How do I know when bottle carbonation is done?

If you don't want to relax, keep calm and wait 2 more weeks to drink your homebrew, you can open one bottle every time you think its done. But it will cost you so much flat beers. The best option is wait.

If you want something to monitor your carbing without open bottles every time, you can use a bottle pressure gauge to measure the pressure of one sample bottle.

_{(source: instructables.com)}

There is adaptors to many types of bottles. There is a link with a instructable of this example above.

Or you could fill one plastic bottle. While the yeast produces CO2, the bottle turns more pressurized. PET bottles allow you to squeeze it and see how much you can deform it. If you do this in every batch, you will learn the right time to open the other ones.

There is a question about that here in stackexchange: Is there anyway to tell if a glass bottle of beer is carbonated without opening it?

Use the search to find what you want here before ask.

(:

Good luck!

Ideal method; after 2 weeks, take one bottle and stick it in the fridge over night. The following day, open it and pour a glass. If it is flat or under carbonated, wait a few days or another week, and repeat the process until you are happy with the carbonation. If there is some reason to suspect over carbonation (you think you used too much priming sugar or you bottled before fermentation was complete, or you are new); use shorter intervals, like start after one week and if you find it is overcarbonated, move the entire batch to the fridge to help prevent exploding bottles. In my experience, the carbonation is different at serving temps so it's important to allow the bottle to chill. In some cases, it will change even more after 48 hours in the fridge, so might be a good idea to put 2 bottles in, taste one after 24 hours and one after 48 hours.

It usually takes 2 weeks for the beer to carbonate in the bottle. There's no way of knowing if the beer is carbonated from only looking at it, I mean, some times you could see some bubbles inside but it's not always the case.

So just wait for 2 weeks and open a bottle... There you will know...