Sunday, January 20, 2008

Inoculation - Cap Up

Today I went in to do my first "real" punchdown on the must in the WinePod, as the cap was up on the yeast I pitched in yesterday.

Yesterday made a small prophylactic addition of tartaric acid to the must of 20 grams (50g/hL). Then I prepped the yeast that was included with the WinePod starter kit. Here begins the gospel according to John, chapter 3 verse 1:

I used 200 mL of purified water at 104° F (it's critically important that the water has no chlorine). Then I suspended 20 grams of GoFerm nutrient in the water. GoFerm is another one of these magical yeast extracts – in this case, one selected for production of a high concentration of the sugar trehalose. This extract helps the active dry yeast to rehydrate with very little loss of viability.

Note that the commercial recommended addition rates are 30 g/hL for GoFerm and 25 g/hL for yeast. It is my confirmed opinion that it is better to over-inoculate than to use too little. My actual rates of addition were 47 g/hL and 37 g/hL, respectively.

Once the GoFerm was thoroughly dispersed, I added 16 grams of the Uvaferm 43 yeast included with the kit. According to Vinquiry's promotional material, Uvaferm 43 is a "[s]train selected for ability to restart stuck fermentations. Isolated in the Rhone valley, has shown consistent properties for adapting to sluggish or stuck fermentation. Alcohol tolerance greater than 18% (v/v), moderate/low nitrogen demand with good fermentation rate after lag time for adaptation to wine conditions. Contributes berry and cherry aromatics and slightly higher glycerol contribution." In my experience this yeast hardly ever "sticks". It also respects wine color and does not put its own stamp on the character of the fruit. Overall I think this is a great yeast to use for avoiding fermentation problems.

After 15 minutes I "proofed" the yeast preparation with a pinch of table sugar and 50 mL of juice from the fermenter. Proofing does two things: first, it confirms to me that the yeast prepartaion is viable (capable of fermentation and growth) and second, helps drop the temperature of the inoculum closer to that of the must, which is good for maximizing yeast viability.

Before pitching the yeast into the must I changed the setpoints on the WinePod temperature control to 70° and 80° F. I waited until the must was close to 70° F before I pitched the inoculum, which was at about 84° F when it went into the Pod.

After the punchdown today I increased the lower setpoint on the temperature control to 72° F to put a little more heat into the must. The sugar has dropped from 26° to 24° Brix.

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