After the press, we moved into secondary fermentation of the wine in air-locked vessels. We used a 5-gallon glass carboy and three gallon jugs to use for top-up (I'll get into that later). This period was generally uneventful and less involved, but there were a few things that required attention.
Controlling the temperature. Malolactic (ML) bacteria, which was added to the juice the day before press, were quietly converting tart-tasting malic acids into fuller-bodied lactic acids. ML bacteria are sensitive to numerous factors (e.g. pH, SO2, and alcohol levels), but the one thing that worried me was my ability to keep the wine within the optimal temperature range (>70 degrees). The carboy and gallon jugs were wrapped in blankets, snugged in cardboard boxes, and gently warmed by a heating pad. My biggest fear was stuck fermentation since there were no easy tests to perform at home or measurements to track progress. I resorted mostly to prayers.
|Lees left behind from racking
We siphoned a total of four times; the first time was 24 hours after press, the next two were a week apart, and the final one was a month out.
Racking also has two other advantages:
- It clarifies the wine. You could literally see that the juice got clearer after each racking. In many cases, clear wine is just a matter of aesthetic. If the wine tastes good, cloudiness may not indicate flaws.
- When done correctly, racking can introduce controlled amount of oxygen into the wine. During the early part of secondary fermentation, oxygen has positive effects on unfinished wine by stabilizing the color and tannins. It allows the wine to mature gracefully and become more complex. In the later part of the secondary fermentation, caution is needed to minimize oxygen contact. If acetic bacteria is exposed to wine and oxygen, it will turn the juice into vinegar (acetic acid).
It is important to note that you will lose wine during racking due to spills and as you avoid siphoning lees. The loss of wine during racking may increase the air space between your wine and the airlocks. You can top up the carboy with wine from the jugs or similar store-bought wine (preferably same varietal and AVA). Alternatively, you can add sterilized marbles into your containers to raise the wine level. I personally put some of my top-up wine into a sanitized plastic container, squeezed out as much air as possible, and capped it. It worked!
- Residual sugar was at 0.3%. This was probably the least of my concern since we pressed the wine at a really low Brix. Residual sugar over 0.6% is a concern for still red wine as it may cause re-fermentation in the bottle.
- pH was 3.78. This was slightly higher (or less acidic) since harvest, which was at 3.53. But it was still within the normal range.
- Titratable acidity (TA) was 7.3125. TA measures the amount of total acids and was higher than our reading during harvest, which was 7.125. It was a bit higher than I like, but not bad.
- ML fermentation appeared to have completed. While not the most accurate way to test the concentration of malic acid, the chromatography test is cost-effective. The solvent used for the chromatography is extremely toxic, and the test takes several hours. After putting dots of wine sample onto a piece of chromatography paper, it was left in a big glass jar with the solvent and the lid closed tight.
|Chromatography test revealed that one of the wines still had malic acid
Once the wines had passed all the tests, they were ready to be bottled. We got the bottles that we have saved up, cleaned, and sanitized. (We recycled bottles. If you buy new bottles, you can skip the above steps.) Sulfites were added to the wine just before bottling. Sulfites are a preservative and will keep the wine fresh. They are also anti-oxidants and will protect the wine from oxidation.
|Adding sulfites to wine
|Siphoning wine into bottles
|Corking wine bottles
|Abscession 2016 Syrah
My Verdict: I am having so much fun learning about winemaking. It gave me a greater appreciation for wine. I don't think going commercial is my calling, but I'm planning for my next vintage already!