- Excessive Tannin Tannin is a bitter acid that is found in the seeds, stems and skins of the grapes. If the grapes are over crushed, or over pressed, or left in the fermentation too long, too much tannin can be extracted into the must.
- Over Oxidation This is essentially over exposure to air. If the finished wine sits in a partially-full wine carboy or plastic fermenter along with air, the wine can begin to take on the effects of oxidation. It can be noticed as a slight cough syrup flavor. You may also notice a subtle change in the wine's color. It the case of a Syrah, a shift to a orange hue.
Hello Adventures in Homebrewing: We have 17 gal of 2009 Syrah, it tastes a little bitter to us. Should we add conditioner before bottling? Thank you Bobbi ---------- Hello Bobbi, Wine Conditioner is not designed to cover up bitterness. It is a wine sweetener for people that do not like their wines dry. A better avenue would be to try to figure out why the wine is bitter. Then see if it can be remedied, not masked. There are two primary faults that can cause bitterness in a wine: