Author Topic: Suck back during crash  (Read 296 times)

Offline Surfer801

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Suck back during crash
« on: September 19, 2022, 08:32:28 am »
Hello all,

Brand new to home brewing and loving it so far. I have a quick question on cold crashing and get some perspectives. I have seen a few "solutions" to prevent suck back during crashing but frankly they all seem pretty high maintenance so I was considering solutions.

My plan is to just insert the hose from my CO2 into my blowoff tube while it remains submerged (my blowoff is 5/8" silicon running into a 5 gal. bucket of Star San) and just barely leak the CO2 into the hose as the fermenter cools. Is there any reason this wouldn't work? And if so, why is it not used? Or maybe it is and I just haven't heard of it.

-Ryan

Offline Richard

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Re: Suck back during crash
« Reply #1 on: September 19, 2022, 08:43:44 am »
That might work, depending on your equipment and layout. My CO2 tank is nowhere near my fermenter so I wouldn't consider this. Also, many pressure regulators aren't very stable at low pressures and many fermenters can't take much in the way of positive pressure. If your fermenter can take it and your regulator can keep the pressure stable and very low then this could work. I have a tee in my blowoff line that goes to a mylar balloon on one side and through a keg being purged to a blowoff jar on the other side. When I start to cold crash I just disconnect the input to the keg and let the balloon take care of the suckback. Once set up this is very low maintenance and self-contained.
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Offline Surfer801

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Re: Suck back during crash
« Reply #2 on: September 19, 2022, 09:00:15 am »
Okay, that setup seems to make good sense. Don't think I understood the tee intersection and wasn't understanding where the balloon went. I assume you just rubber band the balloon to the joint?

Offline denny

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Re: Suck back during crash
« Reply #3 on: September 19, 2022, 09:02:59 am »
I realize it isn't a popular solution, and it depends on your equipment, but I just seal the fermenter.
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Offline ynotbrusum

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Re: Suck back during crash
« Reply #4 on: September 19, 2022, 09:11:52 am »
I pressure ferment and put a CO2 line on the in post when I cold crash.  After a day or so, i transfer under pressure to a keg with a spunding valve attached and pressure set at a couple psi less than the fermenter.  But having said that, if you have a tank that can hold pressure, you can get away with removing a blow off tube at the tail end of fermentation to build some carbonation just before crashing,,,
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Offline Megary

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Re: Suck back during crash
« Reply #5 on: September 19, 2022, 09:54:34 am »
I transfer my beer from fermenter to keg then put it in the frig for a week while it's carbonating.  Cold crash!   :)

It helps to have a way to dispense out of the keg from the top down.

Offline BrewBama

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Re: Suck back during crash
« Reply #6 on: September 19, 2022, 10:04:29 am »
I transfer my beer from fermenter to keg then put it in the frig for a week while it's carbonating.  Cold crash!   :)

It helps to have a way to dispense out of the keg from the top down.
+1. Cold crash under CO2 pressure.


*Disclaimer*: Any comment I add is simply the way I brew beer. There are certainly other ways that can be equally effective which other brewers may contribute. This is what I’ve found that works for me using my equipment and processes so I offer this for your consideration. YMMV

Offline kramerog

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Re: Suck back during crash
« Reply #7 on: September 19, 2022, 02:50:53 pm »
That might work, depending on your equipment and layout. My CO2 tank is nowhere near my fermenter so I wouldn't consider this. Also, many pressure regulators aren't very stable at low pressures and many fermenters can't take much in the way of positive pressure. If your fermenter can take it and your regulator can keep the pressure stable and very low then this could work. I have a tee in my blowoff line that goes to a mylar balloon on one side and through a keg being purged to a blowoff jar on the other side. When I start to cold crash I just disconnect the input to the keg and let the balloon take care of the suckback. Once set up this is very low maintenance and self-contained.
I agree with Richard that it is hard to get this right, not too much,  not too little.

For my plastic bucket fermenters, I have 2 holes in the lid - 1 for the fermentation lock and 1 for the mylar balloon, which is used from the get go.

Offline ynotbrusum

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Re: Suck back during crash
« Reply #8 on: September 20, 2022, 05:52:49 am »
I transfer my beer from fermenter to keg then put it in the frig for a week while it's carbonating.  Cold crash!   :)

It helps to have a way to dispense out of the keg from the top down.
+1. Cold crash under CO2 pressure.


*Disclaimer*: Any comment I add is simply the way I brew beer. There are certainly other ways that can be equally effective which other brewers may contribute. This is what I’ve found that works for me using my equipment and processes so I offer this for your consideration. YMMV

I use my clear draught system (floating diptube product) exclusively in the fermenter, so I cold crash the fermenter.  The dispensing keg needs no floating dip tube set up this way and has the thinnest of sediment of all ways I have found. YMMV and whatever works for you - go for it.
Hodge Garage Brewing: "Brew with a glad heart!"

Offline lupulus

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Re: Suck back during crash
« Reply #9 on: September 20, 2022, 07:04:22 am »
If you have one...
Sealing a Speidel 24-48h before crashing, letting it inflate a bit, works perfectly.

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