On Sun, 15 Jul 2012 13:44:21 +1000, "Farm1" >
wrote:

>Does anyone know how compressed yeast (in a cake form and bought fresh from
>a refrigerated cabinet) is made?
>
>The reason why I am asking is that a lot of the old books dating from the
>19th C and the early 20th C which I own, give recipes that describe boiling
>unpeeled potatoes with hops as a way of making yeast. I am curious if that
>old method of making yeast is/was in any way similar to how modern
>compressed fresh yeast is made.
>
>I've tried doing a google search but failed miserably to turn up anything
>informative ont he subject.
>

That sort of yeast is commercially grown in vats, centrifuged, then
compressed.

You need yeast to make yeast...that is, you need to capture and
encourage its growth, or use a seed culture. Compressed yeast is S.
cerevisiae, so you would need to start with a pure strain of that.

It is easy to create a liquid yeast to use at home, but you'd have a
combo of S. cerevisiae or similar (depending on how you start your
culture) and lactobacillus, rather than a pure strain of S.
cerevisiae.

The centrifuging and compressing is mechanical and probably not easily
done unless you are a tinkerer with access to 2nd hand fancy lab
equipment you can tinker with in your basement or garage..and even
then...

Boron