Boom! 1L Flip Top Explosion

I should start with the disclaimer that this is my very first batch of homebrew.

Last night I had two 1L flip bottles explode. The bottom of the bottles blew out. As far as I can tell, I did everything correctly so I'm trying to figure out why I had an explosion. The beer is american pale ale and I used WLP001. The OG was 1.055 and after three weeks in the primary , the FG was 1.013. I bottled about 4.5gal last Saturday using 4oz of corn sugar. I disolved the sugar in boiling water and racked on top of that in the bottling bucket. I used three 1L flip tops and the rest were standard 12oz bottles. I left about .5-1" of headspace on each. Everything was santized with starsan. The flip tops were filled roughly midway through the bottling session.

They were stored in my basement about 62F for about 4 days and then I moved them upstairs to a 68F bedroom. These two broke about 36 hrs later. I've moved everything back down to the basement and so far, no other casulties.

I got the 1L bottles from my brother in law. He's probably had them for about 15 years, but has not bottled in them in over 11 years since he started kegging. They were stored up in his uninsulated attic. He's in Virginia, and it gets very hot up there in the summers. Is it possible that years of expansion and contraction might have resulted in hairline cracks that broke under pressure? Is it more likely I went awry somewhere in my process?

Wow. I'd be worried about the rest of the bottles. I don't think an attic can get hot enough to damage glass.

First thought was that you'd filled them last and these two got all the priming sugar, but you ruled that out already.

You say you sanitized with StarSan, how did you clean the bottles? Did you clean and sanitize the tops and gaskets, too?

I would be suspect of those bottles if you have any you did not fill. I would also pop the third one you did fill and see what the carbonation level is. If it is a big gusher or has something going on that might explain it. If it has a normal carb level similar to the 12oz bottles I would discard those swing tops and discontinue use.

I washed the bottles with soap and hot water. I used a vinator with about 5-6 pumps to cover the inside. I used brand new gaskets which were submerged in star san for 5-10minutes. I used a spray bottle to liberally coat the tops before I put on the gasket and then gave the neck a spray before closing it up.

I'm going to pop open the third one this evening. I'll report back with what I find.

E_Rock said:

I washed the bottles with soap and hot water.

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I'd bet dollars to donuts that's your problem. You can't sanitize something that isn't clean and dish soap won't get whatever might have been stuck on the inside of those bottles out. So you're out 2 nice bottles and 2L of your first batch, which really sucks, but you don't have a piece of glass embedded in your forehead, which is something to be happy about.

The best/easiest/only(for me) way to clean bottles is with Oxyclean Free or the cheaper generic equivalent. If you want to spend more money on the real stuff, you can get PBW (powdered brewery wash), but generic oxyclean works fine and costs less.

Please let us know how the third bottle is. Be sure not to agitate it at all prior to opening it, even turning from it's side to upright can agitate a beer (happened to me Wed. night). If it doesn't gush, I'd say it's the bottles. If it gushes, I'd lean towards infection. Might also pop a 12oz. and compare results of carbonation levels. If you're not using a bottle brush and/or bottle washer, get one or both and start using them. Oxy clean or PBW also do a great job of dissolving just about any organic material. I always rinse my bottles well after pouring beer from them and usually just soak in hot water/oxyclean and then inspect. If there's no gunk or residue, I sanitize and use.

ERock,
For your first beer, it sounds like you really know what you're doing. It says you joined on Nov 2011, so if you've been reading these forums that long, that would explain it.
If the 3rd 1 liter bottle is not a gusher then perhaps the bottles were very weak for some reason. If your Brother in law baked the bottles to sterilize them and did this many times, that might have weakened them (although I've heard differing opinions on this).
FWIW, Oxyclean is a great cleaner. Go get a big box at Home Depot or Walmart if you don't have it already.
P.S. Let me know where you are in NJ. I've been brewing for 1 year and always looking for nearby homebrewers to swap brews with.

I opened the third bottle last and I'm happy to report it was absolutely delicious! It was perfecty carbed, not a volcano.

So, TNGabe, I am thinking you nailed it. I soaked all of my other bottles in oxyclean in advance of bottling day. At the last minute, I decided to use the 1L bottles so I washed them right before in the sink using dish soap and a bottle washer for a hot water rinse. In hindsight, that's looking like quite the lapse in judgement.

Bridgewater, I was planning on begining brewing last year, but life got in the way and I didn't get to it. So I've done a lot of reading since then. Plus, my brother-in-law is a talented and experienced brewer, so I learned a lot from him, plus a few friends who also brew. He never baked the bottles and never had a bottle break on him before.

After giving all of the remaining 5 bottles a long soak in oxyclean, I'm going to use just one for each brew going forward. If none of them break, I think infection was the most likely culprit. If I have another disaster, I'll chalk it up to mechanical failure and discard the lot of them.

Glad no 3 was in good shape. I love those liter bottles for low abv fizzy beers like petite saison and berliner weisse. The 'pop' when you open was is such a great sound. I'm guessing you won't have this problem again.

Check YouTube for a video on cutting glass bottles. I think there is a good one by green science or something to that effect. He basically does what you mentioned only he was trying to break the bottle for a vase or something.

Thanks for update ERock. You're strategy makes we sense to me, im thinking infection also. If they were bad bottles they should have failed long ago. Bottle bombs are always interesting. I read somewhere that flip tops can handle several times more pressure than a standard glass bottle but that may be less true for a 1 L bottle.