It’s crush time, big time

I was driving home last Thursday afternoon when my cell phone rang. It was Sean Donahue, my winemaking buddy. “Hi Jack,” he said, “What are you doing this weekend?” “I am kind of busy Saturday,” I replied, “and was thinking of going to the B. R. Cohn concert on Sunday.” Donahue said, “I am busy Saturday also, but the sugar is up to 26 (26 Brix) on the zin and we should start the crush. How does 8 a.m. on Sunday sound?”
This is the busiest time of year for the home winemaker. Because most home winemakers have “day jobs” the only time available is on days off, usually the weekends. Well, I thought, it looks like the Cohn concert is out for me.
The decision to harvest grapes is typically made by the level of sugar content measured in Brix. Brix is the measure of the soluble solids in the grape juice and represents the sugars and the acids and, to a lesser degree, the esters, terpenes, and tannins. The level of sugar is important because it will determine the final alcohol content of the wine, and because it is an indirect index of grape maturity.
The best time to pick is in the morning, when it’s cool. Sean Donahue has about 500 zinfandel vines so it wouldn’t be an all-day event. Picking grapes is not as easy as one thinks. It is easy to cut yourself if you use a grape-picking knife improperly; you have to position yourself so the knife goes away from your hand while holding the cluster. Additionally, you pick only the ripe clusters, and leave behind the clusters that are not ripe or contain “bunch rot” or other defects. It takes a little time to get used to it, but with practice you can become proficient at it.
After the grapes were picked, we transported them to our “crush pad” and into the destemmer. The stems have relatively high tannin content, and if not removed beforehand, give a vegetal aroma to the wine. Destemming also breaks the skins of the grapes, which aids the fermentation process.
We then poured the destemmed “juice” into the primary fermenter, a 60-gallon food-grade plastic barrel. Our reward was about 30 gallons of juice. Sulfur was added (approximately 40 parts per million) to rid the destemmed grapes of wild yeast and other “bad stuff.” On Monday, yeast was added and fermentation began.
Last year I was successful at making port and thought I would try again this year using the zinfandel juice. If I were not making port I would ferment the wine all the way down to 0 Brix with about 2 percent unfermented sugar remaining, then press it and put it into glass carboys or barrels for final fermentation and aging. Since I am making port, I will press the juice while the sugar is high, around 18 Brix. Brandy will be added to stop the fermentation process. The added brandy also raises the alcohol content to 20 percent, which is normal for port. Then I will place the port into a barrel for further settling, flavoring, and color.
This coming week the cabernet sauvignon grapes should be ready and the process begins again. Wonder what social events I will miss this weekend?
Jack Bertram is a Sonoma resident and brings a unique perspective to home winemaking. He is the President of the Valley of the Moon Dilettante Society (VOMDES.org).
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