Help me diagnose my bottle bombs

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

bigmike86

Well-Known Member
Joined
May 19, 2016
Messages
60
Reaction score
5
Bottled my Citra Pale Ale about 6 days ago, and my impatience finally served me well. First tester was an exploding champagne-like experience! Actually shot half way across the living room... Opened a few more and had similar results, although some were better than others.

In the mean time, I put them in the lager chamber to try to settle down and maybe salvage a few (is that a good idea?)

Here's what I did on this brew. First, I fermented with English Ale yeast, and wasn't happy with the attenuation so I added a little dry English ale at the end as a personal experiment (and was washing that yeast that day so it was pretty convenient). Then I dry hopped cascade and citra for a few days while waiting on my American Flag bottle caps (4th of july!). I dry hopped without any hop bags and when I racked to a bottling bucket I ran it through a strainer, sucked up some hop sludge and didn't let it settle (again was tired and lazy). Bottled to estimated 2.5 vols with cane sugar (definitely measured correctly).

Here is what I think may have happened

A. Yeast addition laid dormant until I bottled which oxygenated and kicked off further fermentation
B. Hop bits and yeast sludge caused some extra reaction in bottles?
C. Some other weird thing I am not considering.

Thanks and sorry for the long response! Also, beer tastes great after I lose 2/3 of it to the explosion, so I don't think funky bacteria caused it.
 
Also wanted to add that the carbonation volcano seems to be coming from small yeast chunks on the bottom. Not sure where they came from, was mostly clear when I bottle minus the small amounts I sucked up.
 
OK no worries, thanks for the direction. All of the following laziness is not usual for me, I brewed my buddy an IP right before and doing everything twice by myself really wore me out!

Heat wave kicked in right after brew, so fermentation was around 76 degrees for 3-4 days then cooled down to around 68 for another week and a half (I know, I know... chamber was used up for lager and we don't have AC in the pacific northwest)

OG was 1.055 and FG before bottling was 1.013.
 
Extra yeast won't cause more CO2 to be generated, unless something killed your original yeast prior to fermentation being complete. Bottle bombs/gushers are caused by bottling before fermentation is complete, using too much priming sugar, and/or infections. In the first two cases, you get too much CO2 because you had too much unfermented sugar in the beer when you bottled. In the third case, the bugs can ferment dextrins that cannot be fermented by the yeast, leading to more CO2 generation.

You can also get excessive foaming on opening if the beer isn't chilled. CO2 will escape out of warm beer much faster than out of cold beer.

Chilling your bottles will slow down any continuing fermentation, reducing the build up of additional excess CO2. Chilling will also lower the internal pressure in the bottles, reducing the chance that they might explode.

Brew on :mug:
 
Extra yeast won't cause more CO2 to be generated, unless something killed your original yeast prior to fermentation being complete. Bottle bombs/gushers are caused by bottling before fermentation is complete, using too much priming sugar, and/or infections. In the first two cases, you get too much CO2 because you had too much unfermented sugar in the beer when you bottled. In the third case, the bugs can ferment dextrins that cannot be fermented by the yeast, leading to more CO2 generation.

You can also get excessive foaming on opening if the beer isn't chilled. CO2 will escape out of warm beer much faster than out of cold beer.

Chilling your bottles will slow down any continuing fermentation, reducing the build up of additional excess CO2. Chilling will also lower the internal pressure in the bottles, reducing the chance that they might explode.

Brew on :mug:

Thanks! I see you're from renton, so you might know the heat wave I speak of (about 3 weeks ago). Actually gave the IPA some good fruity notes to compliment the extra bitter hops.
 
Bottled my Citra Pale Ale about 6 days ago, and my impatience finally served me well. First tester was an exploding champagne-like experience! Actually shot half way across the living room... Opened a few more and had similar results, although some were better than others.

In the mean time, I put them in the lager chamber to try to settle down and maybe salvage a few (is that a good idea?)

Here's what I did on this brew. First, I fermented with English Ale yeast, and wasn't happy with the attenuation so I added a little dry English ale at the end as a personal experiment (and was washing that yeast that day so it was pretty convenient). Then I dry hopped cascade and citra for a few days while waiting on my American Flag bottle caps (4th of july!). I dry hopped without any hop bags and when I racked to a bottling bucket I ran it through a strainer, sucked up some hop sludge and didn't let it settle (again was tired and lazy). Bottled to estimated 2.5 vols with cane sugar (definitely measured correctly).

Here is what I think may have happened

A. Yeast addition laid dormant until I bottled which oxygenated and kicked off further fermentation
B. Hop bits and yeast sludge caused some extra reaction in bottles?
C. Some other weird thing I am not considering.

Thanks and sorry for the long response! Also, beer tastes great after I lose 2/3 of it to the explosion, so I don't think funky bacteria caused it.

The highlighted items may be the cause. You don't have bottle bombs, you have beer volcanoes because of the hop/yeast that is still suspended. These suspended particles form nucleation points for the CO2 to come out and that makes your beer want to foam up. Give them a few more days (like 14 more) and try one again.
 
I once dry hopped part of a batch with some W-A-Y outdated hops that had apparently begun to spoil, ergo, bacteria in the beer, ergo, bottle bombs. The non-dry-hopped part of the batch was fine.
 
I think I figured it out. I measured my priming sugar based on 5 gallons, but with the 2oz of leaf hops soaking up almost a gallon (or at least trapping that much in the un-siphonable sludge) I guess I over primed.

That being said, I calculated that much sugar in 4 gallons of beer and its only about 3.5 vols, so Im not truly sure why I got the bombs. Only some seem to be explosive, after putting it in the lager chamber @ about 36-38 degrees they seem to have calmed down.
 
I think I figured it out. I measured my priming sugar based on 5 gallons, but with the 2oz of leaf hops soaking up almost a gallon (or at least trapping that much in the un-siphonable sludge) I guess I over primed.

That being said, I calculated that much sugar in 4 gallons of beer and its only about 3.5 vols, so Im not truly sure why I got the bombs. Only some seem to be explosive, after putting it in the lager chamber @ about 36-38 degrees they seem to have calmed down.

Some bottles exploding and not others points to one of two things: an infection, or uneven distribution of simple sugars.

How much did you stir after you added the priming sugar?
 
It's only been 6 days. My money would be on the CO2 not being fully absorbed into solution yet combined with a slight over-prime. I'd just give it another week at room temps, then 24+ hours in the fridge before deciding on anything being wrong.
 
I didnt stir at all. I pour the sugar solution in the bucket first, the rack beer from carboy to bucket. Ive done about 6 batches this way and havent had any issues. Should I be stirring?

Anybody want to swing by on 4th of july and enjoy my american flag capped FPA (Firework Pale Ale)? Lol
 
It's only been 6 days. My money would be on the CO2 not being fully absorbed into solution yet combined with a slight over-prime. I'd just give it another week at room temps, then 24+ hours in the fridge before deciding on anything being wrong.

That's not how it works with bottle conditioning. The CO2 is created in solution, there is no need for it to absorb into solution because it's already there. Some of the CO2 in solution will come out of solution, and pressurize the headspace. The warmer the beer, the more CO2 will come out of solution, and the higher the headspace pressure. But the fraction of the total CO2 in the headspace is small compared to what is in the beer.

Let's do an example: 1 volume of CO2 is defined as 1.9768 g/L. OP carbed to 3.5 volumes, so the beer contains nominally 3.5 * 1.9768 = 6.92 g/L of CO2. 12 oz of beer is 0.355 L, so the beer contains 0.355 * 6.92 = 2.456 g of CO2. At 70˚F 3.5 volumes of carb will have a headspace pressure of 44.8 psig or 44.8 + 14.7 = 59.5 psia. 70˚F is 21.11˚C, so the CO2 density in the headspace is:
1.9768 * (59.5 / 14.7) * (273.15 / (273.15 + 21.11)) = 7.42 g/L
59.5 / 14.7 is the pressure correction
273.15 / (273.15 + 2.11) is the temperature correction​
Now the headspace in a 12 oz bottle is about 0.024 L (0.8 fl oz), so the headspace contains 0.024 * 7.42 = 0.176 g. So, the beer contains 2.456 / 0.176 = 14 times as much CO2 as the headspace.

What happens when you chill the beer to 37˚F (2.78˚C)? Well the pressure in the headspace drops to 21.0 psig = 35.7 psia. The density of CO2 in the headspace then becomes:
1.9768 * (35.7 / 14.7) * (273.15 / (273.15 + 2.78)) = 4.75 g/L​
and now the headspace contains 0.024 L * 4.75 g/L = 0.114 g of CO2. Thus in going from 70˚F to 37˚F, the beer only absorbs an additional 0.176 g - 0.114 g = 0.062 g of CO2, in addition to the 2.456 g that was already in the beer.

Brew on :mug:
 
In addition to all the other good points that have been made that explain your scenario, I have an additional one.
The temperature of the beer during fermentation and then at bottling time plays a role in the carbonation, especially if you cold crash.
Colder beer has more residual CO2 in solution and then adding priming sugar on top of that can cause issues.
I had a situation a couple years ago where I lost about 17 bottles in 2 different batches.

Just wanted to throw that out there.
 
In addition to all the other good points that have been made that explain your scenario, I have an additional one.
The temperature of the beer during fermentation and then at bottling time plays a role in the carbonation, especially if you cold crash.
Colder beer has more residual CO2 in solution and then adding priming sugar on top of that can cause issues.
I had a situation a couple years ago where I lost about 17 bottles in 2 different batches.

Just wanted to throw that out there.

I did a full analysis of this a few months back (find it here.) The net is you should use the highest fermentation temp the beer has seen, rather than the cold crash temp, in a priming sugar calculator. If you put in the cold crash temp, you will under carbonate your beer.

Brew on :mug:
 
I did a full analysis of this a few months back (find it here.) The net is you should use the highest fermentation temp the beer has seen, rather than the cold crash temp, in a priming sugar calculator. If you put in the cold crash temp, you will under carbonate your beer.

Brew on :mug:

Yes.
Except if you bottle right after the cold crash (like I did) then you will over carb the beer (like I did)
 
Yes.
Except if you bottle right after the cold crash (like I did) then you will over carb the beer (like I did)
No, apparently you don't understand the analysis I linked in my previous post. The sooner you carb after cold crash, the more under carbed you will be, if you put the cold crash temperature in the priming calculator. You only over carb (and at most by less than 0.1 volume) if you cold crash for a "long" time (long enough for the CO2 in the headspace to get close to equilibrium with the beer at the new temperature.)

If you think I'm incorrect, please provide a detailed, physics based, explanation of where I went wrong. If I have made a mistake, I will apologize, and thank you for teaching me something.

Brew on :mug:
 
No, apparently you don't understand the analysis I linked in my previous post. The sooner you carb after cold crash, the more under carbed you will be, if you put the cold crash temperature in the priming calculator. You only over carb (and at most by less than 0.1 volume) if you cold crash for a "long" time (long enough for the CO2 in the headspace to get close to equilibrium with the beer at the new temperature.)

If you think I'm incorrect, please provide a detailed, physics based, explanation of where I went wrong. If I have made a mistake, I will apologize, and thank you for teaching me something.

Brew on :mug:

I was in total agreement with you.
The link provided a very concise explanation of sound scientific principles.

I should have explained more in my response. I cold crashed both beers during winter months for almost 10 days.
Then added priming sugar according to Beersmith, which had a default temp of 65 in the program.
I bottled more at 40 degrees.

The only thing I would disagree with now is that I think that the resulting beers were off by more than the 0.1 volumes that you mentioned.
As those beers bottle conditioned and got warmed to around 65 and 70 degrees, they started popping like crazy. I stuck them back outside wrapped in a blanket to prevent freezing and managed to salvage a bunch of them.
I still opened every bottle outside though and everyone was a gusher.

You have provided an experiment for me though. I am going to use Brewers Friend calculator and plug in varying temps to see how the amount of dextrose required varies accordingly.
EDIT: Research on Brewers Friend
5.0 gal on beer at a required 2.0 volumes of CO2
70 degrees: 0.83 volumes of residual CO2 in the beer from fermentation (3.4oz of dextrose required at bottling time)
45 degrees: 1.32 volumes of residual (2.0 oz of dextrose needed at bottling time)

So in my double batch gusher scenario, I had 0.49 more volumes in my beer than I intended. I usually shoot for 2.5 volumes in my beer and likely ended up with closer to 3.0
I added 1.7 times more priming sugar than i was supposed to.
 
The amount of CO2 left in the beer from fermentation will be a function of the fermentation temperature not the cold crash temperature, as Doug is trying to explain.

The co2 level in solution will reach equilibrium during the fermentation phase, and because no new co2 is being produced during the cold crash, the only thing the cold crash can do is PRESERVE the amount of co2 from the fermentation. The residual co2 in solution can only be as high as it was when it reached equilibrium at the ambient temperature and pressure during the fermentation.

If, however, you cold crashed early while fermentation was still active, this would certainly be an issue.
 
EDIT: Research on Brewers Friend
5.0 gal on beer at a required 2.0 volumes of CO2
70 degrees: 0.83 volumes of residual CO2 in the beer from fermentation (3.4oz of dextrose required at bottling time)
45 degrees: 1.32 volumes of residual (2.0 oz of dextrose needed at bottling time)

The only thing this illustrates is that you did not understand Doug's post and that the calculator thinks you fermented at 45F or 70F. The temperature you input into brewers friend is meant to be the fermentation temperature, not the bottling temperature.

Quote from brewer's friend, a little further down the page.

"* Temperature of Beer used for computing dissolved CO2:
The beer you are about to package already contains some CO2 since it is a naturally occurring byproduct of fermentation. The amount is temperature dependent. The temperature to enter is usually the fermentation temperature of the beer, but might also be the current temperature of the beer. If the fermentation temperature and the current beer temperature are the same life is simple.

However, if the beer was cold crashed, or put through a diacetyl rest, or the temperature changed for some other reason... you will need to use your judgment to decide which temperature is most representative. During cold crashing, some of the CO2 in the head space will go back into the beer. If you cold crashed for a very long time this may represent a significant increase in dissolved CO2. There is a lot of online debate about this and the internet is thin on concrete answers backed by research. We are open to improving the calculator so please let us know of any sources that clarify this point."

aka "we don't know which temperature to use because we haven't done our research properly" no offense.

There is no debate. Doug is 100% correct and his math is not wrong. That's the nice thing about physics and math, they are true no matter how much anecdotal evidence is thrown at them.

How about this simulated Q&A session:

Q. Where does the CO2 in solution come from?
A. Fermentation

Q. What decides the maximum amount of CO2 that could possibly be in solution?
A. It is the rate of CO2 production, the temperature of fermentation, the CO2 partial pressure of the fermentation vessel

Q. Doesn't the CO2 in the headspace get reabsorbed during a cold crash and raise the CO2 in solution?
A. See Doug's analysis. In short, yes but it's not enough to make a difference

Q. So what decides how much CO2 is in solution at bottling after a cold crash?
A. The temperature and pressure during fermentation

Q. So what caused my bottle bombs?
A. probably bottling too early.
 
Thanks.
I figured that i must be missing something on my phone app, so I went back and checked out the link on my computer.

When I clicked on Doug's research link on my phone app, all it showed me was the data that was copied and pasted and not the multitude of calculations and data that he provided.
When i did the same on the computer, I got to see what I was missing.

Sorry for any confusion that I created. I just knew that I had a situation where I lost a bunch of bottles and attributed it to the fact that I cold crashed and ended up overpriming my beers.

I know for a fact that I did not bottle prior to fermentation being done though. Looking back at my notes, I took 5 separate hydrometer readings (calibrated in distilled water at 70 degrees) of beer samples (all taken at 70 degrees as well) over a span of 11 days.
*even covered samples in the cylinder with saran wrap to prevent any evaporation and error until it was time to take reading*
I got final gravity of 1.010 all 5 samples (OG was 1.056)

I received a refractometer 2 days prior to bottling and checked the reading with that and determined after correction that my reading was 1.011.

The beer was done fermenting.

I still lost 17 bottles of beer to explosions and another 72 to gushers.
The only thing that I had differently (and have not done since) was to cold crash down into the 30s and 40s and then bottle immediately.

Now I cold crash and then warm it up to 60/70 before bottling.
 

Latest posts

Back
Top