Cold crashing Questions

[Ian M HBT]

I've brewed a few batches before, and decided I might try cold crashing my current batch once it is done fermenting. So I read a few articles and forum posts on the topic and mostly understand the process but one thing that occasionally gets described keeps tricking me up.

I keg my beer and as such will be cold crashing in the kegerator for temp (34-36 F), but in the primary fermenter.

A few posts and articles have mentioned that it is possible to cold crash in the keg, and you can carbonate at the same time. Then just open the tap and the first few pints will be yeast cake. While I plan on using my fermenter as the vessel, this last part confused me.

My question is: why doesn't that happen normally then? I've never thought of the process I do to carbonate as cold crashing, but I've been doing the above and not even my first pint is yeast cake.

There are two possible reasons (in my mind) that I'm not getting a yeast cake from my first pull.

1. I'm generally pretty conservative with the siphon going from fermenter to keg, When the liquid hits the 1 gallon mark I tilt the fermenter and continue until it looks like there is noticeable amounts of floating yeast cake in the beer then pull out the siphon. There generally is a layer of beer on the bottom of the fermenter when I'm done siphoning.
   
2. Generally I roll/shake the keg while it is carbonating, though of course it will sit for 2+ days before I will drink from it. Obviously that will disturb the yeast and make it float around, but if letting it sit 4+ days in the keg (without disturbing) will get a 2-3 pints of yeast cake I'd expect my first pulls to have some noticeable yeast cake.

At the end of every keg there IS a very small amount of brown sludge which I've always assumed is yeast cake, but it is very minimal, just a coating on the bottom of the keg and very liquidy (compared to the bottom of the fermenter).

I'm not saying I don't get a yeast cake, I'm just saying it is never on the order of 2-3 pints of it as some posts mention you get when you cold crash in a keg.

What's going on here?

 

[Alex4mula]

To cold crash I put my carboy in the freezer at around 33F for 2-5 days depending on my schedule. This will always compact to a flat and tight yeast cake at the bottom (see pics) that allows me to extract to the last little bit of beer when I close transfer to the keg. Then I put the keg in the same freezer and force carb with a stone which takes 14-20hrs. Beer comes out clean from first pour and if I add gelatin then even more clearer.

 

[Alex4mula]

Two examples more. This is to me the main benefit of cold crashing.

 

[RM-MN]

When I bottle there is only a trace of yeast because I leave my beer sit in the fermenter long enough for the yeast to settle there. That same would be the case with kegging. If you want to see yeast in your keg, rush to get your beer into the keg.

 

[PersonalBrewer]

I cold crash in the keg, when I put in the kegerator where I consider it to be secondary fermenting.

I now just let the keg carbonate at serving pressure. It settles down nicely about the time it is carbonated

 

[Jag75]

When I bottle there is only a trace of yeast because I leave my beer sit in the fermenter long enough for the yeast to settle there. That same would be the case with kegging. If you want to see yeast in your keg, rush to get your beer into the keg.

How long do you leave it for . I leave on the FV for 3 weeks . I dont have an issue with yeast in my beer but when I clean the keg theres a tad film on the bottom.

 

[RM-MN]

How long do you leave it for . I leave on the FV for 3 weeks . I dont have an issue with yeast in my beer but when I clean the keg theres a tad film on the bottom.

I leave the beer in the fermenter for 3 to 4 weeks. The film of yeast in your keg was from the yeast still suspended in the beer when you kegged it. That was the least flocculant yeast. It might take a long time for all the yeast to settle out, maybe 6 to 12 months.

 

[McKnuckle]

I pretty much always rack carefully to a keg after 7-10 days in primary, just as a pro brewery would do for cold conditioning. They would transfer to a tank of course, not a keg - but it's still a second vessel for that purpose. Since homebrewers often use kegs for packaging, these nicely double as a settling tank AND package in one. For bottling it's a different story.

I only do this when primary activity has ceased and the bulk of the beer is mostly clear. If the beer is murky, obviously it shouldn't be racked, and other techniques can be employed first (time, cold).

I use either a traditional dip tube or a top-draw tube in my kegs, depending on the type of yeast used and its flocculation habits. After two weeks in the cold hooked up to gas, I've got clear, carbonated, and mostly conditioned beer.

 

[Jag75]

Does it have to be a certain temp to cause suck back while cold crashing? Have a gallon of mead with the airlock at the same level of starsan as when I put it in . It's a glass container. Its 35f and hasnt sucked back at all .

 

[TurnipGreen]

I just started kegging so I don’t have a ton of experience cold crashing in the keg. I only get one or two pours of yeasty beer on my kegs. And I say pours because most of my beer glasses are stubby 8 o 10 oz mugs.

I have noticed that most of my beers get brilliantly clear after a week or so in the keg and at least a few pours. So I bet there’s more yeast in those first several beer than I even notice. So if you’re doing the roll and shake method, I bet the yeast is more suspended then it seams.

I still do cold crashes in the primary for dry hopped beer, but I recently did a rush job for the holiday that left me with a pile of hops stuck in the poppet, so i’m gonna start trying dry hopping in a keg too.

 

[Dgallo]

Does it have to be a certain temp to cause suck back while cold crashing? Have a gallon of mead with the airlock at the same level of starsan as when I put it in . It's a glass container. Its 35f and hasnt sucked back at all .

It’s physics, specifically gas laws, it had to sucked air back in, may just not have pulled your starsan in with it

 

[mongoose33]

The 2-3 pints are how many it takes to suck up the yeast/trub that's around the dip tube; it's not like there's a ton in there, just enough to cloud the first 2 or 3 pulls from the keg.

You *can* crash in the keg, as is obvious from those above; crash in the fermenter and there should be less yeast suspended in the beer when you rack to keg, and thus, less to pull out in those first 2 or 3 pints.

Everything else being equal, I would rather have less yeast in the keg than more, but I'm not sure how large a difference that really makes. When I clean kegs there is always a film painted on the bottom of the keg, even when I've crashed in the fermenter and racked the cold beer from there to the keg.

 

[Jag75]

It’s physics, specifically gas laws, it had to sucked air back in, may just not have pulled your starsan in with it

So your saying it could suck o2 through the starsan into the fermenter, just like co2 escapes through the airlock ......gosh dang it .....its like a light switch just turned on . Well we used sorbate and sulfite so Hopefully it helps

 

[Dgallo]

So your saying it could suck o2 through the starsan into the fermenter, just like co2 escapes through the airlock ......gosh dang it .....its like a light switch just turned on . Well we used sorbate and sulfite so Hopefully it helps

Yeah. Your risk of infection will be low. I’m not overly familiar with fermenting mead but honey is fairly stable in air so idk if oxidation is an great of an issue

 

[Jag75]

Yeah. Your risk of infection will be low. I’m not overly familiar with fermenting mead but honey is fairly stable in air so idk if oxidation is an great of an issue

My son n law has wanted to do mead for ever so I took him to a class at our LHBS . There was like 16 people and we had a good time . Everyone got to make their own . This one is his so it's ok lol . Mine is still fermenting because I didnt feed it .

 

[CascadesBrewer]

I found the biggest benefit from cold crashing is to drop hops out of a dry hopped beer. I often don't mess with cold crashing something like a porter/stout/amber/etc (I don't brew pale lagers). As long as you are careful with the transfer, and most of the yeast has dropped out of the beer, I usually don't get more than maybe 6 oz of yeasty beer.

I use a mylar balloon to prevent suck back, and do closed transfers with a setup inspired by LitteRiver's post here: https://www.homebrewtalk.com/forum/threads/prevent-oxygen-during-cold-crash.662552/#post-8527464