Three days into fermentation, and my poor grapes had gotten nowhere. These grapes had no help from yeast or yeast nutrients, and the situation was getting critical. The longer it takes for fermentation to begin, the more risk there is that harmful bacteria will gain a foothold and ruin the batch. I had done all I could to stimulate fermentation by stirring the grapes and the juice several times a day. Beyond that, the only thing to do was wait. Assistant winemaker Blair was smug, as his suggestion of various additions had been on the table since day one. But I had decided to keep my wine as natural as possible, and now here we were.
For optimal natural fermentation, the grape juice must have the right temperature. This is why modern fermenting tanks are temperature controlled. They must be warm enough to start the fermentation but cool enough for it to take time in order to let the flavors develop. Compare this to a bread dough which rises quickly near a warm stove but takes a whole night to rise in the fridge, or not at all if it’s cold enough. A really slow fermenting process is riskier but gives a more nuanced flavor and structure in the wine, and a lower temperature gives a more refined, fresh fruitiness.
All I had was a vat - a plastic harvest bin without any temperature control. What could we do?
Each morning, I moved the grapes out into the sunlight to be warmed, and each evening I moved them back inside to avoid the freezing nights. But even in the sunlight, only the top layer was getting warm. We needed to raise the temperature to get the fermentation started right away. In the end, it was Zach who figured out a solution. We’d build a little greenhouse.
We covered my bin in layers of plastic wrap until it was completely airtight, and then we rolled it back out into the California sunshine. I was constantly sneaking glances at it as Taka, the manager, kept me busy checking “Brix & Temp” on the large steel tanks to ensure that their fermentation was going according to protocol. Evenly declining sugar levels and even, medium temperature are signs of a successful fermentation, so measuring Brix & Temp twice a day was a common chore for every intern who passed through. And for one Swedish journalist.
During my first attempt, I dropped the thermometer into a large vat of zinfandel. None of my tools were successful in retrieving it, so I finally had to dive in myself. Literally. Taka pointed out that people pay good money at luxury spas to bathe in wine, but at least he couldn’t complain about the entertainment.
Every other hour, I lifted the plastic wrap around my grapes and stirred them with my hands. Sure, there were tools for this, but by using my hands I could really feel the temperature. We’d managed to achieve quite a lot of heat in the greenhouse, but the grapes under the top layers were cool when I went to check the first time. And the second time. And the third.
I began to despair. Maybe our little trick hadn’t worked. Or? Around sunset, when it really should have been time to hang up my head and collapse into bed, I saw a few bubbles along the surface. I dove back in under the top layer of warm grapes to feel around in the brew below. And there! One spot was warmer than the grapes around it. I squealed. There was a core of spontaneous fermentation!
Back on the game!
By the next morning, fermentation was racing ahead, and there was no doubt about it. The carbon dioxide it created had pushed the grape peels to the surface, where they lay like a thick blanket. The smell was fresh, warm, and fruity. Gratified, I smiled like a maniac and sang happy melodies to the must, while I broke up the peel with my hands. My hands, by the way, which were blue by now, and there was no getting it out no matter what chemicals or grandmother’s tricks I used. But what did I care about blue fingers when my whole soul was singing?
Perhaps this is why it feels so right to make wines without manipulation? The mass of grapes becomes a living being that I cannot control but which I can coax in the right direction. It’s just me and my bin and a very romantic experience of the process. Still, that’s easy for me to say when I don’t employ 100 people or make decisions regarding grape must worth hundreds of thousands of dollars. So my respect for Zach, Blair, Taka, and the others grew by the day. They work hard and love their job, but they have an additional weight to balance on the way to making that delicious bottle.
Continue reading the "Winemaker For A Harvest" Series:
>> Part 4: Coming Soon!
>> Part 5: Coming Soon!