Fining is important part of the winemaking process where a fining agent is added to the wine to create an absorbent, enzymatic or ionic bond with the suspended particles, making them a larger molecule that can precipitate out of the wine easier and quicker. Fining agents is used to reduce astringency and remove tannins, microscopic particles and clarifying the grape juice or wines, they also take out some aroma and flavor. The fining agents can be organic and inorganic or mixtures of both. Some work electrochemically, with the agent having a positive charge attracting negatively charged particles and bind with them.
Lab tests should be performed in order to determine the proper amount of the fining agent to add to the wine.