WTF happened??????

[enohcs]

So I was fermenting my beer in a converted fridge at ~68. I'm using a blowoff tube that went into a growler with sanitizer in it. Added some dry hops after primary was complete. Everything was going fine until I cold crashed. I dropped the temp to ~38. I check on it the next morning and all the sanitizer was sucked up into the fermentor, and I'm sure enough oxygen to totally kill it. I find this odd since I've made lagers in this fridge and never had this happen.

 

[bennie1986]

So I was fermenting my beer in a converted fridge at ~68. I'm using a blowoff tube that went into a growler with sanitizer in it. Added some dry hops after primary was complete. Everything was going fine until I cold crashed. I dropped the temp to ~38. I check on it the next morning and all the sanitizer was sucked up into the fermentor, and I'm sure enough oxygen to totally kill it. I find this odd since I've made lagers in this fridge and never had this happen.

If the temp change was rapid I suppose that could happen. At this point I would fill it back up and finish the beer. I bet it will be fine just drop the temp slower next time.

 

[kh54s10]

The change in temperature lowered the pressure in the fermenter so low that and maybe combined with high atmospheric pressure caused the sanitizer to be pushed/sucked into the fermenter.

Unless there was a very large amount of sanitizer sucked in, give it a chance. I have heard a lot of these stories where the beer was fine.

Did you have the growler with the sanitizer in a higher position than usual. I always keep the catch vessel as low as possible so it takes a lot to make a reverse siphon. I also only use a margarine cup in a pot with only 1 inch of sanitizer, maybe one cup. If I have suck back there is not much to be sucked in.

I would suggest an s style airlock or just a piece of foil when cold crashing. Or to lower the temperature slowly.

 

[EODstads]

you gotta also be careful when cold crashing too quickly because if you shock the yeast too much it can release esters that you may not want in your beer. Personally no more than 3 degrees per day is what I would recommend

 

[enohcs]

experiment underway. I have put 10gal of water in the 14gal fermentor. Water temp and fridge temp are both at 70f. I placed the blowoff tube in a 0.5gal growler, and marked the water level in the growler. I then set the fridge to 34f, and I am going to see where the water level is tomorrow. I'm then going to go back and repeat, but instead of crashing hard, I'm going to drop it by 5f/day to see how that may effect the water level in the growler.

stupid suckback...ruining my beer

 

[raouliii]

you gotta also be careful when cold crashing too quickly because if you shock the yeast too much it can release esters that you may not want in your beer. Personally no more than 3 degrees per day is what I would recommend

Do you have a reference for this claim? I've never read or heard this before.


I use an S style airlock to alleviate suck back during crashing. I use cheap vodka in the airlock and add a star san soaked cotton pad over the airlock during crashing.

I hypothesize that regardless of how quickly the temperature is dropped, the same amount of pressure equalization will be required between the interior of the carboy and atmosphere. This will require the same number of air bubbles to be sucked into the carboy, just over a different period of time.

 

[volktc]

Gas laws my friend. a decrease in temp caused a decrease in volume and pressure. since your blow off was in water you had a closed system thus created a vacuum and sucked up the liquid. same reason when they clean train cars with high temp wash they have leave the hatches open. crush em like a soda can if they dont

 

[EODstads]

Do you have a reference for this claim? I've never read or heard this before.

I use an S style airlock to alleviate suck back during crashing. I use cheap vodka in the airlock and add a star san soaked cotton pad over the airlock during crashing.

I hypothesize that regardless of how quickly the temperature is dropped, the same amount of pressure equalization will be required between the interior of the carboy and atmosphere. This will require the same number of air bubbles to be sucked into the carboy, just over a different period of time.

I recently read a yeast book written by the guy who operates white labs. Unfortunately I sent the book home already (as I am in Afghanistan) so I can't directly quote it but I am fairly certain that when I get home ill be able to quickly find the reference for you

 

[SpeedYellow]

This sanitizer suck-back story happens all the time. There's really little reason to immerse your blowoff tube, but clearly a lot of risk in it. Here's a simple idea: take an empty, capped milk jug and cut an undersized hole in the cap, then jam your blowoff tube into it, just a couple inches in. Don't need to use any sanitizer.

 

[FarmerTed]

Gas laws my friend. a decrease in temp caused a decrease in volume and pressure. since your blow off was in water you had a closed system thus created a vacuum and sucked up the liquid. same reason when they clean train cars with high temp wash they have leave the hatches open. crush em like a soda can if they dont

You get the pressure decrease, but also CO2 is more soluble in cold water than warm water, so the beer will start absorbing the CO2 blanket, which will cause more air to be pulled back into the fermenter than if just a pressure drop was occurring due to the temperature change.

 

[two_one_seven]

I recently read a yeast book written by the guy who operates white labs. Unfortunately I sent the book home already (as I am in Afghanistan) so I can't directly quote it but I am fairly certain that when I get home ill be able to quickly find the reference for you

"Yeast the practical guide to fermentation" Crish White and Jamil Zainasheff. It states that yeast are very sensitive to small temperature changes and that it can shock the yeast and the will express shock proteins that will cause off flavors in the beer.

 

[BradleyBrew]

it happens...it happened to me. About 16oz of santizer went back into the beer (Kolsch)... the beer tasted like beer with a reduced sour star-san taste. Contacted Five Star and they advised me to get rid of the beer and not by drinking it. Sucks but it happens. Now I just use a solid bung to cold crash and just "burp" it every 8 hours or so.

 

[Peppers16]

Using an S airlock instead of the cylindrical ones should prevent that happening. I'm sure the beer's fine though. Sucking a little oxygen into the headspace won't destroy the batch, and people have spoken about entire gallons of StarSan going into batches and the beer coming out just about drinkable.