I've been reading "BEER: Tapping into the Art and Science of Brewing" by Charles Bamforth (great read, by the way - lots of technical scientific stuff for us brew-nerds)
He has this to say about washing and storing yeast (on page 151):
"The yeast may also have picked up some contaminants in the fermenter, which must be gotten rid of. This can be achieved by washing the yeast for an hour or two in a solution of phosphoric acid at PH 2.2. Yeast survives this treatment quite happily, but bacteria don't."
Now, I know that Star San is roughly 50% phosphoric acid... but I also know it has a few other ingredients in there... my question is, if you really wanted to wash the bacteria out of the yeast, could you dilute the Star San to a PH of 2.2 and actually wash your yeast with that before putting the little guys to sleep in a mason jar?
Speaking of which, what is the PH of properly diluted Star San? I know that once it hits 1.7 or below, it stops being an effective sanitizer... I'm assuming it's over 3?
He has this to say about washing and storing yeast (on page 151):
"The yeast may also have picked up some contaminants in the fermenter, which must be gotten rid of. This can be achieved by washing the yeast for an hour or two in a solution of phosphoric acid at PH 2.2. Yeast survives this treatment quite happily, but bacteria don't."
Now, I know that Star San is roughly 50% phosphoric acid... but I also know it has a few other ingredients in there... my question is, if you really wanted to wash the bacteria out of the yeast, could you dilute the Star San to a PH of 2.2 and actually wash your yeast with that before putting the little guys to sleep in a mason jar?
Speaking of which, what is the PH of properly diluted Star San? I know that once it hits 1.7 or below, it stops being an effective sanitizer... I'm assuming it's over 3?