Continually swapping kegs in fridge

[theSliver]

Hey guys,

Recently I've been getting back into the hobby big time and making a bunch of beer .

I currently have a kegerator that fits 5 corny kegs, but have 8 kegs of full of beer.

Because of the pandemic, I'm not getting through my supply as quickly as I used to. As a result, I've been moving styles in and out of the fridge. For example, I have an imperial stout that wasn't really getting drunk because of how hot this summer has been - so I replaced it with an IPA. I also replaced an ESB that wasn't getting much love with lager.

It struck me that this probably isn't great for the beer to be taken in and out of the fridge. What kind of negative effects - if any - could this cause?

 

[VikeMan]

The negative effect will be accelarated staling during the time the kegs are spending warm. Figure that staling reactions are happening 2-3 times faster for each 10 degrees celcius increase in temperature.

Of course, "good" reactions (like a big stout maturing, or sulfur compounds decreasing) also happen faster at warmer temps.

But in general, if the beer is at its peak (relatively young for most styles), there's only one way to go from there, and warmer temps will make it go downhill faster.

 

[Novims]

Almost every time I've removed a keg from the kegerator, it oxidised like crazy. I've ruined a beautifull Tripel that way, turning dark brown -and undrikable- in a matter of weeks, like if this process (from cold to hot) turbocharged the stalling reactions. It also seems hard on the keg's seal itself. Well, that's my experience.

 

[user 298779]

Hey Silver, I’m facing same situation. We’re still in trial stage trying to develop 4-5 recipes that will be our flagship beers. Been dumping a lot to allow new brews in 5 tap system.

Right now our space is severely limited so if someone provides good advice that’d be great. One thing I’m thinking is that once kegs are stabilized at room temps, purge with CO2 then pressurize at higher psi to maintain near serving carbonation levels. Haven’t tried it but just a thought. Might require a lot of CO2 though. Any thoughts??

 

[VikeMan]

One thing I’m thinking is that once kegs are stabilized at room temps, purge with CO2 then pressurize at higher psi to maintain near serving carbonation levels. Haven’t tried it but just a thought. Might require a lot of CO2 though. Any thoughts??

It takes the same amount of dissolved CO2 to carbonate a beer to "X" volumes, regardless of temperature. You'll need a higher PSI (consult a chart/calculator) to force all that CO2 into solution, but the total CO2 absorbed at equilibrium will be exactly the same.

 

[user 298779]

?? I’m not being a smart arse here but looks like you don’t understand my initial discussion. I refer you the attached chart. If you want 2.4 vols at 70 F you need a lot higher pressure to achieve that than at 34F.

 

[day_trippr]

If these kegs were carbonated to the desired level prior to removing from a dispensing system - and they are gas-tight wrt posts, poppets and O-rings (especially poppets and lid O-rings) - there is no need for "over-pressurizing" said kegs to maintain their carbonation level. They'll hold the carbonation level just like a capped bottle...

Cheers!

 

[user 298779]

Read what you wrote Vikeman, the comment was about the amount of CO2 you’d use from tank in the process. Don‘t know if it’d be significant or how long it’d take to achieve full saturation at 70F. As I said earlier, I haven’t tried it, so if someone has let us know. I could do some calculations but it’s not worth my time given someone on HBT likely knows already.

 

[user 298779]

If these kegs were carbonated to the desired level prior to removing from a dispensing system - and they are gas-tight wrt posts, poppets and O-rings (especially poppets and lid O-rings) - there is no need for "over-pressurizing" said kegs to maintain their carbonation level. They'll hold the carbonation level just like a capped bottle...

Cheers!

Thanks DayTripper. Hadn’t thought of that. While it’s a closed system gas laws still apply (I.e. PV=nRT). Maybe you haven’t seen this, but with small CO2 bottles (5 lb) the psig raises significantly when moving from 34F to 70F. I don’t have a gauge calibration process and a bourdon gauge can be inaccurate it’s still true in principle. Correct me if I’m wrong, please.

 

[VikeMan]

Read what you wrote Vikeman, the comment was about the amount of CO2 you’d use from tank in the process. Don‘t know if it’d be significant or how long it’d take to achieve full saturation at 70F.

As I said, the total dissolved CO2 needed to reach your target CO2 volumes will be exactly the same, regardless of temperature.

As I said earlier, I haven’t tried it, so if someone has let us know. I could do some calculations but it’s not worth my time given someone on HBT likely knows already.

I have carbonated at room temp. You don't have to "do some calculations." Just look at a chart to find the PSI needed. Higher PSI does not mean more CO2 will be used. You are confusing pressure with mass.

 

[day_trippr]

[...]Maybe you haven’t seen this, but with small CO2 bottles (5 lb) the psig raises significantly when moving from 34F to 70F. I don’t have a gauge calibration process and a bourdon gauge can be inaccurate it’s still true in principle. Correct me if I’m wrong, please.

I've probably posted this image a hundred times, so yes, I know about CO2 pressure vs temperature

But the above is actually completely irrelevant wrt carbonation of beverages in sealed containers. We literally don't care!
Carbonation levels do not change with temperature! Once 2.5 volumes, always 2.5 volumes!

Cheers!

 

[user 298779]

If these kegs were carbonated to the desired level prior to removing from a dispensing system - and they are gas-tight wrt posts, poppets and O-rings (especially poppets and lid O-rings) - there is no need for "over-pressurizing" said kegs to maintain their carbonation level. They'll hold the carbonation level just like a capped bottle...

Cheers!

 

[user 298779]

Great chart, thanks I didn’t say “over-pressurizing”, but while the keg pressure will remain the same, the CO2 will come out of solution with significant temperature rises??

The vols in keg remain same but saturation does not, or are you saying the pressure differential incurred with temp increasing will keep solution at same saturation? I was thinking pres would need to be added to maintain same vols. But now considering PV=nRT, assuming n, R, V remain the same, P increases proportionally with T.

So another consideration for me is carbonation to 2 vols CO2 for bitters at 36F then I can’t use serving pressure at 10-12 psi without warming keg in different chamber at higher temp. ??