Easy suck back proof airlock set up

[MHBT]

Not taking credit, not my idea, but just an easy way to prevent suck back of sanitizer /oxygen when you cold crash..this is my first run gonna see how she works..just 2 ball jars and some hose

 

[BeeredCalavera]

Use just two mason jars with one filled halfway with sanitizer and works fine

 

[jack13]

I don't know why there would be, but it looks like there IS, liquid in the airlock. Is that the case?

But my main question is: How/why does this work to prevent suck back? I'm intrigued...

 

[mongoose33]

If you use an S-shaped airlock, there shouldn't be any suckback.

I've used the mason jars in the ferm chamber thing--moved away from that when, after I crashed the beer to 32, I discovered the sanitizer in the jars had frozen.

Now I send the CO2 out of the fridge into the jars on a bench next to the fridge. I pass that gas (yeah, I Know) out of the refrigerator through a bulkhead shank installed in the side of the refrigerator. That's with the big refrigerator. The small one I pass the lines directly through the top through a couple of holes I drilled and used rubber grommets to line.

 

[JONNYROTTEN]

A vendor here sells one of those setups.

Curious why you have wood separating the chest freezer?
Why the carboy in a milk crate with rags?

 

[Marcale]

Why such complex airlocks?
The main issues are twofold, having enough space for a vigorous fermentation and ingress of contamination.
I don’t use airlocks. I do my primary fermentation in a 40L loose fitting screwcap lid (originally Calcium Hypochlorite for pool HDPE container), once this has calmed down (SG about 1.012) it goes into a 20L vessel with a rubber glove with a pin prick 10 days in there finishes it off and clarifies (see photo of trial of 10L of extract).
Finally into Corny for conditioning prior to drinking. Careful siphoning and liberal use of CO2 minimises oxidation during transfers.

 

[mongoose33]

Why such complex airlocks?

The reason I originally did this was to provide a reservoir of pure CO2--that produced by the yeast--that could be drawn back into the fermenter when I cold-crash it.

I've also used a bread-bag method where I squeeze all the air I can out of a breadbag then fill it with CO2 from my tank. I then use a twist-tie to tie it off over the airlock, so crashing will suck back gas from the bag, not the atmosphere. Not perfect, but not bad.

I'm heading toward finishing fermentation in a keg which will naturally carbonate the beer as well as use up any O2 that happens to be in there. But in the meantime, I use my 2-vessel airlock system. It works.

 

[MaxStout]

Why such complex airlocks?
The main issues are twofold, having enough space for a vigorous fermentation and ingress of contamination.
I don’t use airlocks. I do my primary fermentation in a 40L loose fitting screwcap lid (originally Calcium Hypochlorite for pool HDPE container), once this has calmed down (SG about 1.012) it goes into a 20L vessel with a rubber glove with a pin prick 10 days in there finishes it off and clarifies (see photo of trial of 10L of extract).
Finally into Corny for conditioning prior to drinking. Careful siphoning and liberal use of CO2 minimises oxidation during transfers.

Looks like a lot of work to avoid using a $2 airlock.

If you really want to go simple, put a tinfoil cover over the mouth, held in place with a rubber band. Gas can escape and take air with it. Germs won't go in.

 

[murphyslaw]

I thought I read somewhere on here that the volume of air that gets sucked back is a lot more than the volume of the mason jars.

 

[MHBT]

I don't know why there would be, but it looks like there IS, liquid in the airlock. Is that the case?

But my main question is: How/why does this work to prevent suck back? I'm intrigued...

both jars get filled with co2 and when you drop temps it pulls the co2 back to the fermenter and sanitizer gets pulled from one jar to another but no liquid makes it up the blow off tube

A vendor here sells one of those setups.

Curious why you have wood separating the chest freezer?
Why the carboy in a milk crate with rags?

The wood board has a space hear pad adhered to it so i can remove as needed, the carboy in the crate makes it easier to pick up and the rags are covering the insulation for the controller probe.

 

[MHBT]

I thought I read somewhere on here that the volume of air that gets sucked back is a lot more than the volume of the mason jars.

probably, but this should definitely reduce o2 exposure

 

[MHBT]

Use just two mason jars with one filled halfway with sanitizer and works fine

Thats exactly what this set up is

 

[MHBT]

Looks like a lot of work to avoid using a $2 airlock.

If you really want to go simple, put a tinfoil cover over the mouth, held in place with a rubber band. Gas can escape and take air with it. Germs won't go in.

I used to do that with the foil, this is not alot of work 2 holes in each jar with some tubing..i prefer to have little to no air getting in my fermenter so i go the extra mile to decrease it

 

[mongoose33]

I thought I read somewhere on here that the volume of air that gets sucked back is a lot more than the volume of the mason jars.

I did the math on it, and as I recall, the amount of headspace shrinkage, assuming 1.5 gallons of headspace, was something on the order of .44 quarts. I have seen it suck back almost an entire quart, though.

My problem with this is I can't get it to work all the time. There appears to be a slight leak in the lid gasket or some other place such that the slight pressure to pull back the sanitizer into the first jar is just enough to be made up by the leak.

 

[murphyslaw]

I did the math on it, and as I recall, the amount of headspace shrinkage, assuming 1.5 gallons of headspace, was something on the order of .44 quarts. I have seen it suck back almost an entire quart, though.

My problem with this is I can't get it to work all the time. There appears to be a slight leak in the lid gasket or some other place such that the slight pressure to pull back the sanitizer into the first jar is just enough to be made up by the leak.

My understanding is that headspace shrinkage is only half the equation because the colder beer absorbs more CO2. One post I read said half a gallon in total. (https://www.homebrewtalk.com/forum/...he-risk-with-hoppy-beers.580706/#post-7539186) Daytripper described "multiple ballons" (https://www.homebrewtalk.com/forum/...he-risk-with-hoppy-beers.580706/#post-7539186).

I dont know the physics, I just repeat what others say!

 

[MHBT]

Well, after trying this contraption with the jars i came to the conclusion that its does not allow any liquid to be sucked back but air still gets in the fermenter so i might have me some oxidized beer as a result...the balloon might be the best option or lowering temps alot slower

 

[JONNYROTTEN]

Ditch the carboy and get a bucket and never worry about a blow off...Sometimes contraptions are just contraptions...good experiment though

 

[MHBT]

Ditch the carboy and get a bucket and never worry about a blow off...Sometimes contraptions are just contraptions...good experiment though

My main goal with this contraption was to prevent o2 from getting in the fermenter during cold crashing, not worried about a blow off, either way it failed at keeping o2 out of the fermenter

 

[shoengine]

I wonder if a cold crash from pitching temps on a 5gal batch could suck the sanitizer vertically through 7 feet of 5/8 id hose?

 

[day_trippr]

If everything is tightly connected, I'm gonna go with "Yes"...

Cheers!

 

[brewbama]

Well, after trying this contraption with the jars i came to the conclusion that its does not allow any liquid to be sucked back but air still gets in the fermenter so i might have me some oxidized beer as a result...the balloon might be the best option or lowering temps alot slower

What makes you think O2 got into the fermenter using this “contraption”?

 

[MHBT]

"What makes you think O2 got into the fermenter using this “contraption”?"

All the liquid got pulled out of A, filled up B, pushed over to C pretty much filling it, leaving A and B dry but continued pulling air in bubbling up in jar C and finally into the headspace of the fermenter

 

[shoengine]

If everything is tightly connected, I'm gonna go with "Yes"...

Cheers!

I should test that out once I get my cooling setup running. Would be a really easy experiment.

 

[brewbama]

All the liquid got pulled out of A, filled up B, pushed over to C pretty much filling it, leaving A and B dry but continued pulling air in bubbling up in jar C and finally into the headspace of the fermenter

That’s some serious suck back

 

[MHBT]

That’s some serious suck back

yeah, one good thing about this jar setup is it does not allow any liquid to get pulled into the fermenter, if i did not have these jars i would have pulled a half gallon of star san into the fermenter haha