Dry hop and Cold Crash

[Sdiddy84]

I'm dry hopping a Black IPA and this is my first brew.

I want to cold crash to settle everything and clear the beer up a bit. If I cold crash for 2 days should I include those days in my dry hop? I dry hopped in primary and I'm gonna keg.

 

[GPP33]

If you're kegging cold crashing is dangerous and unecessary. When you cold crash you'll get a ton of suck back. When you cool the liquid it shrinks and gasses go into solution. Best case you'll suck a bunch it air in, worst case you'll suck in whatever is in your air lock.

Just keg it, hook up the CO2 and chill it. Your first pint will be cloudy but it'll clear up quickly.

 

[Sdiddy84]

Ok so let it sit in primary for the 7 days then rack to the keg?

 

[GPP33]

I do 14 days then keg. 7 is really quick and probably not enough time for the yeast to settle out and clean up.

 

[Sdiddy84]

I ment 7 days for dry hop. It's already been in primary for 10.

 

[samall415]

I cold-crash my beers before kegging. I want to avoid the hops in my keg, as I've had issues in the past with the hops clogging my keg line. To avoid suck-back (the airlock liquid getting into the beer), I place my carboy in the fridge, remove the airlock, and cover the opening with foil + a rubber band. After a few hours, when the beer reaches the fridge temperature, I put the airlock back on.

I don't think cold crashing for 2 days is necessary. I just cold crash overnight and keg the next day. When I keg, I use a muslin bag over the autosiphon and take care not to siphon the sediment at the bottom. My beers have ended up relatively clear.

To answer your question, I don't count the cold-crash time as part of the dry-hop time. If I wanted to dry hop for 7 days, I would cold-crash day 7 and keg day 8. But at this point, an additional day isn't going to make or break your beer.

 

[max384]

I'm dry hopping a Black IPA and this is my first brew.

I want to cold crash to settle everything and clear the beer up a bit. If I cold crash for 2 days should I include those days in my dry hop? I dry hopped in primary and I'm gonna keg.

Personally, I cold crash after dry hopping. In other words, if I ferment for 14 days, I'll then dry hop for 7 days (or whatever time frame I choose), then cold crash. If I'm using a bag for my hops, I remove the hops for cold crash. If I just add them straight to the beer, I will transfer to a secondary for cold crash.

Long answer short, no, I don't include cold crash days into dry hop days.

 

[max384]

If you're kegging cold crashing is dangerous and unecessary. When you cold crash you'll get a ton of suck back. When you cool the liquid it shrinks and gasses go into solution. Best case you'll suck a bunch it air in, worst case you'll suck in whatever is in your air lock.

Just keg it, hook up the CO2 and chill it. Your first pint will be cloudy but it'll clear up quickly.

I think this post is a bit of fear-mongering. Cold crashing is very commonly used, and without all of these ill effects. The only way you'll suck in the liquid in your air lock is if it is over filled.

As far as sucking air in is concerned, let's look at some math.

The coefficient of thermal expansion for water is 0.00021 per degree C. On average, you're probably dropping about 15 degrees C when going from fermenting temp to cold crash temp. This means that the expansion multiplier will be 1.0032. So, if we are talking a 6 gallon pre-keg/bottle volume, that will be a decrease of 0.019 gallons of volume, which is less than a third of a cup of air, which is comprised of only 21% oxygen anyhow, so you're only allowing roughly 1 tablespoon of oxygen in. Keep in mind that water actually expands from 7 C to 0 C (and during freezing too, of course), so if your cold crash temp is below 7 C, which most are, the amount of liquid compression will actually be less than I had calculated.

If you're cold crashing in a carboy, you probably have minimal headspace, so the air compressing would be negligible. Worst case you have a couple of gallons of air in a bucket. In this case, the coefficient of thermal expansion for air is 0.0034. Given the 15 degree C temp drop, that would give a multiplier of 1.05, which would be about a cup and half of air, which would be about five tablespoons of oxygen.

So, you have a suck back of anywhere between less than one and five tablespoons of oxygen when cold-crashing. Keep in mind that CO2 is heavier than oxygen and the blanket of CO2 will mostly stay next to beer. Also keep in mind that we only cold crash for a day or two usually, and also keep in mind that if we keg, we can also blanket the headspace with CO2 before transferring to keg (at least I always do).

Bottom line is that the worry about oxidizing beer or sucking in liquids from the air lock during cold crashing is way overstated and overly worried about.

I'll take the minute chance of a tiny bit of oxidation as a trade-off for clearer beer every single time.

 

[JONNYROTTEN]

If you're kegging cold crashing is dangerous and unecessary. When you cold crash you'll get a ton of suck back. When you cool the liquid it shrinks and gasses go into solution. Best case you'll suck a bunch it air in, worst case you'll suck in whatever is in your air lock.

Just keg it, hook up the CO2 and chill it. Your first pint will be cloudy but it'll clear up quickly.

I disagree. I've lost a half a keg twice not cold crashing after joining the oxidation paranoia craze. The yeast and hops will eventually settle out without crashing but then you could miss the freshness waiting for it to clear. I'm back to crashing after dry hopping

 

[Sdiddy84]

I think this post is a bit of fear-mongering. Cold crashing is very commonly used, and without all of these ill effects. The only way you'll suck in the liquid in your air lock is if it is over filled.

As far as sucking air in is concerned, let's look at some math.

The coefficient of thermal expansion for water is 0.00021 per degree C. On average, you're probably dropping about 15 degrees C when going from fermenting temp to cold crash temp. This means that the expansion multiplier will be 1.0032. So, if we are talking a 6 gallon pre-keg/bottle volume, that will be a decrease of 0.019 gallons of volume, which is less than a third of a cup of air, which is comprised of only 21% oxygen anyhow, so you're only allowing roughly 1 tablespoon of oxygen in. Keep in mind that water actually expands from 7 C to 0 C (and during freezing too, of course), so if your cold crash temp is below 7 C, which most are, the amount of liquid compression will actually be less than I had calculated.

If you're cold crashing in a carboy, you probably have minimal headspace, so the air compressing would be negligible. Worst case you have a couple of gallons of air in a bucket. In this case, the coefficient of thermal expansion for air is 0.0034. Given the 15 degree C temp drop, that would give a multiplier of 1.05, which would be about a cup and half of air, which would be about five tablespoons of oxygen.

So, you have a suck back of anywhere between less than one and five tablespoons of oxygen when cold-crashing. Keep in mind that CO2 is heavier than oxygen and the blanket of CO2 will mostly stay next to beer. Also keep in mind that we only cold crash for a day or two usually, and also keep in mind that if we keg, we can also blanket the headspace with CO2 before transferring to keg (at least I always do).

Bottom line is that the worry about oxidizing beer or sucking in liquids from the air lock during cold crashing is way overstated and overly worried about.

I'll take the minute chance of a tiny bit of oxidation as a trade-off for clearer beer every single time.

I think you need to teach at Niagara College in their Brewing program. Very informative. Thanks.

 

[sky4meplease]

I find dropping the temperature down slowly for a cold crash prevents suck back.

 

[max384]

I think you need to teach at Niagara College in their Brewing program. Very informative. Thanks.

Haha. Thanks... but that was me just regurgitating some old college physics. In actuality, I needed Google to help fill in the gaps in my knowledge for this post, since it's been a few years.

Where on the rock do you live BTW?

 

[eric19312]

headspace in primary fermenter is not usually negligible. The thermal expansion of the gas in the headspace is a real issue and you will suck in atmosphere if you cold crash in primary.

I have had good luck dry hopping in primary at end of fermentation for 2-7 days and then racking to kegs. I dry hop with free floating pellet hops. I am kind of careful transfering beer into kegs but its ok if a bit of hop (small amount) comes through. I have tried pressurized transfers but not sure it is worth the extra effort. I purge the keg with CO2 and leave it on CO2 while it chills in my keezer. Once chilled I disconnect the CO2, release the pressure, open it up and fine with gelatin. 1/2 tsp in 1/2 cup warm water. Close it back up and purge again with CO2 and hook back up to pressure. If I need the beer soon I will go overnight at 20-30 PSI at this point usually just leave it at serving pressure and it is drinking good in a week.

I usually brew 10 gallons. The second keg gets a second blast of dry hop when the first keg kicks. I do 1 ounce in a metal tea bal. I disconect CO2, release the pressure, open the keg, get that tea ball in there fast, close it back up and purge again. You have to be quick cause it will foam. But that second keg is awesome when I do this.

 

[Sdiddy84]

Haha. Thanks... but that was me just regurgitating some old college physics. In actuality, I needed Google to help fill in the gaps in my knowledge for this post, since it's been a few years.

Where on the rock do you live BTW?

From Trinity Bay, Now living in Ontario, In Niagara Region.

 

[Sdiddy84]

I have had good luck dry hopping in primary at end of fermentation for 2-7 days and then racking to kegs. I dry hop with free floating pellet hops. I am kind of careful transfering beer into kegs but its ok if a bit of hop (small amount) comes through.

good to hear. I dry hopped the same way and plan on racking to my keg with a piece of sanitized cheese cloth over the end of the racking cane.

 

[GPP33]

I think this post is a bit of fear-mongering. Cold crashing is very commonly used, and without all of these ill effects. The only way you'll suck in the liquid in your air lock is if it is over filled.

As far as sucking air in is concerned, let's look at some math.

The coefficient of thermal expansion for water is 0.00021 per degree C. On average, you're probably dropping about 15 degrees C when going from fermenting temp to cold crash temp. This means that the expansion multiplier will be 1.0032. So, if we are talking a 6 gallon pre-keg/bottle volume, that will be a decrease of 0.019 gallons of volume, which is less than a third of a cup of air, which is comprised of only 21% oxygen anyhow, so you're only allowing roughly 1 tablespoon of oxygen in. Keep in mind that water actually expands from 7 C to 0 C (and during freezing too, of course), so if your cold crash temp is below 7 C, which most are, the amount of liquid compression will actually be less than I had calculated.

If you're cold crashing in a carboy, you probably have minimal headspace, so the air compressing would be negligible. Worst case you have a couple of gallons of air in a bucket. In this case, the coefficient of thermal expansion for air is 0.0034. Given the 15 degree C temp drop, that would give a multiplier of 1.05, which would be about a cup and half of air, which would be about five tablespoons of oxygen.

So, you have a suck back of anywhere between less than one and five tablespoons of oxygen when cold-crashing. Keep in mind that CO2 is heavier than oxygen and the blanket of CO2 will mostly stay next to beer. Also keep in mind that we only cold crash for a day or two usually, and also keep in mind that if we keg, we can also blanket the headspace with CO2 before transferring to keg (at least I always do).

Bottom line is that the worry about oxidizing beer or sucking in liquids from the air lock during cold crashing is way overstated and overly worried about.

I'll take the minute chance of a tiny bit of oxidation as a trade-off for clearer beer every single time.

I think you need to teach at Niagara College in their Brewing program. Very informative. Thanks.

Don't believe everything you read on the Internet.

The CO2 blanket is a falacey and you'll suck way more in than you calculated. I cold crashed a couple of times, until I sucked about a 1/3 gallon of starsan into two carboys through blow off tubes. Beer turned out ok but it really opened my eyes to how much of a vacuum is created. If you use an "s" airlock you'll just suck air. There's a time and a place for everything but a dark beer and and IPA IMO are two places where I wouldn't cold crash (let alone a black IPA). Never said it was the devil, just that it presents risks and when kegging those risks are kinda silly to take. The keg will by default allow you to cold crash without risk then flush out the stuff that falls. If you can't transfer without sucking up a bunch of nasty stuff then a cold crash my be necessary.

Oh, and oxygen isn't my only concern with air getting near my beer. There are literally thousands of different types of mold and bacteria floating around in our air. Most are totally harmless but I still don't want em near my beer. There are lots of people who get infections in their beer and can't figure out where they came from. Not saying cold crashing is to blame but atmospheric exposure may be. Go buy some pasteurized apple juice from the non-refrigaded section of your local market. You can leave it on your counter for years without any signs of infection. Take the lid off and I'd bet that in a couple weeks it's growing some nasty stuff. Maybe I'm paranoid but my beer appreciates it.

 

[samall415]

I've read several articles and threads on cold crashing, but there are several different schools of thought out there. Some want to avoid cold crashing because they don't want to risk exposing their beer to air, others say it's okay. It's been a while since I've taken physics, but here's my thought on it:

You will introduce oxygen to the beer. However, you want to keep this amount minimal. Yes, when you cool the beer, gasses are more easily absorbed into solution. I suppose the idea is that not too much oxygen is absorbed into the beer if you don't cold crash for an extended period of time. That's why I just cold crash my beer overnight.

The "shelf life" of your beer can depend on how much oxygen is introduced. It could be a month or a year. If you find that your beers are stale, you might want to consider a different cold crash method. Some people cold crash in one keg, under CO2, then rack into another keg.

All that said, I haven't experienced many issues cold crashing. But I also tend to drink my beer within a month or two after kegging. Not sure what it tastes like after that.