From the HBD Archive
From: jdg@grex.ann-arbor.mi.us (Josh Grosse)
Subject: Dry Yeast Update
Date: 1992-06-26 01:47:20 GMT

I've some news of interest to active dry yeast users and
detractors, alike. First of all, some business news:

o I can confirm the rumor that Whitbread is no longer
producing dry yeast, production stopped earlier this
year.

o I can also tell you that Red Star has been out of the
beer yeast production business since last year.

I've once or twice seen the question, "Who makes the dry
beer yeast that's private labelled by G.W. Kent?" Answer:
Lallemand Inc., who are known for their 70+ strains of dry
wine yeasts, usually under the "Lalvin" trade name.
They now produce both a lager and an ale dry beer yeast, at
plants in Canada and Denmark.

This information comes from the owner of G.W. Kent Inc., a
major brewing and vinting wholesale supplier, and the U.S.
Agent for Lallemand. Some highlights from Lallemand
marketing literature they shared with me:

Until the 70's, the wine industry all used spontaneous
fermentation. About that time, experimentation began on
isolating single cell cultures that would provide
individualized and consistent characteristics. Single cell
strains were successfully isolated, but there were problems
developing commercial cultures. This was due both to
limited culture lifespan and short unpredictable grape
harvest seasons.

If you use dried yeast for brewing, you may be interested in
these rehydration recommendations from Lallemand:

"Three factors seem responsible for the effects of
rehydration on subsequent activity. The first is a
loss of cell constituents, which results in poor growth
and activity. Secondly, improper rehydration creates a
condition of poor dispersion of cells which results in
clumping of cell groups thereby reducing the efficiency
of oxygen and nutrient transfer to the cells. The net
result, poor activity. Finally, the effect of "cold
shock" can also be devastating. When dry yeast is
added to cool must, water or wort, the viable cell
count can drop by as much as 60%! Petite mutants can
be formed which may produce off flavors. Although
these mutants generally have a limited life during
normal fermentation, their effect can be magnified
because of the sluggish nature of the remaining
recovering cells."

Guidelines:

o Use 5-10 times the amount of water to dry yeast.

o Use water between 105-114 F.

o Add yeast to water, not water to yeast, to avoid
uneven rehydration.

o Let the yeast sit for 5-10 minutes before
stirring, and pitch within 30 minutes.

o If your wort is over 50 F, gradually add small
quantities of wort to the rehydrated yeast, in 5
or 10 minute intervals, to allow for temperature
matching.

o Rehydrate in water, not wort, due mainly to wort
components that are lethal during the rehydration
period, such as SO2 and hop components.

In summary, Lallemand dry yeasts are selected for
fermentation characteristics (as well as dehydration
survivability), and they recommend rather more complicated
rehydration procedures than the published homebrewing
literature I've seen. It is possible that many of the off
flavors I've had over the years of brewing with dry yeast
came from improper pitching technique, such as opening the
package and dumping the dry yeast directly into my wort.

I hope you've found this information helpful.

Disclaimer: I've never used Lallemand yeast, and for the
last 18 months have been using nothing but liquid cultures.
I don't plan to go back.

- -----------------------------------------------------------------
Josh Grosse jdg@grex.ann-arbor.mi.us

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