Temp reduction suckback - Let's brainstorm

[bierhaus15]

Seems like your all looking for a complex answer to a simple problem. Take it or leave it, but when I am cold crashing or conditioning I take a party balloon, sanitize it with starsan and then put it over the mouth of the carboy. No O2 gets in, the balloon inflates/deflates with the temp fluctuations and no worries. Simple.

 

[johnnybrew]

Seems like your all looking for a complex answer to a simple problem. Take it or leave it, but when I am cold crashing or conditioning I take a party balloon, sanitize it with starsan and then put it over the mouth of the carboy. No O2 gets in, the balloon inflates/deflates with the temp fluctuations and no worries. Simple.

I like this approach the best. Low tech, effective and simple. I think if there is going to be a large change in pressure you could always inflate the balloon with some CO2 prior to putting it on top of the carboy. Either way, this is a perfect solution. Cheers, bierhaus!

 

[dstar26t]

The regulator is set as low as it goes and the carboy caps are zip-tied so there are no leaks.

 

[Bensiff]

Why even bother putting a blow off tube in a jar of water, just run it into a dry jar. Bugs aren't going to go flying up the tube to infect the beer unless you have a fan blowing air up the hose. Oxidation is a minimal concern if you are brewing something that will be consumed in a short amount of time. If you are going to brew something for long term aging then it starts getting worth all the effort to keep oxygen at bay.

 

[Douglefish]

So just as a note, I went to keg my Union Jack Clone this morning and found that the StarSan had been sucked up a 10 foot, 1/2" ID tubing into my fermenter after cold crashing. I couldn't figure out how it happened and then it hit me.

I cold crashed to 0 degrees C, and of course the StarSan froze in the growler I had put the blowoff tube in. I knew I was going need the growler so I set it, with the blowoff tube, outside the chest freezer. Apparently, when the starsan froze, there was a vacuum inside the fermenter and when it thawed it was sucked into the fermenter. I may be crazy, but it looks like there was at least a pint sucked in.

I tasted it and it seems great, but does this make sense to anyone?

 

[scottland]

There is such a simple solution to this problem -- replace your airlock with a stopper. Once you start cold crashing, you can think of your fermentor as on big corny, so just put a stopper in there, and call it a day.

 

[wilserbrewer]

People really need to quit over engineering everything...

Yea man, I ferment and then cold crash in a stainless kettle w/ the lid on...I figure once you are down to cold temps, neither oxygen nor stray bugs are altering the beer. I don't brew anything that cellars around for any long periods....maybe I should?

 

[kevmoron]

http://morebeer.com/view_product/10937//Premium_Breathable_Silicone_Carboy_Hood%3Cbr__%3E


These things are amazing.

The advantage of this over an airlock is:

1) If cold crashing or otherwise subjecting the carboy to a cooler environment, airlock juice or air will not be sucked into the carboy. It will instead maintain the negative pressure gradient indefinitely to no detriment.
2) If you use it on a better bottle, picking it up and flexing the plastic will not suck in liquid.

There is another (cheaper) popular model of breathable silicone stopper, but this one has two more advantages:

1) It simply works better. I've used the other breathable stopper and it sometimes pops out with pressure rather than venting properly. This is especially problematic if the stopper or carboy neck is wet when you put it in.
2) It fits just about anything perfectly - glass carboys, better bottles, even 2 L flasks. One size fits all.

 

[petey_c]

"Once fermentation slows, sanitize a balloon (or unlubricated condom) and stretch it over the mouth of the carboy." Try my Safe Sex Lager!
All this talk about gas got me wondering about how much gas is generated during a typical ferment... Time for a search...
Now I'm picturing a condom in place of an airlock acting like one of these...
http://www.advertisingballooncompany.com/

 

[dstar26t]

Trying out this set-up. The 3 gallon carboy in the back left corner was sanitized and purged with CO2. It'll fill with CO2 and act as a reservoir for when cold crashing happens.

 

[Bobby_M]

Why even bother putting a blow off tube in a jar of water, just run it into a dry jar. Bugs aren't going to go flying up the tube to infect the beer unless you have a fan blowing air up the hose. Oxidation is a minimal concern if you are brewing something that will be consumed in a short amount of time. If you are going to brew something for long term aging then it starts getting worth all the effort to keep oxygen at bay.

I never assume that my brew will be consumed quickly. I've got like 14 kegs and 5 serving positions. Even session beers can hang around for 6 months and longer if I bottle a few. I think the easiest idea is to fill a mylar balloon with co2 and clamp it on the carboy cap just before setting the controller to 35F.

 

[Jawbox0]

If you really are worried about the conditions inside your fermentation chamber, rig tubing outside your chamber and either use a blowoff or S shaped bubbler with Vodka there. It'll suck a little outside air, but at least it won't be from inside the fridge. It might be a kind of cool decoration if you do it right.

 

[2bluewagons]

Why not take off the airlock completely and use a carboy cap or a solid bung? That's what I do..............

+1, place bung in while at rom temp, cold crash, then bring back up to room temp for keg transfer/bottling and bung will not be stuck like one poster remarked. That's what I do, but also do not cold crash too often and have yet to brew a lager.

 

[johnnybrew]

Here you go boys (and girls), the solution. That bad boy is getting tossed into the fridge behind for a 3-day cold crash. No worries of bugs now.

 

[dstar26t]

No worries of bugs but you're still pulling oxygen in.

 

[johnnybrew]

No worries of bugs but you're still pulling oxygen in.

Are folks that worried about exposing their beer to O2 for a few days? Is this really an issue?

 

[dstar26t]

I worry about it for beers I plan to age for a long time.

 

[jamest22]

Here you go boys (and girls), the solution. That bad boy is getting tossed into the fridge behind for a 3-day cold crash. No worries of bugs now.

Exactly. I do the exact same thing. Works great. I got the sanitary filters here: http://morebeer.com/view_product/16797//Sanitary_Filter

Also, the filters fit snugly directly into the drilled hole in a rubber stopper.

I have watched it happen and it is amazing how quickly and how much air the carboys will suck in while the beer is cooling. I ferment in a dirty old craigslist freezer also and I do not trust the air quality in that thing.

As far as concerns over oxidation during cold crashing, I figure that after primary fermentation there should still be a blanket C02 in the carboy, if you use the sanitary air filter before crashing it will suck in sanitary air but that should not seep below the C02 blanket too much should it?

 

[dstar26t]

When fermenting beer produces CO2, it dilutes the air in the head space, eventually diluting it to a point where it's basically all CO2. The air and extra CO2 has been forced out the airlock leaving a CO2 "blanket" over the beer. Once you suck air back in during crash cooling, it mixes with the CO2. Once they mix, they stay mixed. Gases in this example don't stratify like oil and water.

 

[RukusDM]

Maybe some folks have this all figured out and perhaps many others don't even know it's an issue. When you ferment at one temp and then reduce the temp later for any reason, you reduce the pressure in the fermenter pretty significantly. This can be trouble when cold crashing an ale or when ramping a lager down to 35 down from a diacytel rest.

If you use a bubbler airlock, you are certainly sucking the liquid in. If you use a medium sized blowoff into some liquid, you can definitely suck that back in too. My fermenting fridge isn't exactly a spotless sanctuary and I don't like the idea of that air nor oxygen getting into the fermenter.

My initial idea is to fill a plastic bag with CO2 and rubberband it over the blowoff tube (the end that is normally sitting in the starsan bucket). I'd do this right when I start dropping the temp. If I anticipate it properly, an alternative is to attach a deflated bag over the carboy neck as fermentation is still happening but winding down so that it fills with "free" co2 to be sucked back in during crashing.

Discuss.

Bobby, I've just recently brewed my first real lager. I noticed what you were talking about when the fermenter temperature dropped. I thought I didn't put in enough water in the airlock then it struck me what was happening.

I then tried emptying the airlock and re-installing it with no water in it until it sat for a couple hours. I then added water and didn't have a problem.

Do you think that short a time of exposure to air will cause issues? I know it might be a day before CO2 really starts to be generated, but that would happen anyway even if their wasn't suckback.

I've seen cans of CO2 sold at wine stores called Wine Saver. I might just get a can of that to have around to put a blanket on the top of the wort.

 

[Bobby_M]

I wouldn't worry about air getting in prior to fermentation. It's the cold crashing just prior to lagering or packaging where I don't particularly want ANY O2 getting in there.

I agree with dstar26 though... a CO2 blanket is an imaginary security blanket. CO2 and O2 don't repel each other, they play nice just like what happens in the atmosphere.

 

[johnnybrew]

I guess if you are concerned about O2 exposure you could modify the rig below to include a CO2 intake/supply. I would think that if you filled a balloon with CO2 from your keg setup and then attached the balloon to the other side of the filter, you would only take in filtered CO2 into your carboy as the temperature and pressure changed. To ensure the balloon didn't leak, a simple zip-tie would do the trick. Thoughts/feedback?

 

[jamest22]

Why not take a CO2 tank with the regulator set to 1psi and set it up to feed into the carboy through a hood/stopper. That way as the pressure drops in the carboy while crashing, CO2 will enter to keep it filled. (maybe someone has already suggested this, I haven't read the whole thread).

 

[Bobby_M]

I agree that a balloon filled with CO2 is a fine solution. I'd probably want to use something like a mylar O2 barrier bag so that the CO2 wasn't really under pressure.

 

[johnnybrew]

...I'd probably want to use something like a mylar O2 barrier bag so that the CO2 wasn't really under pressure.

Good idea. Might try this out on my next cold crash.

In the past, I used a balloon alone (as someone on this thread suggested). It worked out ok, but the amount that it was drawn back into the carboy was cause for concern. It was under a lot of pressure and could have easily gotten pulled into the vessel. I should have snapped a photo because the inflated balloon inside the carboy was interesting to see.

 

[Bobby_M]

5 gallon mylar water bag. I'd just chuck a drilled stopper into the opening. I bet you could run a hose from the side port of a carboy cap into here leaving the center one into a blowoff container and it would probably inflate just fine.

 

[seyahmit]

I sanitize some saran wrap and rubber band it tight around the neck of the carboy.

 

[SirBC]

I use the CO2 adapter at 1.5 PSI while crashing and then will dump trub and push to keg.

 

[bigbeergeek]

Clearly there's a dozen ways people deal with this "problem." I just use a long 1/2" blowoff tube. I attach the tube a couple of days before I crash, residual fermentation displaces the O2 from the line, and the suck-back is O2-free and no liquid gets into the carboy. It might very well be overkill, but at least it is straightforward, simple, and I didn't have to buy/rig-up anything new to do it. It's all equip. that every one of us already owns.

 

[johnnybrew]

Here's the latest version of the idea. Seems to be holding pressure ok. The parts are simple: a balloon filled with CO2 attached to a millipore filter. I used tape in places to snug up the seal.