Check my math? Please?

How are you fermenting?

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mchrispen
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Re: Check my math? Please?

Postby mchrispen » Tue Oct 11, 2016 11:40 am

Comment on my process?

For still fermenting beer, I take a small sample from my zwickle port into a 50 ml beaker - discard, then rinse the beaker in distilled water. Pull a second sample. I will do a quick count to determine if I need to dilute to count (usually do during early active fermentation). If not - then I count using the usual 5 square counting. I tend not to worry about viability at this point, but it would be easy to add in a blue stain step.
Techbrau
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Re: Check my math? Please?

Postby Techbrau » Tue Oct 11, 2016 9:11 pm

It may be tricky to hit 15 million cells per ml at racking (i.e. about the same cell density you had at pitching) but I think it's possible to get close. I think it's very important to carry as little yeast over into the lager keg as possible, because over the course of a couple months I've gotten low levels of autolysis after carrying too much yeast over (confirmed via rising pH measurements over time). The funny thing is that the autolysis didn't result in the marmite or soy sauce flavor, but instead it damaged the fresh malt "it" flavor.

My current process is to pitch at 6c, ferment at 9c until 1% extract remains, drop to 6c over 1-2 days, hold at 6c for 1 more day, then rack. At this point I have about 0.3-0.5% extract left and most of the yeast has gotten knocked to the bottom of the fermenter and can be left behind - the beer is cloudy in the glass but clear enough to read through in the liquid transfer line.

The only way I can get the above to work is by capping the primary when I start the temperature drop. Without a primary fermenter that can handle pressure, I think it may be better to ferment to terminal gravity in the primary, let most of the yeast drop, and then add some fresh wort, sugar, or krausen beer when you rack.
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Weizenberg
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Re: Check my math? Please?

Postby Weizenberg » Wed Oct 12, 2016 3:44 am

There are other reasons for pH rises. I doubt it was autolysis if you didn't get the flavours.

That could be a red herring.

Thus said, keeping beer on the yeast at such high temperatures, will eventually cause autolysis.

I wonder whether there is a simple lab test one can perform to confirm this?
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Techbrau
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Re: Check my math? Please?

Postby Techbrau » Wed Oct 12, 2016 8:28 am

I saw the pH go up to ~4.6. What else would explain that?
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Weizenberg
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Re: Check my math? Please?

Postby Weizenberg » Wed Oct 12, 2016 4:58 pm

IIRC Annemueller lists thermal stress as another possible cause.
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Re: Check my math? Please?

Postby Weizenberg » Wed Oct 12, 2016 6:02 pm

There is also the effect of pH increasing once secondary fermentation isn't complete (Annemueller again).

However, a rise in pH does potentially signal autolysis. My point is that it's not necessarily the only cause, especially since the typical autolysis off tastes didn't happen.

Phase 2 is indeed a strange animal ;)
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mchrispen
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Re: Check my math? Please?

Postby mchrispen » Wed Oct 12, 2016 9:43 pm

Autolysis, at least when used sur-lies in wine and mead, will release buffering compounds. Fermaid O is a processed autolyzed yeast used as a nutrient in mead... it will buffer as much as 0.2 pH units, and releases slowly.


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