"Two weeks in the cool so the co2 is absorbed by the beer"

[NickW]

I understand the concept behind this, but does it work in practice?

When drinking commercial ale, God knows how long its been sitting out in ambient temperature in the supermarket. I get it home, chill for half hour and enjoy a beer with no carbonation or head issues whatsoever.

What's the science behind this? Does the co2 absorb better the instant the beer is cooled?

I'm starting to believe it has little relevance with bottled beer due to the tiny amount of headspace.

Anyone's 2 pence?

 

[dave0w]

its done with forced carbonation, so it dont matter if you drink warn or chill for a week it will be gassed ever way

 

[dave0w]

you tube search forced carbonation

 

[NickW]

Not sure that would matter... co2 is co2... whether the yeasties did it or not.. and besides, I do get shepherd neame 1968 from time to time, and that is bottle conditioned..

 

[GavH]

Comparing homebrewed with commercially produced is not like-for-like surely? :wha: Or am I missing something?

 

[coyspurs]

Have ran a few pubs in my time and the real ales in those used to have top blanket of CO2 on them from the moment they had settled, apart from keeping the beer longer, it helped with dispensing of it. So I always assumed it was as it said "a blanket covering" rather than entering and mixing with the beer.


Mike

 

[mike77]

I'm starting to believe it has little relevance

I agree. On many occasions I have taken beer from the warm cupboard and chilled it and drank it in less than an hour with no issues with carbonation.

That said if you open a bottle of Champagne which has higher carbonation levels, without chilling it, it will froth up/spray.

 

[honeymonster]

I agree. On many occasions I have taken beer from the warm cupboard and chilled it and drank it in less than an hour with no issues with carbonation.

Just because it's not cold doesn't mean it will be flat.

My understanding of forced carbonation is that it doesn't matter what temp the beer is at because the co2 has been forced into the beer under pressure. I don't think temperature has much to do with it.

With homebrewing and natural carbonation, if you can call it that, needs a warm period for the yeast to eat the priming sugar and convert it into co2, and the cold period to help the co2 dissolve into the beer.

They are two different processes that have the same end result - fizzy beer!

I'm sure I've read on here that once your homebrew is carbed properly it doesn't need to be kept cool anymore. Someone else might be able to confirm this.

Comparing homebrewed with commercially produced is not like-for-like surely? :wha: Or am I missing something?

Not unless I am too!!!

 

[NickW]

I'm sure I've read on here that once your homebrew is carbed properly it doesn't need to be kept cool anymore. Someone else might be able to confirm this.

Cheers honeymonster, I'd also like someones take on this.

 

[chrig]

could this be tested by putting half the bottle in the cool for two weeks and leaving the rest in the warm. Chill both one night and crack them open.

I'm not bottling anything for a few weeks but will try it.

 

[Algernon]

Limited experience here, but I found once the co2 has dissolved it seems to stay there even if the beer warms back up to ambient. I also found it seems to go into solution after under 48hrs in the fridge.

 

[markmark]

Gasses are more soluble in liquid at lower temperatures. This is why force carbonation is easier (quicker) at cooler temperatures given the same pressure applied to a keg at a higher temperature.
In theory, you would get a slightly higher concentration of co2 in a bottle conditioned beer at fridge temperature than you would at room temperature.....but I doubt you could notice it tbh.

The main benefit of longer conditioning is that the bubbles become smaller when liberated on pouring, and this should give you a tighter more stable head on the beer.

 

[NickW]

Gasses are more soluble in liquid at lower temperatures. This is why force carbonation is easier (quicker) at cooler temperatures given the same pressure applied to a keg at a higher temperature.
In theory, you would get a slightly higher concentration of co2 in a bottle conditioned beer at fridge temperature than you would at room temperature.....but I doubt you could notice it tbh.

The main benefit of longer conditioning is that the bubbles become smaller when liberated on pouring, and this should give you a tighter more stable head on the beer.

That's some great solid info :thumb:

 

[calumscott]

I understand the concept behind this, but does it work in practice?

No.

Think about what's happening in the bottle and where.

You have live yeast and sugar. The live yeast will produce alcohol and MOLECULAR (not gaseous; molecule by molecule, in water [effectively]) Carbon Dioxide.

The yeast needs to be somewhere nice and warm to do that, the downside is that the CO2 is less soluble at the warmer temperature. Eventually the beer becomes saturated with CO2 at room temperature and no more can dissolve. At this point, gas exchange will happen at the surface - CO2 is lost to the headspace.

The by product of that is increased pressure as we have a closed system.

The upside to that is that under increased pressure more Carbon Dioxide remains in solution. Fizzier. :thumb:

Let us now assume that the yeast has consumed the entire priming load and all the CO2 that can be created has been created. You effectively have a bottle of coke...

What happens if you stick a bottle of coke in the fridge? Not a hell of a lot.

What really happens is that the reduced temperature reduces the pressure (closed system and all that), and makes the CO2 a *little* more soluble in your beer. Warm it back to room temperature before serving and you're back to where you were before.

Serve it a little on the cool side though and you'll get a fizz that lasts better through your pint.

"Cold conditioning" though is a good thing. It seems to help the yeast to pack onto the bottom of the bottle better, it helps drop any last suspended particles out for a really clear beer and anecdotally at least, it seems to give a cleaner more "together" flavour to the beer.

 

[mike77]

Just because it's not cold doesn't mean it will be flat.

My understanding of forced carbonation is that it doesn't matter what temp the beer is at because the co2 has been forced into the beer under pressure. I don't think temperature has much to do with it.

With homebrewing and natural carbonation, if you can call it that, needs a warm period for the yeast to eat the priming sugar and convert it into co2, and the cold period to help the co2 dissolve into the beer.

When I said I have taken beer from my warm cupboard and chilled it I meant natural carbonated homebrew. Basically I have never cold conditioned my bottles for any length of time. If I remember to stick some in the fridge before going to work on Friday then Friday evening is usually the longest they will be in the fridge. I simply leave them in the warm cupboard and take them out as I need them and don't have any issues with carbonation. Sometimes if I need to cool one quickly it gets 10 minutes in the freezer and that is it. I don't think cold conditioning is necessary for carbonation unless you want to prevent champagne style gushers on a heavily carbed drink. Extended cold conditioning may be useful for other things such as clearing chill haze.

 

[honeymonster]

Basically I have never cold conditioned my bottles for any length of time. If I remember to stick some in the fridge before going to work on Friday then Friday evening is usually the longest they will be in the fridge. I simply leave them in the warm cupboard and take them out as I need them and don't have any issues with carbonation. Sometimes if I need to cool one quickly it gets 10 minutes in the freezer and that is it.

Thanks, that's good to know. I'm running out of space in my fridge and my fiance isn't to happy that we can't fit a lot of food in there at the moment

 

[Dr Mike]

Solubility of gasses in liquid can be estimated by Henry's Law (http://en.wikipedia.org/wiki/Henry%27s_law)

If you plug in the figures for Temperature variation in the formula the solubility of CO2 in water is about 30% higher at 'cool' temps (10C) than at room temp (20C). For a sealed bottle that means the headspace pressure (more correctly the CO2 partial pressure) will be 30% higher at room temp than at cooler temps. Because the volume of beer is so much greater than the volume of the headspace, the amount of CO2 migrating between the beer and the headspace as the beer cools or warms is going to be minimal. It just helps if the beer is cool when you uncap it.

It is still good practice to store bottled beer in the cool if possible though. It helps the yeast settle out and keeps flavour for longer.

 

[NickW]

So if I could summarise...

The "2 weeks in the cold" isnt necessarily necessary to help the beer absorb the co2 (because of the limited headspace in the bottle), so chilling down for an hour or so would have more or less the same effect ...

But...

Cold conditioning is obviously beneficial for the beer in terms of clarity and the conditioning / mellowing out of flavours..

 

[morethanworts]

It was simply my understanding that beer will absorb CO2 quicker if it's colder, because of the relationship between pressure and temperature. How much quicker, I don't know. As pointed out above, maybe it's negligible.

Yeast and particulates dropping out quicker is a separate benefit.

 

[calumscott]

The "2 weeks in the cold" isnt necessarily necessary to help the beer absorb the co2 (because of the limited headspace in the bottle)

Not quite, it has nothing to do with the headspace. It has everything to do with the dynamics of the secondary fermentation and the pressure created in the closed system at fermentation temperature. The cold conditioning will not affect the serving carbonation of your beer whatsoever, only the temperature at which you serve it will.

Cold conditioning is obviously beneficial for the beer in terms of clarity and the conditioning / mellowing out of flavours..

Almost certainly.

It was simply my understanding that beer will absorb CO2 quicker if it's colder, because of the relationship between pressure and temperature. How much quicker, I don't know.

Maybe, but that's not really the point. At any given temperature (and thereby pressure in a closed system) an equilibrium is pretty rapidly established whereby a finite volume of gas is in solution. This will not take weeks, while I don't know for sure, I'd say minutes or hours.

If *I* could summarise:

It is good practise to cold/cool condition your beer but it has nothing to do with the solubility of CO2 and everything to do with other physical, chemical and biochemical processes that make your beer look and taste better.