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Boogaloo
04-19-2012, 10:11 AM
What is the optimum PH for yeast to thrive in? I've looked all over the interwebs and am consistently getting different numbers. Some say 5.5 others say 7.5. Also, is the PH the same for the Must?

Any help would be great. Searched the forum for a yeast ph thread and found none.

Boog

Chevette Girl
04-19-2012, 10:52 AM
Yeah, the forum search tool won't be able to do a search on pH, not enough letters. Did you try acidity/acid or maybe the phrase "ideal pH"?

Boogaloo
04-19-2012, 11:00 AM
Ahhhhh.... I did not know the search function accepted the quotes like google does. Thanks for the tip!! I found a good thread in the Patrons area.

It seems yeast does well at 5-5.5 but if you get it to 3.4-4 it will help prevent spoilage and have a better mouthfeel.

Chevette Girl
04-19-2012, 11:27 AM
Well, if you didn't find the one on gluconolactone (I think it's by Dan McFeely), you should hunt it down too, it explains why you don't necessarily want your must to START at 3.4... most fermentations will cause a drop in pH, moreso with honey. I wonder if the yeast manufacturers' websites would be able to tell you the optimum pH for starting your yeast...

TAKeyser
04-19-2012, 11:51 AM
It seems like your interweb search is giving you results for both Beer Wort (around a 5.2 PH) and Mead Must (3.6 - 4.2 range). In truth when I make an actual starter I don't even bother checking PH and making starters are a regular practice for me with all of my melomels. If I was forced at gun point to check the PH I would want my Starter to be in the same optimum range for what I was about to ferment.

akueck
04-19-2012, 01:58 PM
Unless whatever you're fermenting is strongly buffered, the yeast will drop the pH down to a level that is good for them. Generally you don't have to worry that much about pH unless you've got a traditional mead (no buffering, can crash the pH) or lots of additives with very low pH (lemons, etc).

Beer worts start and end at higher pH than wine/mead musts. You'd think this would be bad for spoilage since pH<4 keeps a lot of nasties at bay, but the addition of hops or other herbs makes the beer wort antimicrobial even at a higher pH. Neat!

Boogaloo
04-19-2012, 02:09 PM
Unless whatever you're fermenting is strongly buffered, the yeast will drop the pH down to a level that is good for them. Generally you don't have to worry that much about pH unless you've got a traditional mead (no buffering, can crash the pH) or lots of additives with very low pH (lemons, etc).

Beer worts start and end at higher pH than wine/mead musts. You'd think this would be bad for spoilage since pH<4 keeps a lot of nasties at bay, but the addition of hops or other herbs makes the beer wort antimicrobial even at a higher pH. Neat!

Hmmm... is this the reasoning behind over hopping beers for long transport back in the day? (IPAs)

So let me see if I understand. The yeast will drop the PH to a level that is good for them, so if I add something to lower the PH the yeast will actually pull the PH too low?

akueck
04-19-2012, 02:22 PM
Hmmm... is this the reasoning behind over hopping beers for long transport back in the day? (IPAs)

So let me see if I understand. The yeast will drop the PH to a level that is good for them, so if I add something to lower the PH the yeast will actually pull the PH too low?

That's one theory I've heard for IPA. By the time a "regular" beer got to India, it had spoiled. Super hops to the rescue! [although historically these IPAs were not very bitter due to the long aging.]

There are lots of examples of people using older recipes that call for acid additions up front. Very often the pH drops too low for the yeast to operate and the fermentation stalls. For this reason it's recommended that you don't add any acid until and unless the mead actually needs it (e.g. for flavor after fermentation is complete). Usually the pH will drop quite a bit in the first 24-48 hours of fermentation, just by yeast action alone.