Beer suck back

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kev211

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So somehow my hefe that I brewed three weeks ago (has been at ~69-72deg) managed to suck back about 1/2 a gallon of star San water. Don't ask me how, I don't know and I'm not happy about it. About 5.5 gal batch. Question is... Am I good to keg/serve? Or is this beer toast? I don't wanna poison people drinking it haha. Standard starsan dilution rates. The blow-off tube was still submerged in solution so no risk for infection
 

bleme

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It might not taste great, but it definitely won't poison anyone. Chemically, it is very similar to Coke. You really have nothing to lose by kegging it up.
 
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kev211

kev211

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It might not taste great, but it definitely won't poison anyone. Chemically, it is very similar to Coke. You really have nothing to lose by kegging it up.
Huh. Interesting. Good to know. Pulled a sample and it actually tasted great so maybe a little starsan is the trick :D
 

grbrla12

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I have heard that starsan can become food for the yeast. I would add a week or two to your fermentation to help with that.
 
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kev211

kev211

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I have heard that starsan can become food for the yeast. I would add a week or two to your fermentation to help with that.
It was post fermentation and the gravity is 1.006 so I doubt I'm gonna get it to drop much lower.
 

bleme

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I have heard that starsan can become food for the yeast. I would add a week or two to your fermentation to help with that.
Starsan becomes yeast nutrient, but won't cause more fermentation in a finished beer. Only sugars can do that.

Pulled a sample and it actually tasted great so maybe a little starsan is the trick :D
By itself it tastes a little lemony, which should fit right in with a hef.
 

ba-brewer

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So have you figure out how it happened?
Was the container of starsan above the fermentor and it siphoned out?

The first time I dumped the air lock container of starsan into a fermentor I got a bit nervous at first, not sure what I would of done with a half gallon. Since then I am pretty sure I have forgotten to dump the quart or so of starsan I use to sanitize the inside of keg.
 
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kev211

kev211

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I have no idea how it happened tbh. Its in a chest freezer so it didnt evaporate. Its lower than the beer so it didnt siphon. And the lowest the beer got was ~67-68 and the highest was ~73. SS chronical. So maybe it was a perfect seal and the pressure change was enough to suck the starsan in
 

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You can get suck back if you lower the temperature after CO2 production (fermentation ) ceases, if the fermenter is air tight. Do you have full time temperature recording to know that your chest freezer didn't go a little bonkers one night? Amount of suck back is fairly easy to calculate if you know headspace volume, highest and lowest temps.

Brew on :mug:
 

Calder

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I assume the suck-back was thru a blow-off ...... otherwise that is one big airlock.

Just add enough starsan to cover the end of the tube in the future.

Starsan shouldn't be a problem.
 
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kev211

kev211

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You can get suck back if you lower the temperature after CO2 production (fermentation ) ceases, if the fermenter is air tight. Do you have full time temperature recording to know that your chest freezer didn't go a little bonkers one night? Amount of suck back is fairly easy to calculate if you know headspace volume, highest and lowest temps.

Brew on :mug:
I doubt it went bonkers. I don't record the temps but I do check them every morning and evening. Probe is in a thermowell and is pretty accurate. So I'm assuming if it fluctuated enough to suck it in overnight I would have noticed the low temp the next morning. I might look into temp recording though. Any suggestions?
 

AkTom

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I had that happen to me once... it was a hot, sweltering day. Ominous, dark thunder clouds overhead. The humidity was 97% and rising. I popped the top on a mean heffe. Just as I went to take a swallow. It sucked half my face into the bottle. I thought I was going to have a permanent duck face. YMMV
Cheers
 

doug293cz

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I doubt it went bonkers. I don't record the temps but I do check them every morning and evening. Probe is in a thermowell and is pretty accurate. So I'm assuming if it fluctuated enough to suck it in overnight I would have noticed the low temp the next morning. I might look into temp recording though. Any suggestions?
BrewPi or Tilt will both track and record your temps.

Brew on :mug:
 

ba-brewer

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I did some testing to see if I could turn a portion of my keezer into a lager fermenting chamber. I used plain water for my testing and found that I got much larger overshoot and undershoot of the temp if I used a thermowell vs measuring on the outside of the bucket. I think if I had an active fermentation going on that might not of happen. Toward the end of fermentation I think the fermentor might behave more like water so you might get bigger swings with a thermowell vs measuring the outside of the fermentor. If you have a cooling coil inside the fermentor that might behave differently.
 
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I did some testing to see if I could turn a portion of my keezer into a lager fermenting chamber. I used plain water for my testing and found that I got much larger overshoot and undershoot of the temp if I used a thermowell vs measuring on the outside of the bucket. I think if I had an active fermentation going on that might not of happen. Toward the end of fermentation I think the fermentor might behave more like water so you might get bigger swings with a thermowell vs measuring the outside of the fermentor. If you have a cooling coil inside the fermentor that might behave differently.
I'm using an SS chronical. I've tested at multiple stages of fermentation by physically sticking a thermometer into the beer and the thermowell is usually within 1 degree. I'm chalking this one up as a fluke/warmer fermentation issue.
 

kh54s10

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I see these types of posts quite often. I wonder why people that have 1/2 an ounce in their airlock feel they need to have their blow off tube in a gallon of sanitizer????

Put the sanitizer in a medium margarine tub to a level just enough to keep the end submerged.

The Starsan, if mixed correctly will not harm you. It will dilute the beer though.
 
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kev211

kev211

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I see these types of posts quite often. I wonder why people that have 1/2 an ounce in their airlock feel they need to have their blow off tube in a gallon of sanitizer????

Put the sanitizer in a medium margarine tub to a level just enough to keep the end submerged.

The Starsan, if mixed correctly will not harm you. It will dilute the beer though.
A. I only have the ability of use a blow-off. B. I usually just fill a gal jug to about 1/4 to 1/2 gallon. Nothing scientific, just fill it up. It's always done the trick til this once
 

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Hey guys,

I have a physics question: you're told not to close a glass carboy while cold crashing or the carboy will implode.

I saw that you can use an extra long blowoff tube so the suckbacked Star San doesn't make it's way all the way back to the carboy. But wouldn't that extra CO2 in the tube that gets sucked back do the exact same than sealing it completely off?
 

doug293cz

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Hey guys,

I have a physics question: you're told not to close a glass carboy while cold crashing or the carboy will implode.

I saw that you can use an extra long blowoff tube so the suckbacked Star San doesn't make it's way all the way back to the carboy. But wouldn't that extra CO2 in the tube that gets sucked back do the exact same than sealing it completely off?
No, the "sucked back" CO2 makes up for the drop in internal pressure caused by the drop in temperature. The gas law is PV = nRT, where P = absolute (not gauge) pressure, V = volume, n = the number of gas molecules, and T is temperature (measured on a absolute scale) and R is a universal constant. For a sealed container, V, n and R are all constant, so if T goes down, P must also go down. If you can suck back CO2, then "n" is no longer constant, so the pressure will not drop as much. In fact for typical blow off geometries, the pressure difference between the inside of the carboy, and the outside atmosphere will be much less than 1 psi. So, without the pressure differential, the implosion risk goes away.

Brew on :mug:
 
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