Let's Talk About Cold Crashing!

[GrowleyMonster]

So after almost three weeks in primary, I moved a 5 gallon batch of strong-ish all-grain that was no longer gassing, to secondary. It came back to life for a couple of days and quit working once and for all, and today I decided to put the whole fermenter (a Big Mouth Bubbler) in the fridge for a day or two before transferring to keg. I am trying to keep sediment in the keg down to absolute minimum levels. Is this a good idea, and will it do any good? Is a day or two long enough? The fridge is also my kegerator and with the BMB in there, I don't have room for a corny keg, so I don't want to keep it in there for long as I don't have much beer in bottles and I don't like bottling. I really can't go more than about 4 days with the fermenter occupying all my kegerator space.

 

[McKnuckle]

One of the conveniences of kegs is not having to be obsessive about transferring a little sediment. Cold crashing in the fermenter invites oxygen ingress since you have to remove the airlock, even temporarily. If your BMB has a spigot, just transfer now to the keg, then put the keg in the serving location and attach CO2 gas. You're done.

If you wait a week or two, any minimal sediment in the keg will settle to the bottom. When you pull the first servings, it will come out immediately and then is gone forever. It's utterly convenient.

 

[GrowleyMonster]

One of the conveniences of kegs is not having to be obsessive about transferring a little sediment. Cold crashing in the fermenter invites oxygen ingress since you have to remove the airlock, even temporarily. If your BMB has a spigot, just transfer now to the keg, then put the keg in the serving location and attach CO2 gas. You're done.

If you wait a week or two, any minimal sediment in the keg will settle to the bottom. When you pull the first servings, it will come out immediately and then is gone forever. It's utterly convenient.

Thank you for your reply that is obviously born of experience. You are right, but as I said in the OP, I have already put the BMB in the fridge and the process has begun. I considered the fact that after 4 or 5 glasses, the sediment is no longer evident. I also considered the use of a floating dip tube so that instead of the first glasses being tainted, it would be the last one or two. Neither option is really acceptable. Now that I am committed on this course, my question is not one of whether or not I should do what I have already done anyway, but how long I should continue the cold crash in the fermenter before transferring to keg.

Your reply does give me an idea, though. Or actually it makes me re-examine an idea that I quickly discarded before, instead of figuring out how to efficiently implement it. What if I cold crash in a keg, and then transfer from the crash keg to a serving keg, retaining those first four glasses or so for use as a starter or simply to add to the next batch to be cold crashed and keg conditioned?

That still doesn't tell me, though, how many days I ought to keep the current batch under refrigeration before transferring to its last and final vessel. (not counting my stomach, of course.) I am leaning toward a 48 hour crash and then moving to a purged keg, and carbonating under pressure. I am hoping that the first glass, the last glass, and every glass in between will then all be equally good.

Of course another option would be a floating dip tube, and recycling the remainder when the net weight is down to just one or two glasses worth.

And another idea just presented itself to me. What if I replaced the dip tube with another, with another either longer but with a "U" bend in the foot, or simply cut off shorter? All I am really looking for is for every glass to be of equal high quality. A couple of glasses "wasted" is no biggie since ultimately they will not be wasted. I just don't want to pull a glass, either first, or last, that has undesirable sediment in it. Not a glass offered to a guest, which would shame me, nor a glass drank myself, which would disgust me, which from past experience I know it would.

 

[CascadesBrewer]

how long I should continue the cold crash in the fermenter before transferring to keg

In my experience 2 to 3 days is fine. If your beer spent 3 weeks in primary and time in a secondary, I am not sure there would be much left in suspension that cold crashing will drop out. I tend to only cold crash dry hopped beers as it does a good job of dropping the hops to the bottom. The standard Porter/Stout type beers tend to have dropped pretty clear after 2 weeks...I brew very few beers I expect to be crystal clear though.

 

[micraftbeer]

Ditto, 2-3 days. The advantage of crashing in a clear vessel, you can see. If you notice a big moving color change front, wait until it's pretty much at the bottom, then transfer.

I recently started cold crashing in a keg. Similar thinking to what you had above. I replaced the standard dip tube with a floating one. Cold crash in that keg and don't have to worry about any oxygen coming in from vacuum. Then after the 3 day mark, transfer to my serving keg.

 

[GrowleyMonster]

Ditto, 2-3 days. The advantage of crashing in a clear vessel, you can see. If you notice a big moving color change front, wait until it's pretty much at the bottom, then transfer.

I recently started cold crashing in a keg. Similar thinking to what you had above. I replaced the standard dip tube with a floating one. Cold crash in that keg and don't have to worry about any oxygen coming in from vacuum. Then after the 3 day mark, transfer to my serving keg.

Yeah I like that. But the transfer. How do you know when to stop the transfer from the cold crashing keg to the serving keg? Put a scale under the crash keg, tared to the empty keg weight? I guess that is one way to do it. And the floating dip tube... would it be practical to cut it a bit short, so the end of the tube could never suck up the sediment? I sure wish they made clear acrylic corny kegs.

 

[day_trippr]

If the kegs are the same size, do you need to know the fill volume?

Cheers!

 

[brew703]

Get a floating dip tube. They are great.
Once my keg kicks there is very little beer left, maybe 1/4 pint if that.
As for cold crashing 2-3 days is what I do but I also use a mylar balloon with co2 to avoid oxygen exposure.
And I also do not secondary.

 

[mongoose33]

How long? Doesn't really matter unless you can ensure you transfer no sediment to the keg. It'll continue to drop clear in the keg.

It's a question of where you want that clearing to occur.

I use a Spike conical for my fermenter; I began crashing yesterday morning and normally I'd expect that either by tonite or tomorrow I'd transfer it to keg--so 36 to 60 hours. So, that's consistent with the 2-3 day suggestions above. I have a glycol chiller so I can accelerate crashing a bit, as i can take that down from the mid-60s to 38 degrees in maybe 8 hours depending on ambient. In a refrigerator, maybe 2-3 days is probably fine.

But...the beer is a Kolsch and I'm using Wyeast Kolsch yeast which is a low flocculating yeast, i.e., it'll still have yeast in suspension if i keg it too soon. So I'll probably wait more until I keg it. How much more? Maybe Tuesday. Maybe Thursday. Probably some evening when I have time to clean the fermenter right after kegging. But I'm not going to get all worked up over it. It'll still be beer, I expect it to be very good, and I can wait. Will there be a significant difference between kegging it on Monday and kegging it on Thursday? No. It'll just be clearer on Thursday--and continue to clear in the keg.

*****

Now, having said that--transferring to a secondary, unless it's a big beer and you need the fermenter for something else, is really unnecessary. Sometimes people will use a secondary for long-term aging, and maybe for adding fruit or other adjuncts, but otherwise all it does it promote oxidation of your beer.

I brewed a lot of beer using my Bigmouth Bubbler. Gave up secondaries after about my 3rd batch.


All this is...my 2 cents.

 

[McKnuckle]

At some point in your brewing journey you may eventually come to fear oxidation more than sediment. At that point, you'll eliminate as much vessel movement/transfer as possible. Sediment is temporary. Oxidation is forever.

 

[GrowleyMonster]

Get a floating dip tube. They are great.
Once my keg kicks there is very little beer left, maybe 1/4 pint if that.
As for cold crashing 2-3 days is what I do but I also use a mylar balloon with co2 to avoid oxygen exposure.
And I also do not secondary.

Like a balloon filled with CO2 in place of the airlock? So the gas in the fermenter can contract as it cools and only draw CO2 in? I like that idea.

 

[GrowleyMonster]

Okay, lots of great answers to think about. So I am thinking I need to figure out the best way to get beer from primary straight to keg, with no sediment. As in zero or as close as possible. So here is what I am thinking for the NEXT batch.

1. No more pouring fresh wort on top of the previous batch trub even if it is painfully convenient (as in emptying fermenter on a brew day) so the trub level doesn't go too high. This last batch had it up to the spigot. I will also add a second spigot about an inch higher than the original one so I can initially draw down from a bit higher in the fermenter. I will continue to recycle yeast, but in the form of a liquid starter. No dead yeast to take up space in the bottom of the fermenter.

2. I will cold crash right in primary by moving the BMB to the fridge for 3 days. To totally eliminate any air getting sucked in I will replace the airlock with a T and the top leg will be fitted with a balloon to serve as a CO2 reservoir. The third leg of the T will be for CO2 fill. Occasionally as needed during the first day I will top up the CO2 in the system via the T connection. Zero air should get sucked in that way.

3. After cold crashing, I will transfer beer to a CO2 purged keg, maintaining a slight positive pressure in the fermenter with CO2. Transfer will begin from the higher spigot. Transfer via lower spigot will be done slowly so as not to disturb the trub, and I will not be tipping the fermenter to get the bottoms.

4. Any beer remaining below the level of the lower spigot will be carefully drawn off into a one gallon fermenter using all precautions to keep everything in a purged and closed system, for secondary settling and storage. This small amount will be added to the next keg as space allows, or else will be bottled in brown PET bottles, and force carbed in the bottle. I already have some SS carb caps, and a 6x manifold for carbing will be here tomorrow. I am quite pleased with the few bottles I have force carbed in the bottle. Works pretty good if you leave the CO2 hooked up all day, and leave the carbo cap on instead of replacing with a standard screw cap. I tried the plastic ones but the SS ones are actually cheaper and don't suck like the plastic ones do.

So this will eliminate secondary for the lions share of the batch, and ensure complete isolation from ambient oxygenated air, while ensuring the lowest practical level of sediment in the serving keg. The bottoms will be less than a gallon and so the risk of oxygen exposure is not a dealbreaker, and the precautions I am thinking of ought to keep that risk low. The one gallon jug will fit easily into the kegerator along with the currently in use serving keg. I have a backpressure bottling rig that I can use to purge bottles with CO2 and then gravity fill.

I am going to be very busy tomorrow so I will transfer the current batch to a purged keg this evening.

 

[bkboiler]

Most times I just keg my beer straight from fermenting, the temp of the kegerator helps it drop clear. .. usually the first pint is cloudy and it's crystal clear after that..
Saves a step and risk of oxydation.. .
I'm not planning to go back to cold crashing until I get a vessel I can apply mild co2 pressure to...

 

[mongoose33]

Okay, lots of great answers to think about. So I am thinking I need to figure out the best way to get beer from primary straight to keg, with no sediment. As in zero or as close as possible. So here is what I am thinking for the NEXT batch.

1. No more pouring fresh wort on top of the previous batch trub even if it is painfully convenient (as in emptying fermenter on a brew day) so the trub level doesn't go too high. This last batch had it up to the spigot. I will also add a second spigot about an inch higher than the original one so I can initially draw down from a bit higher in the fermenter. I will continue to recycle yeast, but in the form of a liquid starter. No dead yeast to take up space in the bottom of the fermenter.

If you're going to reuse yeast, then pull it out, rinse it, and repitch it.

When I used my BMB I rigged a line from the spigot to the QD on the keg, but I'd clear the line and the spigot by running a little of the beer through that line until it ran clear. Then I'd reattach the QD, put it on the keg, open up the spigot, and in the beer went, to the keg.

But---if the keg had air in it, I was doing nothing much different than transferring to a secondary. So I got to a method of purging my kegs. I have a spare keg (though you can do this with 5-gallons of Star-San in a bucket) in which I keep 5 gallons of Star-San. I will pump that into the new keg using CO2. At the end I let CO2 bubble up from the bottom until the headspace is full of bubbles which are full of....CO2! So the keg now has Star-San in it, and CO2 bubbles. I seal it up, and use that to transfer to the next keg.

Meanwhile, the one I just emptied is full of CO2 only. There's a little residual star-san in the bottom which you can clear if you want by attaching a QD to the OUT post and the residual pressure will blow that out. I have a tube in mine so I can direct that into a sink.

At that point, I have a clear and purged keg. I attach the QD from the spigot, then another line from the IN post back up to the top of the fermenter, so that any CO2 that is displaced by the beer flowing into keg is directed back into the top of the fermenter so the beer there isn't being oxidized by air drawn in as i drain it. Closed transfer!

Here's a pic showing that. Today I use a small piece of rigid tubing in a drilled stopper, but when I first did this I cut the top off an airlock to attach the line.

 

[GrowleyMonster]

If you're going to reuse yeast, then pull it out, rinse it, and repitch it.

When I used my BMB I rigged a line from the spigot to the QD on the keg, but I'd clear the line and the spigot by running a little of the beer through that line until it ran clear. Then I'd reattach the QD, put it on the keg, open up the spigot, and in the beer went, to the keg.

But---if the keg had air in it, I was doing nothing much different than transferring to a secondary. So I got to a method of purging my kegs. I have a spare keg (though you can do this with 5-gallons of Star-San in a bucket) in which I keep 5 gallons of Star-San. I will pump that into the new keg using CO2. At the end I let CO2 bubble up from the bottom until the headspace is full of bubbles which are full of....CO2! So the keg now has Star-San in it, and CO2 bubbles. I seal it up, and use that to transfer to the next keg.

Meanwhile, the one I just emptied is full of CO2 only. There's a little residual star-san in the bottom which you can clear if you want by attaching a QD to the OUT post and the residual pressure will blow that out. I have a tube in mine so I can direct that into a sink.

At that point, I have a clear and purged keg. I attach the QD from the spigot, then another line from the IN post back up to the top of the fermenter, so that any CO2 that is displaced by the beer flowing into keg is directed back into the top of the fermenter so the beer there isn't being oxidized by air drawn in as i drain it. Closed transfer!

Here's a pic showing that. Today I use a small piece of rigid tubing in a drilled stopper, but when I first did this I cut the top off an airlock to attach the line.

View attachment 666864

For purging kegs, I do similar. The bubbles trick is a refinement I hadn't thought of, though. It must be more effective than how I have been doing it. I have also been purging the secondary, though. Just imperfectly. In place of the beer out post, I clamp a hose onto the spigot. In place of the CO2 post, I push a hose into the hole in the stopper. Of course I can't pressurize the BMB but that's the breaks.

 

[mongoose33]

For purging kegs, I do similar. The bubbles trick is a refinement I hadn't thought of, though. It must be more effective than how I have been doing it. I have also been purging the secondary, though. Just imperfectly. In place of the beer out post, I clamp a hose onto the spigot. In place of the CO2 post, I push a hose into the hole in the stopper. Of course I can't pressurize the BMB but that's the breaks.

Here's a pic showing it--one thing to note though that you want to catch it when it starts bubbling. Put too much CO2 into that OUT post and you'll get a Star-San geyser. Don't ask how I know that.

I just cleaned a bunch of kegs this afternoon, and to manage the bubbling I just connect and disconnect the QD a few times.

 

[GrowleyMonster]

Okay here goes nothing. I just received the new keg lid I was waiting on, and so I repurged the target keg and did a closed loop transfer, and topped up the pressure. I will give it a taste test tonight but I am optimistic. straight from the fermenter even the leavings tasted pretty decent. If it isn't excellent then I will give it another three days or so to condition in the keg.

I still have the 2 gallon batch from sparging the mashed grain from this batch. It is in a BMB and the large volume of gas will cause a lot of air to be sucked in if I cold crash in the fermenter, and I am not set up yet with my balloon rig for maintaining pure CO2 on top of the beer. The sediment is a VERY fine layer and it hasn't made a single bubble that I have seen in the last two days. So I think I will take that small batch straight to bottle. I don't have an empty keg, anyhow. I will be getting a 6x manifold delivered tomorrow and I will set that up with QDs and carbo caps for bottle conditioning without sugar. So I am hoping to have a sediment free bottled batch out of this, with good carbonation. Next batch I will be able to cold crash properly before bottling.

I wonder if Mrs. Monster will notice if I get another corny keg? I could hide it somewhere, maybe...

 

[mongoose33]

Conditioning of beer is a funny thing. Don't rely on just tasting it, then giving it another three days in the keg and assuming that's it.

I've had beer go from "meh" to fabulous in a few days; I've also had beer take a couple/three weeks to condition. It just....depends. So don't assume that if you aren't enthralled by beer at one point in time that you won't find it vastly improved at a later date.

 

[GrowleyMonster]

Just had a sample. Very clear, no sed at all. Mrs. Monster found it a bit bitter for her taste. Well, it is a little drier than early batches I made, when I only fermented 13 or 14 days and went straight to keg and fridge. It is not heavily hopped at all, with an ounce of Cascade boiled an hour for the 5 gallon batch. I liked it very much. I only drink a glass a day, usually, and she just sips out of mine unless it is just perfect by her taste as she is not much ofa beer drinker. So it will have plenty of time to mature before the keg is half empty, but I'm okay with drinking it now.

Thanks to all who replied. I got a lot of good ideas from your posts that should incrementally improve my beer quality.

 

[ChaosB]

One of the conveniences of kegs is not having to be obsessive about transferring a little sediment. Cold crashing in the fermenter invites oxygen ingress since you have to remove the airlock, even temporarily. If your BMB has a spigot, just transfer now to the keg, then put the keg in the serving location and attach CO2 gas. You're done.

If you wait a week or two, any minimal sediment in the keg will settle to the bottom. When you pull the first servings, it will come out immediately and then is gone forever. It's utterly convenient.

What do you do when the keg post gets clogged?

 

[brew703]

Like a balloon filled with CO2 in place of the airlock? So the gas in the fermenter can contract as it cools and only draw CO2 in? I like that idea.

Yes that is correct. It's been working great for me.

 

[Jokester]

I take a beer with a sediment layer and place it in the freezer on a bag of ice for a few hours. That freezes the sediment, then I siphon out the beer. Does that beer now still have yeast in it needing to flocculate ? Its not the clearest, its pretty good but cant see through it though.
Cool.
Srinath.

 

[McKnuckle]

What do you do when the keg post gets clogged?

This doesn't happen unless you have hop debris in the primary. I never do, so this hasn't been an issue for me in dozens of kegged batches. Yeast and break trub flow easily through poppets.