Help! - Cold crashed and sucked back blow off liquid...

[keelanfish]

Brewed a 12 gallon batch of weiss bier a few weeks ago. Fermentation was done in a 15.5 gallon Sanke, converted using Derrins equipment, and in a fridge at 62 degrees f. Vigourous and long fermentation as evidenced by amount of bubbling in the blow off container. When fermentation was complete, plus some, I turned the fridge down to 32 to cold crash late last week. Yesterday, when I checked, all of the liquid from the blow off container was gone and it appears it has been sucked back up the blow off tube into the beer. The blow off container is a 1/2 gallon glass growler (clean) filled half way with fresh star san.

First, should I even attempt to bottle this beer, or is it a gonner?

Second, I'm looking for easy ways to prevent this from happening in the future. So far my solution involves a backflow preventer (check valve) and a sterile air filter. Any easier solutions?

[snowcapt]

On page 23 of "How to Brew", Palmer writes about intentionally leaving tons of foam in the carboy to see what it did. "Fermentation, flavor, and head retention of the beer were fine"
I wouldnt worry too much about it, but like you said, take preventative measures. You will find out either way right?

[CRBrewHound]

It should be fine, bottle it.

[keelanfish]

Okay, so I'm going to go ahead and bottle this beer tonight and I'll of course take a sample to measure the gravity and taste. Hopefully it will taste fine and there will be no worries. Just a little freaked out by a quarter gallon of starsan being in the beer.

Regarding how to prevent this, what are some simple ways used by the people on this forum? If I replaced the blow off tube with a three piece airlock prior to cold crashing, would that prevent this suckback?

[snowcapt]

Okay, so I'm going to go ahead and bottle this beer tonight and I'll of course take a sample to measure the gravity and taste. Hopefully it will taste fine and there will be no worries. Just a little freaked out by a quarter gallon of starsan being in the beer.

Regarding how to prevent this, what are some simple ways used by the people on this forum? If I replaced the blow off tube with a three piece airlock prior to cold crashing, would that prevent this suckback?

Nope, it will still suck back, just not as much. Try using more hose and put your blow-off vessel way lower. Thats what I would try, anyway. Ther's my $0.02

[spiderwrangler]

I haven't seen it mentioned here, but the easier ways to prevent 'suckback', is to reduce the size of the headspace you have in your fermentor. The beer will expand and contract very little with changes in temp, but the air in the headspace will change drastically. If you have a fermentor that is very close to being full, the contraction of the air in the headspace will not pull much at all.

[CRBrewHound]

One thing you can do is just not use either blow off tube or airlock, simply place aluminum foil over carboy or pail hole and loosely secure in some way. Realistically you don't need anything during active fermentation, not even a lid. As the active fermentation and pour off of CO2 prevents entry of hazardous bacteria or yeasts. It is after the ferementation slows that you have the problem.

Even then I have heard people far smater then I saying that you don't need anything unless you are planning long term storage of the beer in a container (like several months).

[Elbone]

A one-piece airlock will not allow the vacuum to suck liquid back in.