Here are the results of a quick bottle carbonation experiment. How long should you wait before putting your beer in the fridge?
I recently received a comment on an old post about flat beer asking why a batch of home brew had failed to carbonate.
There was a key piece of information: the beer only had 4 days to carbonate before being put in the fridge.
I assumed that it had been chilled too soon, before carbonating properly. But after replying I realised I’d given advice based on instinct rather than experience.
So I decided to test the theory.
As I was about to bottle a batch of saison, I set up a mini-experiment. After priming the beer as usual, I added one bottle of it to the fridge every three days for two weeks.
Would the bottles that went in earlier be less carbonated and flat?
I’ve written about priming sugar and carbonation before, so I’d suggest reading that if you don’t know what it’s all about.
For this beer, I added enough priming sugar for medium carbonation. That means I expected a reasonable but not excessive amount of gas and head.
Bottle Carbonation Experiment Results
To see the results, I poured all the beers straight into the centre of the glass, aiming for the most head possible.
In an attempt to generate suspense, I’ll go through them in reverse order.
Carbonated 15 Days/In Fridge F0r ½ Day
The beer that had the full fifteen days at room temperature was nicely carbonated with a decent head and a pleasant gassy mouthfeel.
About right in terms of carbonation, although the beer itself needs a bit longer for some of the flavours to settle down.
Carbonated 12 Days/In Fridge For 3 Days
This beer had carbonated too well. It looked like I’d overprimed it.
Carbonated 9 Days/In Fridge For 6 Days
Although with less gas than the first beer, this was still OK and quite nice to drink.
This was the cut-off point I think.
Carbonated 6 Days/In Fridge For 9 Days
Another overprimed one, an anomaly I think rather than a result to later be relied on.
It goes to show how variation from beer to beer is part of home brewing.
Carbonated 3 Days/In Fridge For 12 Days
Just three days of carbonation at warm temperatures gave the beer enough time to develop gas and foam.
However, the head and fizz were short lived.
Carbonated 0 Days/In Fridge For 15 Days
Unappetising and flat, the beer that went straight to the fridge seemed to confirm the theory. Bottle carbonation is best done at room temperature.
Something that hasn’t come through in the photos is the differences in colour. The 0 and 3 day beers were muddy orange/brown, whereas the more carbonated ones were bright and punchy yellow.
I hadn’t expected colour to be affected so much.
Although it may seem like there’s not a lot of difference, if you look at them all together you can see that the amount of head increases the longer they were carbonating outside the fridge.
Even the longer carbonated of the overly-gassy ones had more foam than its friend.
I’ve always treated two weeks as the minimum carbonation period and this test hasn’t changed my mind on that, even though you could probably get away with less.
The increased staying power of the foam convinced me it’s worth waiting the full fortnight.
There’s nothing particularly surprising about these results. In fact, here’s what the Yeast book says:
The way you store the beer also affects the degree of carbonation. If you store the bottles too cold, the yeast will not actively metabolize sugar and create CO2.
Although it was perhaps inevitable, it’s good to see my assumptions confirmed in reality.