Dead Yeast Cells Aren’t Much Fun

Going nowhere fast.

Going nowhere fast.

Two things you may not know about me are: 1) I can be a penny-inching miser (comes from standing in food lines as a child) and 2) I grew up listening to the Dr. Demento Show (yes, I was a nerd).

So, when my son’s small batch of Aglianico was not showing any signs of fermentation (after he pitched the yeast), an old favorite started to play in my head.

I had some open packets of RC212 and D47 in my bins of winemaking supplies, so we decided to take a pinch of each, reactivate them and run the ferment with that mixture.

When there was no activity, I first checked the must temperature. When that was in an appropriate range, I ran a little experiment:

I mixed up some water, sugar, DAP and StartUp powder. I divided this into three glasses. In one, I attempted to reactivate the RC212, in another the D47. In my “control” glass I reactivated some Fleischmann’s baker’s yeasts from a freshly-opened packet.

Sure enough, after a few hours, the Fleischmann’s was bubbling vigorously, while the other two mixtures were perfectly still after a few hours.

I had opened these packets of RC212 and D47 last October/November and then sealed them in zip-lock bags. It turns out that this method is insufficient for preserving yeasts. As a matter of fact, although these are freeze-dried yeasts, cool(-ish), dark, dry storage conditions are not enough to maintain their viability once the packet is opened.

Oxygen is the greatest enemy of freeze-dried yeasts. When I ordered some yeasts from Napa Fermentation earlier this week, it was recommended that I store the left overs of the 500-gram brick I will be getting either in vacuum-sealed bags, or in zip-lock bags into which I should first inject inert gas, and then squeeze out any gas. Refrigeration is an obvious plus.

Lesson learned.



Father, husband, physician, amateur guitarist, wine lover, wine writer, wine grower and wine maker trying to do it all within eye shot of downtown Los Angeles.
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