Stalled brew

[Brewer #42226]

I don't do a lot of brewing, and my batches are often spread out over time. I have noticed I do get more stalled ferments than average and I've never been able to figure out why. Several days ago I put on an oatmeal stout kit, adding nutmet, vanilla extract, and almond extract. Things seemed to go fine for the first 2 days, when I got up the morning after I started it there was a nice couple inches of foam and the airlock was bubbling away happily. The next day there was nothing. I've run into this before (maybe 1 out of 3 or 4 batches stall) and have tried adding more sugar, yeast energizer, more yeast, all with limited success. This time I tried something more extreme: campden tablets to kill anything that might have gotten in my brew, let it sit 24 hours, and then added more yeast last night. It does seem to be very slightly activating, but not a lot of movement.
One of the things I started wondering about - I also do a lot of lacto-bacteria fermenting (saurkraut, kim chi, pickles, etc) and also kombucha. My work area is fairly small and I have an old farmhouse that's dry and dusty and a bit on the cool side. What would happen if the wort was cross-contaminated by one of these other cultures I use? Could that stall a yeast ferment? I've also noticed the stalls seem to happen more in brews I start in cooler seasons when the furnace is running and blowing the hot air around.
Unfortunately I'll be gone now to deer camp until sunday so I won't be around to watch what's happening with the brew or to be very involved in this conversation, but I wanted to get something written down and see what people had to say.
Thanks!
Tod

 

[Yooper]

In short, no- lacto infection won't stall yeast and instead will ferment also and sour the beer.

When your batches get stuck, what is the SG they tend to stall at?

 

[Brewer #42226]

I don't know, I've never gotten into the science of the brewing and don't measure the SG, trusting instead that the kits will have things close enough to where they will brew me a beer I enjoy.

A yooper huh? Me too. Ishpeming.

 

[GFHomebrew]

I don't know, I've never gotten into the science of the brewing and don't measure the SG, trusting instead that the kits will have things close enough to where they will brew me a beer I enjoy.

A yooper huh? Me too. Ishpeming.

1 there is the slightest case they could be done.
2 if you dont measure gravity you dont know fermentation is stuck.
3 i know them sour yeast dont like it too cold so im sure your yeast pitch should sort them.
4 oxygenation = better population growth =better final attenuation.

 

[Yooper]

I don't know, I've never gotten into the science of the brewing and don't measure the SG, trusting instead that the kits will have things close enough to where they will brew me a beer I enjoy.

A yooper huh? Me too. Ishpeming.

This is a silly question then- but without taking the SG, how do you know they are "stuck" and not simply done? My bet is that they are done.

Yep, I'm a Yooper also. I already filled my tag during archery season, but I'm sitting here having coffee right now and a buck just strolled through my front yard and down the sidewalk and across the street. HA.

 

[Brewer #42226]

In the past I've assumed they haven't been done yet because they didn't have an alcoholic kick to them. This time around the active period just seemed too quick, it's not a yeast that supposed to finish that quickly, especially in relatively cool house. I could be wrong - maybe a little bottling and testing is in order! *hic*

No deer here. Missed a nice 5 pointer - he came in about 15 minutes after I left to go back to the camp to warm up in the afternoon. I crossed his fresh tracks as I was walking back and had this sinking feeling....

 

[Yooper]

In the past I've assumed they haven't been done yet because they didn't have an alcoholic kick to them. This time around the active period just seemed too quick, it's not a yeast that supposed to finish that quickly, especially in relatively cool house. I could be wrong - maybe a little bottling and testing is in order! *hic*

No deer here. Missed a nice 5 pointer - he came in about 15 minutes after I left to go back to the camp to warm up in the afternoon. I crossed his fresh tracks as I was walking back and had this sinking feeling....

I have an 8.2% IPA on tap right now that is so smooth and tasty that it seems like 0 alcohol. The greatest beers don't "taste" of alcohol, nor do they have the kick of alcohol like a cheap rum.

A warm-ish fermentation in a beer can happen overnight- I've personally seen it happen that a beer will ferment out in 24 hours. That's not ideal, because it could easily get too warm and cause off flavors, but typically all of my beers ferment out in under 5 days, usually about 3. And I keep them at about 64 degrees, so it's not overly warm. Some do take longer, depending on the OG of the beer and the yeast strain and if there isn't enough yeast pitched at the beginning. But a lengthy fermentation generally means a problem with the technique, and is not typical.