Bottle Bombs... Again!

[cernst151]

OK, I feel like I've done everything and I'm completely at a loss. Maybe somebody here can help. I've brewed 40-50 batches (didn't keep great notes in the beginning and missed several since so I don't have an exact number) and have had overwhelming success. I even brewed about 15 batches for my wedding and they all came out great.

A year or two ago I made a mocha stout that produced a lot of bottle bombs and eventually I got dressed up in protective gear, popped the bottles and saved what I could into growlers to drink. I blame that one on not giving enough time for the sugar in the chocolate to ferment. After that, I didn't have a problem for about 20 batches.

Lately I've had a string of a few (but not all) batches producing bombs. Most recently I brewed 4 batches in 2 weeks. The IPA and red turned out great. The stout, and parti-gyle were heavily over carbonated and the parti-gyle was bad enough that a few exploded and last night I popped the tops and poured it all out. Very sad but at least it was a parti-gyle so essentially free. The Stout has had 1 explosion and the others I've tried are way over carbonated.

So, here's the relevant info. All are AG. On all 4 batches I tested the gravity and between testing it when I moved it to secondary and a test 1 week later the gravity stayed stable. Since I'd had some problems in the past I was very careful to move the beer into the bottling bucket first to get a measurement of how much beer I had and instead of using my standard amount of DME I downloaded the app Brewers Friend and calculated how much DME to prime with and stirred well. It seemed like too much but that's what the calculator told me to use. I'm sorry but I don't have the amount recorded because I couldn't find my diary that night. I chose a volume right in the middle of the recommended for the style, and since they're stouts they were on the low end anyway.

Still, several of the parti-gyle's exploded and 1 stout. I'm out of ideas and almost afraid to brew another batch, or even open one of the stouts. Should I use a different priming calculator? Should I switch back to priming sugar? Is there another way to tell if everything's fully fermented other than hydrometer readings a week apart? Please help!

 

[mcspanner]

The only thing I can think is that, although the FG was " stable" there was still some fermenting to do and racking it, priming it and stirring roused the yeast in to a second wind to finish it off. When you said it was stable, do you remember the FG reading?

Either that or there was an error in the dme calculation and it got inadvertently over-carbed.


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[mcspanner]

Actually, that's two things I can think of. No-one expects the Spanish Inquisition!


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[JimRausch]

With 40-50 batches under your belt, you know about the 3 standard reasons for bottle bombs, and are hopefully working on these- 1. underattenuation before bottling, 2. too much priming substance, and 3. infection. I'm going to add 2 more: weak bottles, and too-vigorous crimping. I've had 2 bottles in an otherwise normal batch just split off the bottom of the bottle, and in a different batch, several cracked necks that wasn't apparent until opening.
You are weighing your DME rather than going by volume measure, right?

 

[renrutle]

Can you post how much DME you used and the volume of each batch? Even a WAG (wild a$$ guess) would help.

What was your storage temperature for the bottles?

As a ballpark, a Stout (or other beer) at 2.0 vloumes of CO2 should require about 4.25 oz of DME (3/4 cup) for a 5 gallon batch. Going to 3 volumes doubles the DME to almost 8 oz or 1.5 cups. (using Northern Brewer online calculator).

A well capped bottle should hold 3 voulmes.

Are you using this much? When I bottled I used 4oz of dextrose for a 5 gallon batch. You will need more DME than dextrose to get the same carbonation level.

Another thought I had is that there may be a problem with your capper.

 

[flars]

Do you primary until final gravity is reached and then a few more days for the yeast to clean up?

 

[cjgenever]

Do you primary until final gravity is reached and then a few more days for the yeast to clean up?

This^

And do you have temp control on your fermenter? Taking off a cake too soon in conjunction with temp swings can stall a ferment.

Since you have been successful with many other brews I would look for intermittent infection... The ones caused by process rather than infected equipment. Or maybe you had one too many that night and screwed up the measurements?

After some occasional gushers I began 'scrubbing in' before bottling. I use a hair net, elbow length gloves (starsan is rough on the hands anyway), and a dust mask (un valved, the valved ones don't filter on the exhale). I have also been using twice the amount of starsan while spraying my bottles and keeping them upside down or covered. I only uncover for at a time while I fill. Only one if I have an assistant. No more gushers.

 

[cernst151]

With 40-50 batches under your belt, you know about the 3 standard reasons for bottle bombs, and are hopefully working on these- 1. underattenuation before bottling, 2. too much priming substance, and 3. infection. I'm going to add 2 more: weak bottles, and too-vigorous crimping. I've had 2 bottles in an otherwise normal batch just split off the bottom of the bottle, and in a different batch, several cracked necks that wasn't apparent until opening.
You are weighing your DME rather than going by volume measure, right?

Yup, I'm aware. For the vast majority of my batches over the years I've measured my priming sugar and priming DME by the cup. These last 4 batches (half of which are having the problems) I measured by weight.
1) I tested the gravity 2 days in a row before moving to secondary and after a week in secondary the measurement was the same, or at least within the same bar on the hydrometer.
2) It did actually seem like the calculator told me to use more priming DME than I expected. I just trusted the calculator.
3) The stout tasted good so I don't think it's infection. The Parti-gyle tasted bad but I chalked that up to first time experiment/weak light stout.
4) I also thought about the weak bottles but they're definitely seriously overcarbed too. It even blew up one of my pop-top Grolsch bottles and I've never seen one of them blow.
5) I hadn't considered this one but I would expect it would blow at the neck if that were the case. Most of these the neck blew clean off.

 

[Hello]

If it blew a flip top then that's a pretty big issue. Are you sure you're bottling the volume you are entering into the calculator? Also, if you think the DME amount is high then lower it. Go with your gut. I've done that numerous times because to me at some point it seemed like it was too high. Also, always measure by weight and not volume as you may now know.

 

[cernst151]

Can you post how much DME you used and the volume of each batch? Even a WAG (wild a$$ guess) would help.

What was your storage temperature for the bottles?

As a ballpark, a Stout (or other beer) at 2.0 vloumes of CO2 should require about 4.25 oz of DME (3/4 cup) for a 5 gallon batch. Going to 3 volumes doubles the DME to almost 8 oz or 1.5 cups. (using Northern Brewer online calculator).

A well capped bottle should hold 3 voulmes.

Are you using this much? When I bottled I used 4oz of dextrose for a 5 gallon batch. You will need more DME than dextrose to get the same carbonation level.

Another thought I had is that there may be a problem with your capper.

OK, here's my WAG. Actually, I'm just using the same calculator I used before and going by what I remember of how much beer and the volume I used.

Parti-gyle - 2.5 gallons - 2.0 volume - 2.6oz DME
Stout - 3.5 gallons (it's a peanut butter stout so we had a lot of loss from the powdered peanut butter) - 2 volume - 3.6oz DME

It occurs to me, do different DME's have different amounts of fermentable sugars in them? I think I'm using Breiss Golden Light DME.

 

[BeerGrylls]

Forgive me if someone mentioned this already, but you may have an infection in your bottling setup that is causing further fermentation in the bottle. With that in mind I'm sure you can isolate and test your bottling bucket, wand, hoses, caps, etc, etc. Edit: I see that you already dismissed that idea, but I would caution against outright dismissal based on taste. There are some bugs and wild yeasts that can cause bottle bombs before they really begin to change the flavor dramatically, especially if they're being introduced after your sacch ferm is already complete.

 

[cernst151]

This^

And do you have temp control on your fermenter? Taking off a cake too soon in conjunction with temp swings can stall a ferment.

Since you have been successful with many other brews I would look for intermittent infection... The ones caused by process rather than infected equipment. Or maybe you had one too many that night and screwed up the measurements?

After some occasional gushers I began 'scrubbing in' before bottling. I use a hair net, elbow length gloves (starsan is rough on the hands anyway), and a dust mask (un valved, the valved ones don't filter on the exhale). I have also been using twice the amount of starsan while spraying my bottles and keeping them upside down or covered. I only uncover for at a time while I fill. Only one if I have an assistant. No more gushers.

Wow, mask and gloves. That's a special level of anal retentive. HA! I suppose it could be bad breath infection. I'll try that next time.

Unfortunately I don't have a fermentation temperature control yet but I'm looking to buy one. I've been keeping an eye on Craigslist for a freezer and I'm on the list to buy one of the next batch of Black Box controllers. I know I've had temperature control issues in my basement.

 

[cernst151]

If it blew a flip top then that's a pretty big issue. Are you sure you're bottling the volume you are entering into the calculator? Also, if you think the DME amount is high then lower it. Go with your gut. I've done that numerous times because to me at some point it seemed like it was too high. Also, always measure by weight and not volume as you may now know.

I know! When the other bottles went I was disappointed. When a flip top blew, I poured the rest out. My wife and I bottled all 4 batches the same night and I don't think I had even 1 beer to drink that night so I wasn't drunk. Maybe that was the problem, I was too sober to brew. HA. It is possible I was just tired after bottling so many and screwed the measurements up.

I considered cutting it down since it looked like too much but this was the first time I've used the calculator and the first time I've measured priming DME by weight so I just wanted to use the calculations I was given.

 

[ArcaneXor]

How do you sanitize?

Degass a few of these overcarbonated bottles and pour them into a sanitized gallon jug (with airlock). See if anything happens. Measure the SG occasionally and see if it drops. That would indicate infection as the cause.

Are all bottles in a batch affected, or are some overcarbonated while others are fairly flat? That would indicate the DME is not well-mixed in the bottling bucket. I would recommend going back to priming with dextrose either way. In my personal opinion, it's easier to work with, faster, and more reliable (easier for the yeast to ferment).

Do you use yeast nutrients? How do you aerate the beer? Do you make yeast starters? What does your fermentation temperature profile look like? How many weeks do you keep the beer in primary?

 

[cernst151]

Forgive me if someone mentioned this already, but you may have an infection in your bottling setup that is causing further fermentation in the bottle. With that in mind I'm sure you can isolate and test your bottling bucket, wand, hoses, caps, etc, etc. Edit: I see that you already dismissed that idea, but I would caution against outright dismissal based on taste. There are some bugs and wild yeasts that can cause bottle bombs before they really begin to change the flavor dramatically, especially if they're being introduced after your sacch ferm is already complete.

I considered that but since I bottled 4 batches in one night, if it were equipment infection I would expect all 4 batches to be blowing.

 

[flars]

It does not seem your problem is the amount of priming sugar used. Seems infection is more likely.
Has there been any changes in procedures?
Change in boiling the priming sugar solution?
Change in rinsing bottles after pouring, inspection/cleaning, or sanitizing? Do you use a no rinse sanitizer?
The four batches that were bottled on the same night, was there a fan in the area which could have infected the bottling bucket with wild yeast?

 

[cernst151]

How do you sanitize?

Degass a few of these overcarbonated bottles and pour them into a sanitized gallon jug (with airlock). See if anything happens. Measure the SG occasionally and see if it drops. That would indicate infection as the cause.

Are all bottles in a batch affected, or are some overcarbonated while others are fairly flat? That would indicate the DME is not well-mixed in the bottling bucket. I would recommend going back to priming with dextrose either way. In my personal opinion, it's easier to work with, faster, and more reliable (easier for the yeast to ferment).

Do you use yeast nutrients? How do you aerate the beer? Do you make yeast starters? What does your fermentation temperature profile look like? How many weeks do you keep the beer in primary?

Interesting idea. I hadn't thought about putting a few back in a jug to "bulk age" them to test the infection idea. I may give that a shot.

All of the bottles in the parti-gyle batch were violently overcarbed. All of the stouts were very overcarbed but not quite as bad as the parti-gyle, though I had 1 explosion in this one too. I think I will go back to dextrose at least for a while. I definitely noticed an improvement in mouthfeel when I moved from dextrose to DME but it's probably time to go back to basics.

I aerate by pouring bucket to bucket a few times. I do make yeast starters. You bring up one interesting point. I added some yeast nutrient into secondary to avoid this problem. I hoped that would get them moving again to finish off any fermentables then left them in secondary for about 2 weeks. Now that I think of it I only added the nutrients to the 2 batches that have had the problems.

All 4 fermented a little high, in the low-mid 70's for about 2 weeks then sat in secondary for another 2 weeks.

 

[cernst151]

It does not seem your problem is the amount of priming sugar used. Seems infection is more likely.
Has there been any changes in procedures?
Change in boiling the priming sugar solution?
Change in rinsing bottles after pouring, inspection/cleaning, or sanitizing? Do you use a no rinse sanitizer?
The four batches that were bottled on the same night, was there a fan in the area which could have infected the bottling bucket with wild yeast?

The only changes in procedure are using a priming calculator, using a scale to measure and racking the beer into the bottling bucket first to get an accurate measurement of the beer I was bottling. All of those changes should reduce the risk. Then I poured the boiled DME in and stirred thoroughly. I rinse everything in starsan and run it through the auto siphon, hoses and bottling wand. No fan.

 

[flars]

Was the yeast nutrient boiled then added?

 

[ArcaneXor]

It's definitely difficult to identify the problem based on the information. I suggest doing the test to determine if an infection is at work, and in the meantime, using nutrient in primary, leaving the beer in primary for longer, and starting the ferment cooler, letting the temperature rise after about 4-5 days to help maximize attenuation. If you are not familiar with swamp coolers, look up what they are and use one to start your ferment around 66-68 degrees and keep it there for 4-5 days before letting it ramp up to ambient.

 

[cernst151]

Was the yeast nutrient boiled then added?

Yes, I boiled the nutrient first, put it in the carboy and racked the beer on top to get a good even mix.

 

[cernst151]

It's definitely difficult to identify the problem based on the information. I suggest doing the test to determine if an infection is at work, and in the meantime, using nutrient in primary, leaving the beer in primary for longer, and starting the ferment cooler, letting the temperature rise after about 4-5 days to help maximize attenuation. If you are not familiar with swamp coolers, look up what they are and use one to start your ferment around 66-68 degrees and keep it there for 4-5 days before letting it ramp up to ambient.

Sounds good. I'll be brewing again as soon as I can get some good temperature controls going. When I do I will definitely leave it in primary longer at the correct temp and then let the temp rise. The next brews I'm going to just take the whole process slower and focus on the details. I'll also make sure to have my wife and/or one of my brewing buddies along to double check all of my details. Maybe I'm just getting sloppy somewhere along the line.

 

[Hello]

I know! When the other bottles went I was disappointed. When a flip top blew, I poured the rest out. My wife and I bottled all 4 batches the same night and I don't think I had even 1 beer to drink that night so I wasn't drunk. Maybe that was the problem, I was too sober to brew. HA. It is possible I was just tired after bottling so many and screwed the measurements up.

I considered cutting it down since it looked like too much but this was the first time I've used the calculator and the first time I've measured priming DME by weight so I just wanted to use the calculations I was given.

My worst brew day which resulted in 5 gallons down the drain happened when I was 100% sober. Never again.

 

[fartinmartin]

This isn't something I do, but, I have never taken an SG reading after I have primed. That would qualify the amount of priming you have used wether it be sugar or DME. This would immediately qualify what we are bottling. Maybe I will give it a try, but then I have only ever had one bottle go, and I am adamant that that was a weak bottle.

 

[Sir-Hops-A-Lot]

If I were you I'd consider replacing my siphon. I think that it is a common cause of infections. Sanitize it before every use.
Also consider getting a new bottling bucket.
The gyle priming sounds like trouble too.
Another problem source is giving away beer and having people give you back the bottles. Few people realize how well they have to be rinsed.

 

[cernst151]

After another explosion I decided to pour out the stout. I chilled them to near freezing, carefully put them in the sink and popped the tops one at a time. The resulting foam geyser completely emptied the bottles. Very sad.

What's really strange is that there were 2 perfectly carbonated bottles in the bunch. They were delicious and somewhat alleviated my sadness.

 

[cjgenever]

If there were two good bottles then the problem is very likely dirty bottles. You would be amazed how small of a particle will ruin a bottle. Every one of my bottles gets cleaned immediately with a pressure bottle washer. If not, it gets a 24 pbw pbw soak and full inspection. This is the only way I can avoid inspecting every bottle.

 

[rupert130]

If you bottled 4 batches in one night, did you clean and sanitize bottling equipment between each batch? If you bottled a beer that had a more highly attenuative yeast strain first, you may have "infected" your subsequent batches with a different strain of brewers yeast.

 

[cjgenever]

If you bottled 4 batches in one night, did you clean and sanitize bottling equipment between each batch? If you bottled a beer that had a more highly attenuative yeast strain first, you may have "infected" your subsequent batches with a different strain of brewers yeast.

True, but I think the fact that some bottle from the same batch are not infected is a big clue here...

 

[helibrewer]

Did you use the same base malt for all of the problematic batches?

 

[cernst151]

If you bottled 4 batches in one night, did you clean and sanitize bottling equipment between each batch? If you bottled a beer that had a more highly attenuative yeast strain first, you may have "infected" your subsequent batches with a different strain of brewers yeast.

Rupert, you just won the internet! Congratulations!

HA! I've been racking my brain on this for weeks, and plenty of other people have chimed in. I was a little worried about not sanitizing between batches but I figured it should be fine since none showed any sign of infection. It never even occured to me that I'd be "infecting" the last 2 batches with the yeast from the first 2. I suppose if I'd bottled in the other direction it wouldn't have been a problem.

The IPA and the Red both used Wyeast 1056 (attenuation: 73-77%) while the stout and second runnings used Wyeast 1187 (Attenuation: 68-72%). That left those 2 batches with a spare 5% sugar for the yeasties to eat.

Thank you Rupert. If you're ever near the Twin Cities, I owe you a beer.