I wrote this in August of 2007. Much has changed since then.
After we know that Malolactic Fermentation (MLF) is complete, the first dose of K meta will be made at this time ¼ teaspoon level baker’s teaspoon, per 5 gallon carboy. Having done this racking, the wine will be topped off to one inch below the bung. No other air space is allowed. You will then move the wine into the cold for the winter. This is called cold stabilization. How cold. Very Cold!!!! We would love the wine to stay at 25 degrees for the winter but we know that this will not happen. However, the wine will not freeze before 24 degrees to be safe. But reposts have it not freezing until 13 degrees. In any case, what you will do is leave a gallon water jug ¾ full next to the wine. If that water freezes then we will monitor the temp of the wine each day during the cold spell. You would be surprised how cold it will need to get to even freeze the water. The carboys will be placed on wood or card board or left in their crates. Not on the cement. We don’t want moisture from the floor to freeze the bottom of the carboy and if you were to move it the bottom might crack off. After the winter, usually in March, the wine will be racked again using the stick and the hose. It will be given another dose of K meta, ¼ teaspoon per five gallons. At this point the wine really needs to be bulk aged or go in a barrel, or bottled and drunk with Easter Dinner. But remember, you are drinking a teenager. I know some of you like teenagers….., but I digress. In any case, the teenager, in what ever form it is, in a bottle, in a barrel, or in the carboy needs to be kept at 55-65 degrees for its entire life. We should monitor the wine as it progresses and make adjustments to acid, tannin, and other adjuncts as could become necessary. The airlock must have either a solution of K meta or vodka. Those with a few carboys are advised to just use vodka. It won’t freeze and it is sterile, and will not lose its effectiveness, however it might evaporate sooner. For topping off the carboys after Racking a good quality commercial wine can be used. Those with more will have extra for topping.
What has changed ? The grapes have. Back then we were accustomed to adding lots of tartaric acid to raise the Tartaric Acid (TA) and lower the PH. Central Valley Grapes and Lodi are hot weather grapes with low acid and high PH numbers. Not great for taste and not good for long term aging without worry of microbiological spoilage. Now, since we are using Northern and Coastal grapes we are finding much better PH numbers and reasonable TA acid numbers. The result is we are not adding tartaric acid to many batches. Take for example a central valley grape with a ph of 3.9 and a TA of .40 (typical) you would need to use 11 teaspoons of Tartaric Acid in one carboy to raise it to .70, and that is what we did as a matter of practice. We got the PH down to a reasonable, safer level and we had a reasonable TA for a red. Except for one thing, the Acid is not stable. It will drop out in the form of bi tartrate crystals in your bottle if the wine gets cold. So, we lowered the temperature of the wine to drop out the crystals before the spring racking. Then they were eliminated forever to the temperature we subjected the wine to during the winter. The result was a TA that got lowered usually back down to .60 and the PH remained lower too. But what if we have perfect numbers? What if we don’t need to add acid? Do we want to lose the acid we have by exposing the wine to very low temperatures? The crystals are much less a problem because we did not add any. SO why do it? Well to answer that first you will get some crystals out at 35-40 degrees. So if you wine is not stored at lower temperatures again you will never get crystals in the bottom of your bottles. I like whites chilled so I think a white can use a cold exposure to 30 degrees. Also, whites have more acid to begin with and exposing it to cold will mellow out that acid. But do we want to lose it?
Pinot Grigio can have a TA of .90. This year we added a touch of acid to the Petite Syrah, we are letting taste guide us but the PH numbers were not that great, but certainly not a problem. Are there other advantages to Cold Stabilization? The cold helps with clearing and makes for compact lees so racking is easier. Now think about this, most boutique wineries in Napa don’t have a cold winter. Maybe only as low as 40. No more cold stabilization than that is used. And yes, your 150.00 dollar Napa Cabernet Sauvignon that you open may have a few crystals at the bottom of the bottle.
Guess what? No one cares, not even the Judges.
What am I doing with mine? Mine is in the garage. On Saturday it was 19 degrees outside and 36 in the garage. Cold enough for me. I am sure you are familiar with the expression, “The Art of Making Wine”. The major subtext that often gets over looked is, “The Art of the Acid”.
Read Jackish, “Modern Winemaking”, it is one book you must read. Buy a used one.