simple question, bet the answer isnt.....

Simple question but not a simple answer.

There are a LOT of variables a few of which but not limited to, pH, TA, Tannins, % Alcohol, type and style of wine and last but not least - storage conditions - AND peoples judgement and taste.

We need a biochemist I suspect, but I would like to know how each variable affects volatiles and 'constants'.

Jim

Not to forget the overall quality of the grapes that go into the wine.

Pp

I suspect a biochemist would not help much here. (I am a biophysicist so I feel qualified to comment on the lack of qualifications). There are lots of chemicals that come out of fruit and make up a wine. Some of these will break down over they years of aging. Some of these yield improvement and others will be detrimental. Wines that are made from juice will have fewer of these complex chemicals and generally are valued for their fruitiness. But the chemicals that yield fruitiness do not age well. Whites and some light reds fall into this group. They typically are best drunk young and decline after a certain period of time. One of the wines that I make that I really like will start declining after 6 to 9 months.

Wines made on significant amounts of skins like full bodied reds have a lot of chemicals that will break down and yield complexity that can be valued in wine.

Then there are some wines, especially some reds like Cab. Sauv. that have a very nice fruitiness when young, say 1 to 2 years or even less. As they age they will loose their fruitiness and go through a period when they are not that good. Then after they age for 3 to 5 years they tend to enter a period when they exhibit complexity and these are the wines that give all wines the reputation of improving with great age. Not all wines live up to this reputation.

Some of all this chemistry is understood, other parts of it is not. But then they really do not even know what chemicals are in each fruit. Just the major ones. If you want to learn some of this, a good introduction is Duncan and Acton's "Progressive Winemaking". That will probably go deeper into the subject than you want to go but will probably not answer your questions.

Ray