinion must make that can influence a wine’s composition is when to harvest the grapes. Different ripening levels will not only lead to different alcohol levels in the wine, but to different flavour profiles and colour compositions in red wines for instance. Other aspects such as time spend on the skins before and during alcoholic fermentation (in the case of red wines), yeast choice, malolactic fermentation and the types and duration of wood contact can also play a large role in a wine’s composition and sensory appeal.
The third one is variability in our perceptions as humans. It has been proven that babies can already perceive aromas while in the womb. However, how these are perceived is very much influenced by our different experiences as we grow up. Luckily we are not lab rats (well most of us) that all grow up in a similar manner, so how we perceive things can be quite different between individuals. A large part of our generic make up is dedicated to our senses. This leads to large variably in how we perceive things, including wine. It has been shown that some persons are up to a 1000 times more sensitive for certain aromas and tastes than others. That is the reason why gauging quality in wine is so hard, as beauty (as well as quality in my view) in wine is definitely in the eye of the beholder.
If one then would like to understand the influence of a certain individual vinicultural or winemaking effect on a wine, one needs to assess only one variable. For instance, comparing a Chardonnay from Robertson that did not undergo malolactic fermentation (MLF) with one from Stellenbosch that did is not really valid if one would like to assess the effect of only MLF on a wine due to the above-mentioned reasons. One would need to make a Chardonnay from the same vineyard in the same way, except for say half of the batch completing MLF and the other half not and then compare these two wines to be able to do just that.
Luckily advances in modern analytics and data analyses abilities have made our understanding of what influences the composition of wine and how people perceive them easier. However, as we are still working with a natural product with so much variability, we will probably not be able to completely explain scientifically what makes a great wine tick very soon. Fortunately this also gives an air or romanticism to wine which is great, as science can sometimes be a bit cold and clinical. Just as well, as what is not without variability is my two boys’ increasing appetites, so I still need to be in this job for the next 17 years!