Professional brewing yeast storage

Q#1:
I acquired a mason jar full of yeast off of a fermenting hefeweizen at my favorite brewery. The brewer that helped me steal a sample out of the fermenter advised me to not let the yeast drop below 50 degrees F because, and i quote, (he was kind of a tweaker and not very specific in his explanation) "the yeast just wont be right." The temp outside was about 32 degrees F so he told me, even on the short walk to my truck, to keep the yeast in my jacket pocket.

I was worried that if I didn't keep the yeast somewhere around 60F I would ruin it, but then I thought about when I buy yeast from the store, it's in the fridge. The avg. fridge temp is 40 at most. So i got home and just put the jar in the fridge. It just struck me as odd that the yeast could somehow produce an "off flavor" if it got too cold. I thought i would only need to worry if it got too warm. I thought yeast just went dormant when it got too cold... Does anyone know what this guy could have been talking about?

I just made a starter with the stuff today to keep it fresh and it looked and smelled exactly like it did when i got it. I'm not worried about it, I'm just curious to know why this guy would advise me about the cold and not the warm.

Q#2
I just kegged and bottled a Bitter Chocolate Oatmeal stout. I had some issues with a stuck fermentation b/c the O.G. was 1.096. I used White Labs Dry english Ale yeast. It stuck at 1.032. I was told by my local brew store to add White Labs High Gravity Ale yeast and just rack it and cold crash it when it got to the gravity I wanted. (F.G. 1.022) I did, then I bottled and kegged it.

My problem is that I went to poor a glass out of my 3 gal keg w/ picnic tap after a 4 week condition it was all foam. The funny part is I hadn't hooked up the CO2 b/c I wanted to see if the carb level was ok where it was at. I went to burp the keg (still with no CO2) and beer spewed out of the blow off valve. I decided to open the lid of the keg and when I did a volcano of foam would not stop erupting. I decided to grab a bottle of the same stuff and again after opening the volcano of foam was back. This was especially odd b/c I only added 1/4 of the priming sugar that I should have when I bottled. The Beer tasted wonderful once the foam settled, and honestly it doesn't taste over carbed.

Any ideas on what happened? I wanna blame the high gravity yeast but I really don't know what the culprit is.

Hiccup...

Q1. That dude is crazy. A lot of people in this hobby/profession do things by convention. Someone else did it that way so it must be the only way to do it. If you spend some time on the probrewer forums you'll see that a lot of the brewers say they should have gotten a degree in microbiology. Of course that means that most of the people in brewing don't have a degree in microbiology. I'm not a microbiologist either but I am studying biomedical engineering so I have some background in it. As long as the water in and around the yeast cells doesn't begging to crystallize (ie. turn into ice and puncture the cell membranes of the yeast) a colder temp is not going to Hirt your yeast. It will actually help them by slowing down their metabolism and this preventing them from starving. And even freezing your yeast is possible if you take precautions to prevent ice crystals.

Q2. Your yeast kept eating sugar and making CO2. If those were bottles you would likely have made bombs. If you are going to try to stall fermentation to achieve a specific gravity you'll really need to keep your beer refrigerated to prevent it from resuming fermentation after warning. Yeast is much more resilient than people give them credit for. They haven't been around for thousands of years thanks to us.

TarheelBrew13 said:

Q2. Your yeast kept eating sugar and making CO2. If those were bottles you would likely have made bombs. If you are going to try to stall fermentation to achieve a specific gravity you'll really need to keep your beer refrigerated to prevent it from resuming fermentation after warning. Yeast is much more resilient than people give them credit for. They haven't been around for thousands of years thanks to us.

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Great! Bottle bombs! The old lady will be thrilled if those explode in the dining room. They are promptly going in the fridge. Ida thought 4 weeks would have been enough for them to explode if they were guna.

Q#3: How long does it take for bottle bombs to explode? lol...... ****.

They usually take several weeks. I have a brewing buddy that refused to listen to me and insisted on bottling when his beer hit the estimated FG from beersmith. He forgot to correct his hydrometer for the temp in his home and really wasn't all that close. I don't remember exactly how long it took but it was more than 4 weeks. He said it sounded like a drive by shooting (he lives in a bad neighborhood) when several of them exploded. I had a similar experience with a Pumpkin Ale I did when I first started brewing. I was too anxious to drink it and bottled too early. That was not good.

You can vent your bottles to prevent their eminent explosion by prying the cap up slightly. If you do it only a small amount the cap will undergo what is known as a elastic deformation and return to its original shape when released. This allows some of the CO2 to escape. You'll know if they are overcarbed when you do this by listening to a faster than normal hiss from the bottle followed by a lot of foam production. If you do let the foam settle and then repeat 2 to 3 times you can bring a gusher down to normal carb levels and disarm your homemade grenades. Or keep them around for the Zombie apocalypse, your choice. A similar procedure could be used on your kegs.

As a side note, if you know your recipe really well, you can use this phenomenon to carbonate your beer without adding priming sugar by simply transferring your beer to kegs/bottles just before it reaches its terminal gravity. This is even easier if you artificially halt fermentation by cooling (ie: transfer the beer to the fridge when it reaches the SG you desire.) That's how one of my local breweries carbonates all their beer.