Cold crash and oxidation

[RPh_Guy]

Hello! I have another question, if the airlock does not perfectly hold the pressure, and has some vents at the base, on the first / second day of fermentation, is there a risk of oxidation? I noticed it late and only changed the airlock now

Actively fermenting yeast protect beer from oxygen pretty well, so that shouldn't be a problem.

 

[marchio-93]

Actively fermenting yeast protect beer from oxygen pretty well, so that shouldn't be a problem.

Thanks!

 

[cicquetto]

I bought the cap for my SS brewbucket. can I proceed with the cold crash without problems?

https://www.ssbrewtech.com/collections/accessories/products/1-5-tc-cap

 

[Broothru]

I bought the cap for my SS brewbucket. can I proceed with the cold crash without problems?

https://www.ssbrewtech.com/collections/accessories/products/1-5-tc-cap

NO!!!

The lid will seal the tank. Then when you chill, the volume of air will contract, creating a vacuum. The vacuum will cause stresses on the lid, sides and latches of the Brew Bucket that could cause it to implode (not explode) and collapse into itself. The Brew Bucket should not be PRESSURIZED above 2 psig (positive pressure). It should never be subjected to VACUUM (negative pressure) or it could be crushed from within. Almost any tank will hold at least some positive pressure, but nearly all tanks are susceptible to failure from very small vacuums (negative pressure).

Brooo Brother

 

[Cevan65]

NO!!!

The lid will seal the tank. Then when you chill, the volume of air will contract, creating a vacuum. The vacuum will cause stresses on the lid, sides and latches of the Brew Bucket that could cause it to implode (not explode) and collapse into itself. The Brew Bucket should not be PRESSURIZED above 2 psig (positive pressure). It should never be subjected to VACUUM (negative pressure) or it could be crushed from within. Almost any tank will hold at least some positive pressure, but nearly all tanks are susceptible to failure from very small vacuums (negative pressure).

Brooo Brother

I brew in 4 gal Anvil fermenters. I simply plug the hole in the lid and cold crash for two days. Have done this at least 20 times with two different fermenters and no issues.

 

[Broothru]

One of several possibilities:

1). You have a large liquid volume and little or no headspace; or,

2). You have an air leak around the 'plug' that allows the negative vacuum pressure to equalize; or,

3). The temperature delta between your beer's starting temperature and the crashed temperature is not that great to create a significant negative pressure vacuum; or,

4). You have an undiscovered breach of your Anvil's lid seal gasket that allows the tank to equalize; or,

5). The smaller size of a 4 gallon bucket affords greater rigidity, thus resistance to deformation, than a 7 or 14 gallon Brew Bucket; or,

6). Good luck and fortune have gotten you this far without destroying your gear. Consider it borrowed time; or,

7). One or more of the above


There's one other possible explanation, but you'd have to exist in an alternative reality where the physical laws of the universe don't.

Somewhere in my archives of aviation blunders I have pictures of a 6,000 gallon fuel truck that imploded while defueling an airplane when the truck's negative pressure relief valve wasn't opened by the refueler. In another instance the wing of a B-52 was sucked in, crushed and broke away from the fuselage, totally destroying the airplane, when the automatic wing tank vent failed to open when it was being defueled. So, scratch one steel tanker truck and one multi-million dollar bomber due to separate accidents caused by negative pressure (vacuum). I can guarantee you that both the truck and the B-52 were a lot more sturdy than your Anvils are.

Brooo Brother

 

[Cevan65]

My 4 gallon fermenter has 3 gallons of beer and 1 gallon of headspace. When I pull the plug, it is obvious that air is rushing in, so I don’t think there is any air leakage.

The temp during cold crash goes from 68 to 38 degrees. Assuming the headspace is at 14.7 psi just prior to cold crashing, my calculations show the psi of the headspace going down to 13.6 psi. I am using .0584 liters as the amount of reduction of beer volume and thus the increase in headspace volume.

So is a less than 1 psi reduction in the headspace pressure enough to damage my fermenter? I don’t think so. The first thing that would happen is the plug would get sucked into the fermenter as it is rubber.

 

[InvertedPilot]

Ebay can be your best friend. I am crashing 100 gallons in a custom fermentor. This particular blanketing regulator is capable of 7-10 WC (Water closet) which is 0.25 to 0.36 PSI. Any overpressure is vented. During crash there is no chance of blow off. Unfortunately I started cold crash with the vent line in a beaker with star san . It sucked it about 2 cups light star san solution but at least it was not oxygen. 2 cups of diluted star san are probably going to have minimal impact on taste of 100 gallons. The total amount of star san was less than a 1/4 oz in the 2 cups that were sucked back.

 

[InvertedPilot]

An alternative is the $14.00 PLAATO suck back protector. You can blow some CO2 into a mylar balloon and attach to the inlet of the suckback protector that way any suck back will be only CO2. Below is the Plaato suckback protector. It just goes inline with the fermenter bung and existing airlock. Attach a mylar balloon with co2 to the side with a rubber band and your done. Total cost under $20.

 

[day_trippr]

That's twice what I paid for my BBQ regulator...