This friend is trained in microbiology and wine production, so I figured he would have a definitive answer. He did not. He said that he wasn’t sure about the relationship between tannic acid and tannin, because the words have often been applied and misapplied.
Well, I said to myself, that clears everything for me!
Being fairly well acquainted with cool climate wines, I am positive that their aging potential is seriously helped along by their acid make up, especially tartaric, which is the dominant acid of a few that are natural to grapes—and if you find that your dominant acid isn’t tartaric when you make wine, it’s usually best to add some.
Over time, the overall acidity (and tannin) in wine mellows as various reactions take place during the aging process, but it’s pretty well known that the tartaric portion of the wine’s structure plays a great role in fending off spoilage organisms, and that allows for the slow aging transformations.
For a long time, it was believed that tannins worked similarly to acidity as wine aged. Today, however, that belief is questioned and in fact, some question whether tannin is at all important in the wine aging process.
One of the results of being vocal or opinionated is that others will find you and take you to task. I was recently taken to task by a California winemaker because I posted on the Wine Lovers forum that acidity is what allows white wines to age and tannin is what allows red wines to age—the latter having more tannin and less acidity than the former.
I was spouting a long-standing belief, but the winemaker will have none of that. He wants to know which scientific study has proved that tannins help wines to age.
I did some checking around and I can’t help my winemaker friend by providing a study to support the role of tannins on wine aging. I can, however, report that there are scientific studies on the effects of tannin in nutrition and many other areas of plant and human health. One of those effects seems to be that tannins slow down oxidation.
Here’s my question to the winemaker: if tannins indeed do slow down oxidation, wouldn’t that help wine age?
Here’s my other question to the winemaker: what IS the difference between tannin and tannic acids?
The below links are interesting reading on this subject. Notice within some of the links that tannins can link to tannic acids through a process known as esterifying, and that those acids are not nearly as strong as tartaric or another grape acid, malic, or even as strong as citric acid.
My sense of the situation is this:
Forget the nonsense that white wines don’t age as well as red wines. That old saw is proven wrong on a regular basis with just Riesling alone, but with many other whites, all with high acid content.
Reds surely do have lower acidity and higher tannin content than whites, yet many of them age rather well. I believe that the anti-oxidant effects of tannin has an awful lot to do with the aging of red wines. But that is not to say that all tannin acts that way.
Hidden in one of the definitions of tannin I found that certain tannins, particularly from woods like oak, oxidize more easily than grape tannins.
Hmm. Could that be why some reds age longer than others?
Although winemaking is a science, understanding wine is quite often a belief system. Read the links below for the science; then, like the rest of us, form your own belief system. But please, don’t tell others that your belief system is THE answer.
August 2008. All rights reserved.