[punatic]

I'm making a traditional mead using Lalvin 71B 1122 for the yeast.  I'm noticing that the fermentation slows quite a bit when the pH goes below 3.6.  I adjust the pH upward to 4.6 using a few mL of 8N KOH and fermentation takes off again.

Has anyone else observed this high lower limit to 71B's working pH range?  Are there specs for optimum pH ranges for individual yeast strains available anywhere?   I know there are general guidlines for mead pH, but It seems that some yeast don't know about those guidlines.  

[jaybeerman]

but It seems that some yeast don't know about those guidlines.   

just do your best to educate those dumb bast#rds

http://www.lalvinyeast.com/images/library/71B_Yeast.pdf  
You might show them this chart for titratable acid metabolism by strain

What strains do you take below ph3.6, just curious?  The chart is pretty limited, but I hope it helps with your questions.  cheers, j

[punatic]

Thanks for the link.  I've seen that spec sheet before, but I don't know of a correlation between the ability to metabolize acidity and low pH tolerance.  Perhaps the ability to metabolize acidity comes from not being able to tolerate low pH.

I had been using the following Wyeast strains for meadmaking:  4184, 4242, 4783, and 2124 (yes 2124).  They seem to be tolerant well into the low pH 3 range. 

I've been experimenting with dry strains lately.  I like their ease of use, but is the trade-off for this ease of use the need for closer pH monitoring?

[jaybeerman]

Thanks for the link.  I've seen that spec sheet before, but I don't know of a correlation between the ability to metabolize acidity and low pH tolerance.  Perhaps the ability to metabolize acidity comes from not being able to tolerate low pH.

I had been using the following Wyeast strains for meadmaking:  4184, 4242, 4783, and 2124 (yes 2124).  They seem to be tolerant well into the low pH 3 range. 

I've been experimenting with dry strains lately.  I like their ease of use, but is the trade-off for this ease of use the need for closer pH monitoring?

Thanks for the strain list, I'd like to hear more about your use of 2124. 

I think this is a correct statement - As the titratable acidity was metabolized you would see a general rise in the ph.  So - I think this is a correct statement - that should mean that 71b has a somewhat good low ph tollerance.  I know there's a million factors to consider, but I think there's somewhat of a corelation.

Interesting stuff for sure.  cheers, j

[punatic]

Thanks for the strain list, I'd like to hear more about your use of 2124. 

I think this is a correct statement - As the titratable acidity was metabolized you would see a general rise in the ph.  So - I think this is a correct statement - that should mean that 71b has a somewhat good low ph tollerance.  I know there's a million factors to consider, but I think there's somewhat of a corelation.

I wanted to make a lower alcohol sweet mead without stopping fermentation or back-sweetening.  I had some 2124 (it is my mainstay lager yeast), so I threw it into a low gravity traditional mead, fermented at 68F, and it worked really well.  The honey characteristics are highlighted.  Pretty neutral on yeast characteristics. Specs say 9%,  I get 11% in my meads.

Those wily Germans...

I'm thinking that maybe because a yeast like 71B has a low tolerance to low pH it evolved to metabolize acids to keep the pH from dropping too low... ?

Ken? Jamil?  Tom?  Are you in there?

[tschmidlin]

I'm thinking that maybe because a yeast like 71B has a low tolerance to low pH it evolved to metabolize acids to keep the pH from dropping too low... ?

Ken? Jamil?  Tom?  Are you in there?

It's possible.  Most yeast are able to metabolize various organic acids to some extent, so that some would do so better than others isn't a surprise.  This yeast was selected as good at fermenting grape juice, and the different composition of the honey will get you different organic acids during fermentation.  The pH will drop lower too.

So what I'm trying to say is, it is possible that the yeast is better at metabolizing acids typically created during wine must fermentation, and it's possible that those same acids are not the ones responsible for dropping the pH during a honey fermentation so the yeast isn't able to stop the pH from dropping too low for it to continue fermenting.

But I haven't done any experiments with this yeast except fermenting cider with it a couple of times.

[jaybeerman]

I wanted to make a lower alcohol sweet mead without stopping fermentation or back-sweetening.  I had some 2124 (it is my mainstay lager yeast), so I threw it into a low gravity traditional mead, fermented at 68F, and it worked really well.  The honey characteristics are highlighted.  Pretty neutral on yeast characteristics. Specs say 9%,  I get 11% in my meads.

Good info.  I like the idea of low alc mead; I've applied the idea to braggot but not to traditional mead.  I've found Scottish yeast to work well with braggot (up to 14%).  Now I'd like to use beer yeast to get a stable, delicious mead and/or braggot at around 5-6% alc.  cheers, j

Oh yeah...in a wine the general ph rise from acid metabolism is pretty minimal (even though 71B is way more useful comparatively speaking) so maybe the effect wouldn't even be noticeable in mead or like Tom said maybe it's not applicable to the acids in mead.  Wish i knew more about this stuff.