jason carr's mousepad storing pure yeast cultures in distilled water

The Big Idea

Some old mycological journals (back to the early 20th c.) describe methods that fungus and bacteria researches used to preserve live specimens without refrigeration. This suspension method may be useful to homebrewers.

This page is a very early first draft. Here is my original blog entry on this topic. Scans of the article that the blog refers to can be found as a torrent. There is also an HBD post on the topic. The Craftbrewer podcasts in Oct-Nov 2007 discuss the technique.

Potential benefits of the process

Very long periods of viability (years)
Stable at room temps; no need to refrigerate
No need to prepare agar or glycerol media
Possible to use very small tubes, as no media surface manipulation is needed

Storage of the yeast

pour 3-5ml of distilled into a culture tube or other autoclavable container.
cap loosely and sterilize in autoclave or pressure canner. Allow to cool.
use an inoculating loop to deposit a matchhead-sized glob of yeast culture in each tube. Include no agar/substrate/media: the yeast must be starved
cap, shake to distribute, seal w/parafilm or similar, store at room temp. Upon shaking the water will appear milky with suspended yeast, but the yeast will settle out after a couple of hours.

Recovery of the yeast

shake tube, unseal, and loosen cap
streak plate with a noc loop dipped in the water. Use the streaked culture to build a starter, or restreak into slants,freezes (gly* solutions), or other suspensions.
close and store. Re-use until recultured or contaminated, if desired.

$Id: dwyeast.orb,v 1.11 2009/10/21 22:14:44 mouse Exp $

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