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stuck fermentaion & SNA

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ScottBehrens

ScottBehrens

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Premium Patron
Aug 26, 2012
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Vero Beach, FL
Have my first stuck fermentation after 15 years of beer and 2 years of mead. I was going to try to use the same yeast first, 71B after GoFerm rehrydration and add some must to get it started and pitch. May end up having to use a different strain but its all I have at the moment. Started 1.140 OG shooting for 1.040 FG. Used 5 G 71B originally and it stalled at day 5 at 1.094. In any case, do I start the SNA regimen again after repitching or is there plenty still in there since I did the DAP/FermaidK for 4 days already?
 
I add SNA with a measuring spoon 1/2 tsp DAP, 1/4 tsp FermaidK each addition for Days 0-4. The stall came later than day 5 once I looked at my notes. Brix is uncorrected. Fermentation at 62F with a thermowell and controller. I degas daily with a big spoon prior to any measuring. I have a dry in the same ferment fridge done on the same day that was treated identically and its 75% done. I am pretty new to mead, but here it goes.

Day 0. OG 1142 pitch temp 72F 5g 71B rehydrated with 6.25g GoFerm in 100ml RO water at 104F for 20 minutes. SNA right after pitch. O2 @ 2L/minute for 1 minute. pH 4.1

Day 1 1142 SG 32.9 Brix pH 3.92
Day 2 1139 SG 32.1 Brix pH 3.78
Day 3 30.2 Brix pH 3.67
Day 4 30.1 Brix pH 3.62
Day 5 1120 SG 29.2 Brix ph 3.55 added 10g Potassium Bicarbonate
Day 6 28 Brix pH 3.79
Day 7 1.094 SG 25.5 Brix pH 3.76
Day 8 1.094 SG 25.5 Brix pH 3.76
Day 9 1.094 SG 24.7 Brix* pH 3.77 *assume measurement error
Day 9 Added 5g 71B rehydrated as above (I think I will regret this)
 
Damn, good record keeping.........

Much more organised than me :D

Without knowing the weights for your nutrient amounts it would be difficult to be analy accurate but it doesn't look too bad at all, certainly not shockingly low (DAP provides 200ppm nitrogen per gramme per litre of must and fermaidk provides about 120ppm per gm/ltr - my blog has a post to an article from Zymurgy mag, written by Ken Schramm that details the right sort of levels - but from memory about the 300 to 350 ppm I prefer to mix 2 parts fermaidk to 1 part DAP as the must gets more of the non-nitrogen elements).

Anyway, the only obvious thing off the top of my head would be to check the temp levels that 71B is happy at (google the Lalvin yeast chart - sorry, don't know how to link from this smartphone). I'm thinking it might need to have a damned good areation and then bring the temp up to the low 70's as 62 might be a little cool......
 
Thanks I will check out your blog. I hadn't read about additions by weight. The record-keeping keeps me off the streets at night. Thank you for your help.
 
I've always been under the impression that the higher the starting gravity the more oxygen you need over a longer period of time. Not much help at this point, perhaps, but at your starting gravity I'd have been adding oxygen for the first four days at least, once a day. My meads tend to end up on the high ABV side that way, but I like them that way. I don't know when the latest is that you want to add oxygen, but I usually cut it off no later than my last nutrient addition.

Sorry I can't be of more help for getting things going again -- you're doing just what I'd be trying by adding another pitch of yeast that's at its peak activity. 71B should be good for 15-30C. You're at the low end of that range, but still inside it. Did you cool the must off suddenly enough to shock the yeast perhaps?
 
I have used pure O2 in the past at each nutrient addition and was also degassing with a spoon followed by a plastic wine paddle in an drill for about a minute. Several done this way seemed a little off. This time I gave it O2 at the start only and then thinking my drilling supplied the rest. I pitched at 72F and dropped in the fridge to 62F overnight. One of the podcast greats (cant even remember who now) mentioned he did all his 71B at 62 so I thought I would try. I am bringing it up a few degrees. We will see. Thank you.
 
kernel crush said:
Should I start a new SNA regimen or just leave it alone?
Click to expand...
I'm actually curious to hear folks' thoughts on this as well, as I may be faced with a similar situation soon myself.

A quick google search reveals advice from people in both camps. I personally would think that the new yeast would need nutrients and oxygen to reproduce and build a new colony just like the old yeast. But on the other hand, adding more nutrients than are necessary could leave some available for other undesirable microorganisms, and we certainly don't want more O2 in there than would be needed.
 
Schmafty, I just went ahead with a full new schedule like the first one never happened, figuring the benefit would outweigh the risk of doing nothing.
 
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