Tuesday, February 12, 2008

Second Trial: 2007 Napa River Ranch Cab

As I mentioned in Friday's post, I received three frozen pails of the 2007 Napa River Ranch fruit that morning. Yesterday, Provina founder Greg Snell came to Sonoma to install an upgraded logic board in the WinePod and bring me new software. We also made a fresh calibration on the Brix sensor.

It is my intention with this ferment to follow fairly closely the protocol I used to make the Rancho Sarco wine, in order to compare the potential of the two vineyards. It is also my goal with this trial to make no extemporaneous changes to the protocol that is available to potential WinePod users – I will be using only consumables from the kit, and testing the Wine Coach software. However, I will not be following the exact protocol suggested by the software – instead I will be validating the model and recommending changes and options.

Today I opened the pails of the Napa River Ranch fruit. Again, as with the Rancho Sarco fruit, there was no sensory evidence of yeast or bacterial fermentation, and no aroma of ethyl acetate or other oxidation flaw. The fruit looked sound, and there was no evidence of mold. Comparatively, the berry size of the NRR fruit was noticibly larger than that of the Rancho Sarco.

This time I added just 5 grams of Efferbaktol rather than the 10 grams I added to the last ferment. I dissolved the contents of the packet in 150 mL of warm water and poured 50 mL on top of the fruit in each pail. Then I transferred the contents of all three pails to the Pod. I used a liter of drinking water to rinse the three pails and transferred this rinse (with skins) to the Pod. Five grams of Efferbaktol provides the equivalent of 2 grams SO2, which calculates to a 46 ppm addition.

The Pod's temperature reading on the fruit was 54° F, the same as the ambient in the winery.

I suspended the 10 grams of VR Supra tannin (provided in the consumables kit) in 150 mL of warm water and added this to the fruit in the Pod. I followed this with the first punchdown to mix the must. VR Supra is a quebracho extract similar to the Vitanil AJ-11 from my commercial stash used on the last ferment. The 10 gram addition represents a rate of 25 g/hL (the recommended rate is 10-40 g/hL) compared to the total tannin addition of 15 g/hL in the Rancho Sarco ferment.

Note that this larger tannin addition may result in a slightly softer wine this time than what I achieved in the last ferment. This seems counterintuitive, but the extra tannin can combine with harsh and bitter seed tannins and render them softer.

The Pod was reading 25° Brix after the punch. I enabled automatic temperature control with the setpoints at 60° and 63° F.

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