From the HBD Archive
From: "Brett Lindenbach" <Brett_Lindenbach@qms1.life.uiuc.edu>
Subject: scale up
Date: 1992-05-19 17:09:18 GMT

Subject:
Time:11:08 AM
OFFICE MEMO scale up
Date:5/19/92
js writes>> all the extra stages. I can't believe the yeast cares
whether it is in a
>> gallon of wort or an ounce.

bb replies>I don't agreee with this statement...i.e., If you dilute
>yeast too much, they seem to slow down
>more than proportionately.

While on this topic, I thought I'd bring up my experience. First, I
bring up active
cultures from single colonies (see my "too-scientific" yeast primer
from a few issues
ago). I have found that it is best to scale up gradually (ie. single
colony --> small
culture--> large culture, etc.). The reason is purely from the
perspective of
avoiding contamination. If you inoculate a medium with 1% active cells,
it has
a greater chance of outcompeting anything in that other 99% than if you
inoculate
with only .001%. This is a well established fact that is exploited by
people who
run fermentations (including non-alcoholic ones). Also consider that
most home-
brewers do not sterilize, but only sanitize their wort through boiling.
Thus, you
will be doing your yeast a favor if you give them a numerical advantage
over other
organisms. The bottom line: SCALING UP PRESERVES CULTURE INTEGRITY.
Hope this clears things up. Cheers!
-BDL





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