Question regarding how long to leave the beer to bottle carbonate and condition.
I read that it takes generally 2 weeks to carbonate. My question is can I leave it for longer like 3 weeks at temperature?
If I were to say have a batch of beer bottled but then had to go out of town and wasn't able to get it into the fridge for 3 weeks would this be a problem?
Let me clarify a few misconceptions in your post.
1. It only takes about 24 to 36 hours to carbonate your beer. However, at this point the beer will pour with no heading at all, just like your can of Pepsi.
2. If you do some testing you will discover that at a week your beer will form some head when poured but it will not last long.
3. Many variety of beers will be fairly mature at 3 weeks at room temperature, forming a good, long lasting head. This is not true of all varieties of beer. The darker the beer and the higher the alcohol content, the longer the beer will need to mature. My robust porter does not seem very robust until about 3 months at room temp. The "Deception Stout" I make was still improving at the end of the second YEAR but that was the last bottle.
4. I store my beer at room temp. It may be drunk fairly soon (IPA, Pale Ale) because of the oxidation that destroys the hop aroma but often spends several months at room temp.
5. Use your hydrometer to verify that your beer has completed fermentation. Two identical readings at least a day apart that are near or below the expected FG are needed. Once your beer has completed fermentation you don't have to worry about bottle bombs provided you calculate the proper amount of priming sugar and it gets well mixed before you bottle the beer.