How can you tell if your beer is carbonating in the bottle?

[NSMikeD]

I try to use one swing-top bottle in each batch. About two weeks, in, I'll crack the swing top and pour off a small sample, then re-seal. That way you can take progress tastings without ruining a whole bottle.

keep in mind that this exposes the beer to oxygen and that the increase in head space can lower the carbonation equilibrium pressure resulting in off flavor and flatter beer than the beer in unopened bottles.

 

[Mainer]

keep in mind that this exposes the beer to oxygen and that the increase in head space can lower the carbonation equilibrium pressure resulting in off flavor and flatter beer than the beer in unopened bottles.

Yeah, I know. But it's just my test bottle. I don't expect for that one to be representative of the batch, just an indication of how it's progressing.