From the HBD Archive
From: "Brett Lindenbach" <Brett_Lindenbach@qms1.life.uiuc.edu>
Subject: growth curve
Date: 1992-06-10 23:56:46 GMT

Subject: Time:5:55
PM
OFFICE MEMO growth curve
Date:6/10/92
John Cotterill asks:
>Whenever I use Wyeast, I prepare a 12oz starter. Timing when to pitch
a
>starter has always been a mystery to me. The general recommendation
is
>to pitch at high krauesen. The trouble is determining when high
krauesen
>occurs. With my starters, I am lucky to get 1/8 inch of foam on top,
and
>that is a best case! What sort of krauesen do you get, and at what
point
>do you pitch the starter?

John, the idea behind this is that you want to pitch when the yeast are
most active. Here's a quicky on how yeast (and other microorganisms)
grow (usually):
(monospace)

# |
| ---------
C | +++
E | ++
L | +
L | +
S | +
| ++
|=====
----------------------------
TIME
= lag phase
+ log phase
- stationary phase

High krausen will occur during mid- to late-log phase, evidenced by the
healthy head. During this period, the yeast is gorging on all that nice
sugar, and dividing rapidly. Consequently, it will be able to take over
the wort very quickly. Thus, the yeast will be happy, and risk of
infection minimized. Happy brewing!
:BDL




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