Ask Wine Wizard

Will freezing affect the juice I get in a 5-gallon (19-L) kit?



Freezing kit juice
Will freezing affect the juice I get in a 5-gallon (19-L) kit? I am concerned about the variations that occur in home winemaking. My 6-gallon (23-L) primary fermenter works well but I only have one shot per kit. I want to take a standard kit (10-liter bag of Grand Cru Cabernet Sauvignon juice) and split it into five 2-liter batches. These batches would be stored, frozen in Ziplocks, awaiting their turn in my 1-gallon (3.8-L) primary fermenter. This would allow me to test the effects of acid adjustment, oaking, extra rackings and vacuum degassing using a common raw material starting point.
Jim Spencer
Greensboro, North Carolina

I think your idea of freezing small portions of kit juice is fantastic! I have always encouraged readers to experiment in meaningful ways that work for them and their particular circumstances; and it sounds like your arrangement will work for you.
The juice and concentrates that come with kits are already relatively microbially stable and are generally homogenous so they should freeze very well. I would just make sure that you measure your portions accurately and that you use your frozen material within three months or less. Also, Ziploc and other similar zippered plastic bags are poor vapor barriers, which is another good reason to use the frozen juice within three months of opening the kit container.
You might also want to be aware that when you thaw your frozen juice, you may observe some solid material that has “come out of solution” with the cold and has fallen to the bottom of your freezer containers as sediment. This is entirely normal and is exactly what happens when a wine is cold stabilized in the cellar. Cold can cause molecules in the wine that normally would be soluble at warmer temperatures to want to condense and become solids. If these tiny solidified molecules become big and heavy enough, they are no longer dissolvable in the wine and fall to the bottom of the container. They can look like small grains of sand or crystals and may be clear or slightly colored, if the wine has any pigment to it.
Actually, the fact that these solidified “wine crystals” can sometimes look like shards of glass is the reason that most commercial wineries cold stabilize all of their white (and some of their red) wines. Wineries are worried that un-educated consumers will believe that any crystals present are shards of glass and in a bid to avoid any panic, wineries pre-empt any possible sedimentation by subjecting wines to extreme cold (usually 30 to 40 °F/-1 to 4 °C) for a period of time (usually 24–72 hours) and then filtering the wine. “Wine crystals” and any other kind of sediment that could precipitate from juice with cold temperatures are completely harmless and won’t affect the quality of a fermentation to follow. For more information about stabilizing wines, see Daniel Pambianchi’s feature article in this issue, starting on page 46 and his “Techniques” column with tips for troubleshooting starting on page 71.
Finally, kit ingredients are highly buffered and tailored specifically to work a certain way, so tweaking the acidity can be tough. My colleague, and WineMaker’s “Wine Kits” columnist, Tim Vandergrift, recommends that acid adjustments be done post-fermentation on kits.