Been making wine for quite a few years now. All I ever use for recipe guidance is a couple of pages photocopied from a book somewhen, consisting of a table of approximate values of key properties of thirty or so different fruits, a table of approximate alcohol content based on various amounts of sugar per gallon, and a ballpark figure for yeast's acid requirement. Works very well. I prefer working from principles rather than blind cookbookery, and my results are gratifyingly good on the whole.
However, the pages in question are lacking information on one key component of good wine - tannin. Ideally, I want some way of calculating how much to add, given the fruit input, to achieve a correct tannin content in the final wine. Something like "make tea using one/two/three teabags per kg of high/average/low tannin content fruit and add to must" ...
Can anyone offer any suggestions as to how to get somewhere close to this ideal?
Andy