Bottle bombs

I usually keg but decided to bottle a batch recently. I havent bottled in a year or two but Im pretty sure I did it the way I always did. I sanitize the bottles with starsan. The beer was definitely done fermenting. It went a couple weeks at 65 in my temp controlled freezer then at room temp for a couple more weeks. The finished gravity however was only down to 1.022 from 70. I expected it to go lower but wrote it off to high mash temp.

I had just about exactly 5 gallons and bottled with 3/4 cup corn sugar. Some are starting to blow so I am chilling them.

Would this be from the residual sugar in the beer? Infection? I dont get it.

Sounds like more fermentation in the bottle to me. You could degas a bottle and take a gravity reading to be sure.

This happened to me last year with a stout I was sure was finished at 1020. I had done a fast ferment test that finished there, even. A few bottles started to blow, so I took a reading on one and they had gone to 1014.

My guess is that either your fermentation stalled out at some point, and you ended up rousing the yeast at bottling time which renewed fermentation, or you didn’t mix the priming sugar well and some bottles got too much and are causing bombs… Check your gravity. If it’s renewed fermentation, it should be well below your 1.022 FG. If it’s in the 1.022 range, then it’s probably a priming sugar issue.

If it’s renewed fermentation, you could pop the caps on the bottles, cover them with a sanitized piece of foil, and let them finish up fermenting at room temp. Then you can re-prime the bottles and try again.

This has happened to me on a couple batches, each time with yeast that flocculate out really well. I didn’t have bursting bottles, just way over carbed beer. I now keg everything and prime my kegs with sugar towards the low side of the carbonation I want. I can then boost carb with CO2 if I end up wanting higher carbonation and bottle from kegs. A bit of screwing around since I bottle from the keg (i’m just using a cut off bottle filler tube shoved in to a picnic tap) but with cold bottles I’ve gotten pretty good at filling from the keg.

Of course I could just secondary beers that I plan to bottle to make sure an refermentation happens in there but I very rarely bottle and it is kind of nice to have precise control over the carb level of my bottled beer.

[quote=“Flip”][quote=“erockrph”]

Of course I could just secondary beers that I plan to bottle to make sure an refermentation happens in there but I very rarely bottle and it is kind of nice to have precise control over the carb level of my bottled beer.[/quote][/quote]

This is exactly why I started kegging, its also nice to be able to force-carb if I need to get a beer out sooner.