From the HBD Archive
From: djt2@po.CWRU.Edu (Dennis J. Templeton)
Subject: Growth curves
Date: 1992-06-11 14:37:12 GMT

Brett Lindenbach wrote a great piece on the growth of yeast that deserves
repeating:

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!

(end)

I wanted to comment that this curve (when modified slightly) applies to
populations of people as well as yeast, though the time frame is expanded
significantly. Thus:

# |
P | ---------
E | +++ ooo
O | ++ oooo
P | + ooooooo
L | +
E | +
| ++
|=====
---------------------------------------
TIME
= lag phase The current earth situation contains
+ log phase geographic locales that fit all of these
- stationary phase phases, as shown below:
o decay phase


# | Calcutta
P | ---------
E | +++ ooo
O | ++ ^ oooo
P | + NY City ooooooo
L | +^ ^
E | + Phoenix Campden, N.J.
| ++
|=====
^
Antarctica
---------------------------------------
TIME

It should be noted that yeast also have a decay phase, and the junk at the
bottom of a well-aged bottle of home-brew more closely resembles
Campden than the Big Apple.


Back New Search

The posts that comprise the Homebrew Digest Searchable Archive remain the property of their authors.
This search system is copyright © 2008 Scott Alfter; all rights reserved.