Can I increase the carbonation of already-bottled beer?

Question

I just made my first ever batch of beer, and it turned out great! The only thing is that my priming sugar calculation was slightly under what it should have been. I added 1/4 cup honey to a (finished volume) 2.5-gallon batch, and I should have been closer to 1/3 or 1/2 cup.

The beer is carbonated, but it could use a little more. Is there any way to increase the carbonation? I.e. by, in a sanitary environment, opening the bottle, adding a bit more priming sugar, and re-capping? Assume that I have enough head space to actually do that (I do, because I was afraid of my bottles exploding so I left a bit more than I needed to).

I'm happy with how the beer turned out regardless, so it's not a big deal. In my next batch I can just increase the amount of priming sugar. But bubbles are nice, so I'm curious: can I increase the carbonation of already-bottled beer?

Answer 1

I have such experience, and it's possible: there is, almost always, enough yeast in the bottle to process the extra priming sugar.

A few things to check before you try and do it: - are you sure all priming sugar has been consumed and turned to CO2? It takes a at least couple of weeks for bottled beer to properly condition; - does it make sense at all? Unless you're going to enter a competition of sorts, drink it as it is.

Side note: honey is a lousy priming sugar, because of its unpredictability. Use either table sugar (sucrose) or cane sugar (aka glucose/dextrose).

Now, to the process. Don't try to add dry sugar or carbonation drops, or your beer will start foaming right from bottles. Instead, make a sterile rather concentrated sugar syrup, where you know sugar contents per ml. Say, 0.5 gram per ml -- then you know, for example, that you can add 3 ml to each bottle. You're gonna keep the syrup hot, otherwise the dissolved sugar may precipitate. Get a sterile syringe. Chill your bottles very well. Then open each bottle, quickly add syrup and close it immediately. Leave bottles for another week or two.

Answer 2

Yes, maybe. You can add a measured amount of sugar and that can increase your carbonation but you're inviting other problems. 1. The yeast may have temporarily stalled out, and if it takes off again it could ferment the existing unused sugar plus the new stuff, creating the potential for bottle bombs. 2. You could miscalculate the amount to add, also creating the potential for bottle bombs.
3. You're adding one more chance for infection, which has its own hazards.

All of this also assumes that your yeast hasn't stalled out due to high ABV. One way to encourage your yeast to do a bit more work is to store your bottles somewhere fairly warm for a while. Probably not in direct sunlight, but the mid 80s would be no problem. With the tiny bit of fermentation being done, you won't notice it in the flavor.

Answer 3

Maybe yes, Depends on how much yeast is left in the bottle and how much risk you want to take.

Easiest way is add a carbonation drop into each bottle and recap. Next would be to add maybe half a teaspoon of sugar or honey to each bottle.

This does have some issues, if the carbonation drop is meant for 12oz bottle then this could over carbonate, and both have issues of introducing other things to your beer. both could create bottle bombs.

My suggestion is drink as is, and next time add more priming sugar. If you happen to add sugar or carb drops, test on one or two bottles.