Tannin

Tannin is the ingredient that gives the wine a bite, or feeling of dryness on the tongue. It is a useful aid to clarification, and without it a wine would taste flat and uninteresting. Tannin is present in apples in sufficient quantities, and in most of the red fruits (elderberry in particular). If it is necessary to add tannin to the must, use 1/30oz/lg for white wine or double for red.