Cold crashing question

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bencdeck

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I am planning on building a fermentation chamber with temperature control provided by a mini fridge mated to the side of the chamber. This is my first foray into temperature-controlled fermentation. I am not sure how quickly this setup will allow me to cold crash, however. If the temperature drops over the course of a couple of days, is that fast enough?

My first beer in this setup will be a hefeweisen, followed by an ESB.

I could probably use cold packs on the carbouy to speed cooling, or I could place the carbouy in an ice bath. I also could use a wort pump and tubing to pump the wart through an ice bath and back into the carbouy to chill it very quickly. Pumping might increase oxidation risk, though.

I would welcome any suggestions or advice.
 
fwiw, I use a pair of top-freezer fridges for chambers, doing 10 gallon batches. It takes almost 48 hours to drop 10 gallons of beer from 67~68°F D-rest down to 36°F, which is fine by me.

Some folks feel it should take a lot more time - like a week or more - to crash a brew. "Ain't nobody got time for dat" 😁

Cheers!
 
Wow! I would never have thought "crashing" could be a weeklong process! I had images of frantic brewers trying to rapidly chill the beer while a stern man with a handlebar mustache and wearing lederhosen yells "Schnell! Schnell!"
 
We all develop ways to meet our goals. IMO what ever means you use is fine as long as the end result is satisfactory to your intention. With that said, I have been home brewing over 30 yrs and have employed various means to cool wort and cold crash finished beers. I have used a commercial walk in cooler to cold crash and serve successfully. But currently to cold crash I use my kegerator. Fortunately it is a huge commercial kegerator that keeps the contents at my set temperature well. Typically I give a Sixtel (5 gal Sanke keg) two days to cold crash prior to force carbonation.

IMG_20240606_202041548.jpg

I too use a refrigerator as a fermentation chamber. It is easy to control the temperature via an Inkbird temperature controller. I can fit a Spike CF5 or Fermzilla fermenter inside and it does a very good job.

IMG_20240128_194037413.jpg

Additionally when fermenting lagers I have adapted a simple process of using a cooling coil inside the fermenter with cold water pumped from a bucket of cold water kept inside a single keg kegerator that no longer is used to serve beer.

IMG_20240726_181009709.jpg

Bottom line do what ever is necessary to achieve you desired outcome. In the past I have used a 30 gal vessel with ice water to ferment, cold crash and serve from.

That is a CF5 wrapped up with bubble wrap and a packing quilt and a simple pool towel lying on top. An Inkbird is used here also to regulate the temperature inside the fermenter.
 
I think I will try letting the refrigerator cool the beer for my first attempt. It may be a slower cool over a few days, depending on the efficiency of the fridge. It will only be a 5.5 gallon batch, so hopefully it won’t be too terribly long. if that result does not seem to do the trick, I will think about using a cooling coil. That sounds like a better option than pumping beer out and back into the carbouy.
 
@bencdeck you should consider getting a better fermenter a high priority in you venture in homebrewing. Carboys, while they will do the job, pose safety hazards and limit your ability to transfer your brew without a ton of trub going along with it. There are several moderately priced fermenters available. A conical, plastic or stainless steel are your best options.
 
I am only doing 5 gallon or so batches, so the carbouy is working fine for me for now. Fragility is not an issue with my setup, and the fermentation chamber keeps light out. If I move up to a larger volume I'll go with a steel unit. Cheers!
 
I use a small dorm fridge as a fermentation chamber controlled with an INKBIRD. Cold crash by dropping the temp 10 degrees per day until I reach 34 degrees then let it sit for a few days. Patience my friend. Also use something to prevent suck back.
 
A freezer will crash faster than a fridge. I use a stand up freezer for my CF15. Can cold crash 17 gallons from 70F to 30F or lower in about a day if I want. I do tend to go 10 degrees at a time over about 3 days when time allows. I have the fermenter sealed during this crash to avoid sucking in air. I top up the headspace with CO2 after a few hours and then when I think of it to avoid collapsing the fermenter due to negative pressure. Safer alternative would be to run the Carb stone while cold crashing at something modest...maybe 5 psi...but usually don't bother as that requires moving my air circulation fan.
 
All of this concern about the speed of cooling is completely negated by the fact that you will draw a lot of oxygen into the carboy during that cooling (or suck a bunch of starsan in if you use a blowoff tube).

Any benefit of crashing will be overwhelmed by the negatives of oxidation. You need a source of CO2 to satisfy the vacuum created.
 
completely negated
Well...
need a source of CO2
If you have the required CO2 solution in place, the question of crash speed is live and well: what speed is good or bad, and why?

If you lack the required CO2 solution, it seems to me that any crashing speed is going to pull in air and/or airlock liquid (e. g. StarSan.

So these seem to be two mostly unrelated issues about cooling beer in a fermenter. Or maybe I'm misunderstanding Bobby's point?
 
I'm never concerned with the speed of cold crashing. But I don't cold crash in a fermenter. Once fermentation is complete I do a closed system transfer to a Sanke serving keg and place it in the back of my kegerator. I ferment under pressure so the beer is already carbonated enough to negate worry of negative pressure. After a few days I then pull a sample to test carbonation and drag that little heap of sediment that comes with that first pull. Add CO2 if needed then let it age and get happy until I'm ready to drink it.
 
My current process is a closed transfer from my fermenting bucket to my serving keg. Hook up the CO2 and put it in my kegerator. I carb at serving pressure and set the fridge to 35 or so and let it do it's thing. It usually takes about a week for the beer to carb up and be ready to serve. My hope is that I will start fermenting in a keg and if my serving fridge is not ready, add some CO2 and cold crash in my fermenting fridge until space is available and my serving keg has kicked.
 
Will the temperature drop from high 60s to 30s in a 5-gallon batch really create that much negative pressure? Especially if the cooling happens over a few days?
 
Well...

If you have the required CO2 solution in place, the question of crash speed is live and well: what speed is good or bad, and why?

If you lack the required CO2 solution, it seems to me that any crashing speed is going to pull in air and/or airlock liquid (e. g. StarSan.

So these seem to be two mostly unrelated issues about cooling beer in a fermenter. Or maybe I'm misunderstanding Bobby's point?

I'm wondering if this is one of those cases where participants in a forum are sometimes expected to stay extremely narrowly focused on only the question(s) posed by the OP without inferring other gaps in understanding?

The OP acknowledged that temp control is a new capability, that the fermenter type is "carboy" and is wondering what speed of cold crash is good to use and if their control method will be fast enough.

I am making assumptions that the OP does not have a CO2 source and/or has not considered the negative effects of cold crashing without a means of protecting the beer.

My suggestion, despite it being unsolicited, is to NOT cold crash at any speed without further consideration. I suppose it could be an academic exercise to temporarily assume the OP does have CO2 AND knew about the suck back problem;

Cooling a post fermented beer down for the purpose of speeding up flocculation is not necessarily always going to yield a "better beer". It may speed flocculation and you'll end up with less yeast and other fine material in your final package; keg or bottles, but at the added risk of diacetyl and acetaldehyde. One must be careful that fermentation byproducts are cleaned up before starting the cool down. I.e. the beer spent enough time in a yeast strain's comfort zone. In my case, the cool down always follows a heat up (search diacetyl rest).

The ideal speed of cool down seems to be relatively debatable. In the case of lagered beers, it seems keeping the yeast from getting stressed is desirable because some continued conditioning (cleaning up) will happen at those lower temps. If it's an ale that you're intending to transfer off the yeast a day or two after the cold crash, I would argue that any speed is fine.
 
Will the temperature drop from high 60s to 30s in a 5-gallon batch really create that much negative pressure? Especially if the cooling happens over a few days?
Yes. You can't escape physics and gas laws.

Edit: If it appears that a fermenter is not under a vacuum while lowering temps, no mater fast or slow, then air is sneaking in somehow. It can slip past a loose fitting rubber stopper, a slightly leaky lid seal, or bubbles can just go backwards through a water based airlock. It's like the question of whether a tree falling in a forest makes a noise if no one is there to hear it.
 
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I wasn't thinking about oxidation risk with my OP, but I'm grateful for the information. After reading some other threads, I'm going to set up a mylar balloon with a T-barb and clamp it off for the beginning of fermentation. I was planning on using a blow-off tube anyway, so it won't be hard to incorporate the balloon.

This thread is the one I'm using as a template (not the part about transferring; the part at the end talking about the balloon):

https://www.homebrewtalk.com/thread...-fermonster-to-corny-keg.664270/#post-8559421
 
I'm going to set up a mylar balloon with a T-barb and clamp it off for the beginning of fermentation. I was planning on using a blow-off tube anyway, so it won't be hard to incorporate the balloon.
If you add a one-way check valve between the balloon and the blow-off tube you don't need to clamp it and it won't suck back sanitizer even in the unlikely event that you use all of the CO2 in the balloon.
 
I wasn't thinking about oxidation risk with my OP, but I'm grateful for the information. After reading some other threads, I'm going to set up a mylar balloon with a T-barb and clamp it off for the beginning of fermentation. I was planning on using a blow-off tube anyway, so it won't be hard to incorporate the balloon.

This thread is the one I'm using as a template (not the part about transferring; the part at the end talking about the balloon):

https://www.homebrewtalk.com/thread...-fermonster-to-corny-keg.664270/#post-8559421
You didn't answer an implied question above; Do you have CO2 gear? For the most part I brew english styles with no temp control beyond my constant 68° basement so I just wait for it to settle but this does limit my style ability... I have tried some homespun counter-suckback devices but I found them awkward to deal with and I didn't have total confidence in them. If I lived in the states, I'd just buy @Bobby_M 's https://www.brewhardware.com/product_p/ccguardianv3.htm and call it a day, at least that is if I hadn't moved to kegging and had CO2 gear. I dropped glass carboys for medical/ergonomic reasons, but before I did I had taken to using that popular orange carboy cap with a CO2 in/racking cane out for O2-free transfers and it worked great...I'd spray Star San on the racking cane to 'lubricate' it and slowly lower it into the carboy so as to rack from the top down and stop before I hit the cloudy bottom, and yes; it held a few PSI pressure all the way down without leaking CO2.
If you have CO2 gear, there is an elegant DIY solution that a number of members on here use and I first saw it posted and described by @day_trippr (I'm pretty sure), involving a modified propane BBQ regulator...takes up very little space. I have the parts to build one myself and intend to do so when I resume my brewing and finally make space for a proper ferm-chamber.
Maybe someone can post the details here? (I'm having difficulty with searching for it right now :p )
:mug:
 
I have a commercial product that also does what the mylar balloon does if you wanted it to be less DIY. I hesitate to spam the group with every product I make, but it seems reasonable to mention it. I'm not going into early retirement on the massive profits on this thing.
https://www.brewhardware.com/product_p/ccguardianv3.htm

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