I have been home brewing for 8 years or so and I am suddenly having an issue with bottle conditioning. I have switched mostly to kegging but occasionally I still bottle a batch. I typically bottle 3-4 weeks after my brew day. All I do is siphon my wort into a bottle bucket with my priming solution and bottle.
Last night I had 6 bottles from a batch I did in the spring explode on me. I never had this issue before I started kegging everything. A lot of these bottles are bottles that have been sitting for a while, but I would have verified a stable gravity before bottling.
Maybe. I am not quite as diligent with that stuff but I do soak all that in sanitizing solution regularly. Maybe I need to give all my stuff a real good cleaning.
Too much pressure for the holding vessel is the cause of bottle bombs
Obvious, I know, but the truth. The question is then: what in the bottling process is leading to this outcome? It could be (micro)fractures in the bottle. It could be crappy bottle manufacturing on a handful you used for that batch. It could be that a bunch of bottle banged together at some point and weakened the glass. It could be too much priming solution was used. It could be that the priming solution wasn’t well distributed in your bottling bucket causing some bottles to get too much sugar, and other to not get enough. It could be a resilient sacc strain (var. diastaticus) is in your equipment. It could be a wild yeast (e.g brett), or a bacterial contaminant (as mentioned).
There are a lot of possibilities. Are the bottles actually overcarbed? Have you opened one at room temp (outside is best with gloves and eye protection) and seen the impressive gushing? If it doesn’t seriously gush out of the bottle then it may have just been a bottle issue, not a batch issue.
While testing a gushing bottle outside, pour some in a glass once the gushing slows down. How does it taste? Is it obvious contamination?
Extra cleaning and using bleach or iodine may solve the problem. However, you may have to retire some equipment as scratches are impossible to clean and sanitize and plastic is easily scatched.
And another great place to look for infections in bottles is right at the beer liquid/air interface in the headspace. Take a flashlight and shine it around the bottle in that location and look for tiny white little dots. That is an obvious indicator of classic infection.
On a side note - if you brew often you should be replacing your plastic equipment about once a year. Especially the softer plastic tubing and hoses. Fairly cheap and good assurance with new lines.
I should’ve been more accurate - I’m a kegger except for bottle filling for periodic comps, or an occasional bottle conditioned beer. Back when I did bottle strictly (decades ago), I always rinsed thoroughly with hot water right after emptying and visually inspected, and inspected again after sanitizing/before filling. I read the question more as ‘inspecting for crud before sanitizing’ (ie., cleaning before sanitizing) than as as question about using the dishwasher. Back then I cleaned then sanitized in a bucket of sanitizer. Now I just clean new bottles and sterilize in the oven @ 350F/ 60 mins since I don’t bottle enough to need to reuse bottles. Obviously need to read more thoroughly.
I agree with replacing tubing/plastics and giving your glass a bleach or quat rinse / Na or K-meta 20m soak / followed by sanitizer then bottle. Maybe switching to high temp silicone for your tubing isn’t a bad idea. I made the switch about 3 months ago when I found infection in the old bottling tubing that had soaked in iodine before getting put up in water tight containers.
