On refrigeration...

[JJack887]

I've come across multiple threads where they say to refrigerate carbed bottles for a few days before serving. Is this a "rule"? Why would this be?

 

[SanPancho]

pressure is directly proportional to temperature for a set amount/volume of gas. so the co2 in the bottle is at higher pressure when warm than when cold. thats why warm beers will often "explode" with foam.

yeast work better in warm temps. so you let them carb up warm. they work faster.

but gasses (i.e. co2) dissolve into liquid more easily at cold temperatures. so when you chill the beer, the co2 dissolves from the bottle head space into the beer, carbonating it more than if it were warm. and at the same time, it lowers the pressure of the remaining co2 in the headspace of the bottle, because the amount of gas has decreased as it dissolved into beer. less gas, less pressure in headspace. plus less pressure from colder temps.

basically its so you get the co2 into the beer and dont have an exploding beer.

 

[JJack887]

But for a few days? I've just been chilling for a few hours.

 

[Jim311]

I've taken warm bottles right off the shelf and put them in an ice bath for 3 or 4 minutes before drinking them without any explosions or problems. I don't think you really *have* to do it if you don't want. You could probably drink it warm if you wanted..

 

[kombat]

It's a myth.

"A few days" is totally unnecessary. Think about it - when you buy a 6-pack from the store, you don't have to refrigerate them for "a few days" for the CO2 in the neck to "go back into solution." You just have to get the bottles cold, right? And there's plenty of carbonation, right?

Exact same thing with bottle-carbonated beers. CO2 is CO2. It doesn't matter if it was added artificially during bottling, or produced naturally by yeast in the bottle. It's the volumes that matter.

Just get the bottles cold, it's fine. The idea of refrigerating them for "a few days" to allow for the CO2 to "go back into solution" is a persistent old wives tale.

 

[Jwin]

"A few days" is needed to drop the sediment for a clearer pour.
Not carb related at all.

 

[HopHeavy]

I think a couple of days doesn't hurt, especially if you have to chill 4 cases stacked in the fridge. The volume of beer impacts how long you ought to wait it out. A six pack might be fine in the cooler after 15-20 minutes. On the other hand, my fridge compressor takes its time getting 10 gallons chilled to serving temps. I would say a minimum of 48 hours for that mass to get carbed right.

 

[SanPancho]

It's a myth.

Just get the bottles cold, it's fine. The idea of refrigerating them for "a few days" to allow for the CO2 to "go back into solution" is a persistent old wives tale.

if you dont believe, try it yourself. take two cans of beer, let one sit at room temp or warmer, and get the other super cold. the cold one makes a tiny "pfft" sound, maybe a little wisp of cold co2 rises up. crack the hot one- you'll likely have foam/spray on your hand.

now how long you should leave them is a different issue- you'd need to calculate interface surface area, temperature, pressure, etc. its been alot of years, but i know we did a few of these problems in physics. and thats well beyond the scope of what anybody is likely going to do for a 12oz bottle of homebrew. but the point is that you can.

because science.

 

[kombat]

if you dont believe, try it yourself. take two cans of beer, let one sit at room temp or warmer, and get the other super cold. the cold one makes a tiny "pfft" sound, maybe a little wisp of cold co2 rises up. crack the hot one- you'll likely have foam/spray on your hand.

Of course. But that's not what I was addressing. I was addressing the myth that bottle-conditioned homebrews must be refrigerated for several days, so the CO2 can "go back into solution," yet commercially-produced bottles of beer seem to be just fine after just a couple of hours of refrigeration.

There's nothing magical about the commercially produced bottles that allow them to somehow remain more carbonated at room temperature, or hold more CO2 in solution than homebrew. It's just a myth. You only have to refrigerate a bottle of homebrew for however long it takes for it to get cold, just like commercial beer. This "2 days" notion has no basis in science.

 

[SanPancho]

Ah, got it. i misunderstood you.

yes, i agree. even warm beer still has carbonation, it just wants to release it fast and hard. i've always kegged so i no nothing about bottle conditioning, but i agree, more than 24 hours seems excessive.

but i guess that also brings up the earlier post- keeping it cold for a few days will also help your bottling yeast to drop and sediment out. i hate drinking someone's homebrew and getting a yeasty pour....

 

[55x11]

pressure is directly proportional to temperature for a set amount/volume of gas. so the co2 in the bottle is at higher pressure when warm than when cold. thats why warm beers will often "explode" with foam.

yeast work better in warm temps. so you let them carb up warm. they work faster.

but gasses (i.e. co2) dissolve into liquid more easily at cold temperatures. so when you chill the beer, the co2 dissolves from the bottle head space into the beer, carbonating it more than if it were warm. and at the same time, it lowers the pressure of the remaining co2 in the headspace of the bottle, because the amount of gas has decreased as it dissolved into beer. less gas, less pressure in headspace. plus less pressure from colder temps.

basically its so you get the co2 into the beer and dont have an exploding beer.

The general analysis is correct, but the pressure is "directly proportional to temperature" only for fixed volume gas. like in CO2 tank.

But in beer bottle, the CO2 from the headspace will go into the solution because for a given CO2 volume the equilibrium external pressure drops dramatically as the temperature decreases. So if you have say 2.5 volumes of CO2 in the beer liquid - at 32F that's like 8 psi, and at 47F it's 16 psi and at 65F it's 28 psi. Which is also why it requires very low pressure to force-carb the beer to proper pressure when the beer is cold as opposed to when it's warm.

For a gas that is not soluble in water, like Nitrogen or Argon, the difference would be a very modest increase (assuming headspace doesn't shrink too much), say from 8.0 psi at 32F (273K) to 8.8 psi (306K) - since it's about 10% change in absolute temperature.

But the reason people say to put the bottle in the fridge is because cold beer tastes better. Keeping it longer than an hour or so is to help settle yeast sediment, that's all.