Natural Cold Clarifying

One of the key things you can do in the very cold winter months is encourage your wine to clear properly. Wine is often fermented in the summer months and left to clear over the winter. Wine fermented over the summer will contain a lot of dissolved chemicals. Many of these chemicals, such as tartaric acid and certain proteins, are not completely stable in the wine solution. When wine ferments solely at room temperature, these unstable compounds will remain in the wine, many of them unnoticeable until the wine is introduced to varying temperatures. Because of this, many of these residual proteins will go undetected until it’s too late. However, if the wine is introduced to freezing temperatures, the unwanted proteins and/or acids will precipitate out and form crystals on the bottom of the wine.
When the temperature falls below freezing for a few days, carry your fermenters outside and leave them in a shed or in an uninsulated garage for 24 -48 hours. The amount of rubbish that comes out of the wine after a day or two is quite surprising. Water in airlocks is apt to freeze, so be sure to monitor that. If you live in a very cold climate there is a risk the wine itself will freeze- make sure the wine is kept between 15° F & 32° F.
Giving your wine the cold treatment not only clears the wine of the residue that will cause it to appear murky or cloudy, but by eliminating excess tartaric acid you’ll also tone down the tartness or bitterness of your wine.