Wednesday, January 23, 2008

The Critical Phase

Yesterday I did two more punchdowns while the ferment was at its peak temperature: at 1:00 PM it was 15° Brix at 82° F and at 5:45 PM it was 13° Brix at 84° F. It took the WinePod heating unit eight hours to pull the must up from 72° F at 9:30 AM.

At this third punchdown I added another 10 grams each of DAP and liquid yeast extract. This brings the total for each to 46 g/hL. I also raised the lower temperature setpoint to 87° F.

At 5:30 this morning I went in to punch and check on the ferment: 7° Brix at 85° F. Whew - I was worried that the yeast might have tried to rocket through the rest of the sugar overnight. I left the upper temperature setpoint at 90° F and decreased the lower setpoint to 80° F.

At the 2:30 PM punchdown today the sugar was down to 5° Brix at 80° F, so I backed the lower setpointfurther to 78° F.

Ambient temperature in the winery is about 53° F. It's cold but not frigid. The WinePod is very efficient at shedding the heat of fermentation. All this fiddling with temperature setpoints is in an effort to get the ferment in the Pod to track with an idealized commercial fermentation temperature profile.

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