How do you cold crash?

Just built fermentation chamber with a chest freezer and STC 1000. I have noticed that most people who have temperature control cold crash to improve the brightness of their beers. I understand the basic idea is you want to hold it around 33-34F for 24-48 hours and then rack after that. Any tips or tricks I should know? How do you guys deal with suck back? Right now I'm running a 1/2" blow off tube through a 3 piece into a 1L beaker filled with starsan - would like to avoid getting that in my beer

 

The blow off setup will almost certainly lead to suck back. You could use a 1 pc. "S" airlock, or if it's a narrow necked carboy, just cover it with sanitized foil.

I did read in the "Yeast" book about not cooling too rapidly to avoid the yeast expressing esters, but not sure if that's really that important.

 

My probe is on the outside of the carboy. When it's time to crash, I take off the airlock, place sanitized foil and set it to 0.0C. I add gelatin the next day. Keg a day or two later.

Crash cooled and ready to keg.

 

Bungee cords. Of course. My painter's tape method is unredeemingly annoying for removal/reapplication of the probe.

Back to it. I concur with the sanitized foil covering. You can't spell "suck back" without "suck"

 

I "cold crash" by dumping every frozen water bottle I have into my tub and hoping it gets cold enough to make a difference.

 

Instead of foil, I add some sanitized saran wrap over the mouth of the carboy and then secure the airlock back in and set to 35F for a few days then rack.

 

I just put my fermenter from my basement into my garage fridge for 3-4 days. I'll throw on an s type airlock if I think about it but I've never had issues with sick back keeping the 3 piece airlock in place.

 

Are all of you guys kegging? Is there still enough yeast for bottle conditioning if you cold crash and then hit the beer with gelatin?

 

I only bottle and yes there is plenty of yeast still in suspension. I have more haze from dry hopping right in primary than anything else. I also carb at 2.4vol co2 about 4.5oz corn sugar and it gets me right where I like my carb levels in about 1 week conditioning in my main floor closets at about 70 deg.

 

Of course, all this concern goes away if you succumb to kegging. Just rack to keg and chill.

 

I'd love to keg but it was already a stretch convincing SWMBO to stick a chest freezer in our kitchen for fermenting beer :cross:

 

Does the foil or plastic wrap somehow strain infectious bacteria from the nasty air that is sucked back into the fermenter? It seems it is there just to stop the bacteria that are free-falling from the sky.

My fermentation chamber just isn't fit for suck back of any kind. Probably yours are cleaner.

 

The idea with the foil is that you won't get any suckback at all. Some people are concerned about the oxygen exposure that might happen during cold crashing.

 

Ahhh...hermetically sealed. But nature abhors a vacuum, you know.

 

I use an ultra-sophisticated anti-suckback device, the design of which was stolen from a brewery that we shall not name, but they brew the hard way.

It's a gallon zip-lock baggie, some 3/8 tubing and a drilled stopper. Cut the corner of the ziplock baggie so that the 3/8 tubing fits through tightly. You want it to stretch the plastic a bit. Wrap this connection in a bit of electrical tape, to make sure that it's sealed well. Stuff the other end of the tubing into the drilled stopper.

When it's time to cold crash, I fill the baggie with CO2. I swap out the blowoff tube for the baggie/stopper combo, then move the fermenter into my cold-crashing fridge. The baggie needs to be inflated all the way, it'll pull in almost all of it when the fermenter gets down near freezing.

 

I slowly add frozen water bottles to the water in my rope-handled tub over the course of a couple days, then, once the temp drops to around 45F, I throw a bunch of them in and get the temps to drop below 40F. I then keep at +/- 2F by adding bottles every 12 hours. I wrap a North Face sleeping bag around it to help maintain temp, since ambient in my basement runs from 58F-63F. I fined with gelatin for the first time in my last batch, and it worked really well by sticking with this method.

I don't quite understand how the foil doesn't get sucked in as the pressure inside the carboy drops along with the temperature. I just recently picked up a Speidel 30L, and I can button it up with the attachments that come with it, but I was slightly concerned that it might buckle, even though it's made of really sturdy HDPE. I just filled the airlock with vodka this time, but would definitely go with the buttoning-up method if it would work well.

 

The foil is not airtight. Just acts as a barrier to any debris. If I leave the airlock on it sucks back the entire contents defeating the purpose if an airlock. @daytrippr has a good post on cold crashing with a bit if positive CO2 pressure and a ballon to acceot any excess pressure. A safety valve if you will.

My method does not prevent air entering the carboy.

 

Copy.

The massive Speidel airlock seems to have eliminated suck back, but even if some of the 100-proof vodka made it in there, I'm not at all worried by it. I'd like to eliminate oxygen intake as much as I can, but if I'm going to fine, then air will rush in anyways once I crack the seal to pour in the gelatin.

 

My ferm chamber actually just had it's cold crash maiden voyage and I'd say it was successful, so far. The beer looks really clear in the bottle, but since it's only been almost a week bottle conditioning, I haven't cracked one yet to see how clear it really is.

I'd say get an "S"-type airlock. That type of airlock allows air to flow in without having to worry about the liquid going in with it. That's what I did and I had no suck back whatsoever.

 

A bit difficult when you're in a 1 bedroom apartment

I'm going to try the foil method when I cold crash, although the bag + CO2 looks like an awesome idea (wish I had a keg setup so I can have CO2 on demand) My beer actually clears up great without cold crashing after 2 weeks in the bottle and 1 week in the fridge. Still, always fun to expand my arsenal of brewing techniques

 

For those of you who are kegging, do you cold crash before or after transfer to the serving keg? Before or after dry-hopping?

1. dry-hop --> transfer --> cold crash
2. dry-hop --> cold crash --> transfer
3. cold crash --> dry-hop --> transfer
4. cold crash --> transfer --> dry-hop
5. transfer --> dry-hop --> cold crash
6. transfer --> cold crash --> dry-hop

 

I dry hop in the keg.

Process:
Cold crash in primary -> Transfer to keg -> Dryhop in keg

 

I do something like what The_Bishop mentioned, but instead of a bag and tube I use one of those small children's punch balloons. I inflate it with CO2 from my tank, twist the mouth of it up so it doesn't deflate when I take it off the hose, and then I attach it to a fresh airlock with nothing in it. I then swap out the airlocks and untwist the balloon. No liquid and not oxygen.

My IPAs improved noticeably when I started doing this.

The end of the balloon has no problem fitting snugly around the outside of a 3-piece airlock or to the inside of the airlock on a Speidel.

 

Thanks. I've heard that the cold crashing could pull out some of the hop oils, so I was wondering if dry-hopping after cold crashing would be better. But does dry-hopping work as well in cold temps?

I have a temp-controlled chamber like the OP, so I can do this in any order--just trying to figure out the optimum way.

 

Stc at 0.5 Celsius, probe in a white labs vial of water, sanitized foil with rubber band around the top of the carboy

 

I should add: When I dryhop in the keg, the hops are in a voile bag. Keeps all the hop particles contained.

 

I stick the carboy into my fridge and keep it there until life lets me keg it.

 

As a bottler - yes, there is plenty of yeast left for carbonating the beer after cold-crashing.

 

Some of us don't have room nor money for such set-ups. Let us have our bottles and not try to always try to make us feel bad for not kegging (not saying that is happening here).

In my head, I sometimes say to myself "Look at all the trouble and expense some people go just to carb their beer and get it in a glass. I just let time & nature take its course and enjoy the fruits of their labour." - but I don't go around saying that every time someone shows off their kegs/keezers/whathaveyou. Why?

It gets annoying having to hear it, I'd imagine.

 

Hey Gavin, can you tell me more about adding gelatin? I'm dry hopping my current 2.5 gallon batch and thought a cold crash w/ gelatin would be helpful for fining.

Have you ever used this method when bottling? If so, do you just prime and bottle at the cold crash temperature?

 

Sure thing

I cold crash in the manner I previously described and usually two days later add gelatin as follows.

1: Sanitize a beaker
2: Collect ~100ml of cold water in it directly from the refrigerator's water dispenser

Knox Gelattin and Cold water in Sanitized Beaker

3: Sprinkle 1/2 tsp on the water and allow it to bloom for ~10 minutes (I cover it with sanitized foil during this time)

Add gelatin to cold water

Bloom

4: Heat it in the microwave to ~160F in 15 second bursts with a swirl after each 15 seconds
5: the gelatin solution will now be clear

Clearing Gelatin solution

6: Remove foil covering from carboy and add gelatin without splashing. I pour the gelatin through the sanitized stainless steel turkey baster I use to collect gravity samples. Its tip sits below the surface of the wort.

I do not shake or agitate the carboy at all.

7: Two days later I rack clear beer to the keg

Racking to the keg

I don't bottle aside from filling ones directly from the keg for giving to folks and competitions etc so can't say how it impacts that. From everything I have read you should have no concerns whatsoever. There are still countless millions of yeast in suspension ready and able to feed on the priming solution and adequately carbonate the beer. Cold crashing and gelatin finings will not prevent that. May take a little longer.

Hope this helps.

 

Thanks for the writeup Gavin, just a couple of clarifying questions (no pun intended )

1.) Do you have any recommendations for heating the gelatin without a microwave? I was thinking 10 minute bloom in sanitized pint glass -> transfer to saucepan and heat to 170F -> transfer back to sanitized pint glass -> transfer to beer

2.) After you add the gelatin, do you keep the beer at cold crash temperatures?

 

170 is too high. I shoot for somewhere around 155, and would not exceed 160.

 

1)Use a a stove as you describe but don't heat that high as the gelatin will be rendered ineffective. No need to go as high as 160F. I'm usually 150-160. I should have been more clear on that.

I would pour it from the pot directly into the FV. No need for a beaker/pint glass if you are using the stove. Just heat it slowly for control and swirl it. Once it's clear it's done.

2)Yes