perform well, yeast must be allowed to respire, consume and reproduce.
If yeast is to do all that we
demand, certain care must be taken, especially during storage. This
5-step regime removes waste products, kills bacteria and ensures robust
yeast health. You will be rewarded with more consistent
fermentation, better-tasting beer and a greater number of generations from
yeast immediately after final gravity has been reached, before diacetyl
Even if it is kept very cold, yeast should not be stored
on the cone or under beer. To yeast, beer is a nutrient-poor waste
product, and forcing it to reside there may cause the viability to drop
precipitously (over 50% within 48 hours), no matter how cold it is kept!
Sterilize valves with 70% alcohol and flame, and
sanitize any hoses, utensils and storage containers to be used.
Catch the MIDDLE LAYER of yeast in a storage container as follows,
discarding top and bottom layers:
CONICAL vessels require draining the bottom trub-filled layer
until good color and consistency is seen.
ROUND vessels require manual harvesting with a paddle (layers
mix if allowed to drain through the valve).
Thoroughly degas yeast by shaking storage container and allowing gas to
escape through lid.
2) Clean the
often occurs during transferring and handling, so it is wise to treat the
yeast once it has been harvested and safely contained. Do not use
the standard acid-wash, for it often leaves live bacteria behind and
lowers yeast viability. Use the chlorine dioxide method given below,
which has proven to be both extremely effective on all types of brewing
bacteria and yet gentle enough on brewing yeast to use every harvest (see
Sep/Oct '98 issue of The New Brewer for details).
gallon of yeast, acidify about 100ml of water with a pinch or splash of
citric or lactic acid.
For every gallon of yeast, add 2ml* sodium chlorite to the acidified
When concoction turns a very pale yellow (may take a minute), add to the
yeast slurry, mixing well.
Allow to sit for a minimum of 30 minutes (longer reaction time ensures
effectiveness) before using.
*Available from BIRKO as DioxyChlor™
at (800) 525-0476 and Five Star as Star-Xene™
at (800) 782-7019.
3) Feed the yeast
(if to be pitched within 48 hours, skip the feeding and store at 34°F/1°C).
It has been
under pressure and awash in its own waste products -- alcohol and carbon
dioxide -- so it is not in tip-top condition. Add a volume of
sterile, aerated wort equal to the volume of the slurry.
No need to mix; the yeast will resuspend itself in the wort. Do not
seal yeast container.
4) Store at 34°F/1°C.
Washed and fed
yeast will retain high viability for 2 weeks at this temperature.
Warmer temperatures will decrease storage times. If your cold room
maintains temperatures higher than 34°F/1°C, you must either place the
yeast storage container in an ice bath in the cold room (which maintains
an ideal temperature as long as ice is present), or you must feed the
yeast more often. If storage times of more than 2 weeks are desired,
drain old wort off the yeast bed and replace with fresh wort every 2
5) Test your
slurry before pitching.
Don't brew blind-folded! Check viability, cell count
and purity. See our
Laboratory Handbook for easy-to-follow procedures. Use our free
Pitching Rate Calculator.
AND FEED YEAST CARE KIT- $30
Why hose that perfectly good yeast down the
drain just because the next brew day is too far out? This unique
product allows you to prepare yeast for weeks of storage in 30 minutes flat.
Using pre-measured quantities of sterile cleaning and feeding solutions,
this simple, two-step process allows you to "clean" the slurry
with activated chlorine dioxide to kill any bacteria present, and
to "feed" the yeast with sterile, concentrated wort. Then,
store the slurry at 34°F/1°C, until needed, for up to 2 weeks.
Treatment can be repeated innumerably. Treats the quantity of yeast
cropped from a 10-bbl batch.
To order visit our