Back to Shopping at

Exploding beer!

I made an all grain brew (small batch) about 8 weeks ago, it was a maple porter. The recipe did not come from Northern Brewer.

It required me to add maple syrup to the fermenter (maybe to the wort as well, I honestly don’t remember). I was also instructed to add maple syrup to the beer prior to bottling, instead of using priming sugar.

I bottled after 2 weeks in the fermenter, and then they have been in bottles ever since. After about 2.5 weeks, I had one bottle explode (devastating when you only have 1 gallon total). After about 4 total weeks in bottles, I drank one. I was using leftover Grolsch bottles, and the intense pressure inside the bottle blew the cap right off the bottle when I opened it, and then I had a foam fountain in my kitchen! Yesterday I found another bottle shattered in the basement.

I have figured out a method to still get about 99% of the beer into a glass and drinkable, but I am curious why this may have happened. Did I leave it in the bottle too long before moving to a cold fridge, thus allowing any yeast to still go to town on the sugars? Could it be that my maple syrup may have had too much sugar, thus when I added it as a priming sugar, it was high and created more pressure? This has never happened before, losing 2 bottles and having all the others create beer fountains, and if I did something wrong I obviously want to make sure to never repeat it. Any ideas?

Oof… two things…

  1. 2 weeks is kinda short for a fermentation period. My guess is the original sugar didn’t ferment out all the way before you primed and bottled. Hydrometer readings are essential to make sure you’re at final gravity before bottling.

  2. Did you use a priming calculator for determining how much syrup to add before bottling? If you added too much, that also could cause bottle bombs.

Never count on “moving to a cold fridge” to stop bottle conditioning… a properly bottled beer can sit for months, and not overcarbonate.

Don’t use maple syrup the sugar content is not all the same and your not gaining any flavor. I agree 2 weeks is wat to short. 1 month for a maple Porter

yea I just followed the recipe instructions, they said 2 weeks in the fermenter then 2 more in a bottle. They also told me to use the maple syrup for priming. I had never used maple sugar, so I just followed their instructions to a “T”. After this, I don’t know if I should just avoid their recipes in the future, or just shy away from maple related items. 2 out of 8 bottles explode, the other 6 I get about 90% yield out of if I use a few pouring tricks. So I’m only getting about 68% yield out of my brew, pretty annoying. Below is the link to the instructions

The problem with following directions to a “t” is that they are written to a “t”. If they assume you have exactly 1gal to bottle and tell you to use the 3 TBS of syrup to prime you’ll have exploding bottles if you only have 3/4gal to bottle.

Dang… those instructions are kind of problematic. The recipes might be okay, but the technique leaves a lot to be desired.

I used the NB priming sugar calculator (Homebrew Priming Sugar Calculator). It calculates for maple syrup, in a porter, at 70 degrees, .07 cups of maple syrup. That’s equivalent to 1.12 tablespoons. The Brooklyn Brew Shop recommended 3 tablespoons… holy crap, that’s dangerously bad advice.

1 Like

If they are flip top groulsh bottles try burp them a few times to relieve the pressure you could probably salvage them. I’ve done it With limited success

haha well there you go! they had me add way too much syrup it looks like.

There is no real way to burp these bottles, the instant the top is open, a fountain of beer erupts. The first bottle I opened was on my kitchen counter, and the foam reached the ceiling! I put the bottle in the sink just to try to avoid more mess, and when the dust had settled, I had probably 20% of the bottle remaining. The foam just takes off and keeps coming. Also… the cap gets blown off of the bottle. This means the little metal retaining clip goes flying too! Can’t burp a bottle when the cap detaches from the bottle and flies away! It was annoying, but humorous

That would be a good video to watch, from an unknowing victim!! Not wishing you any bad joo joo… I had some too in my beginning days… Foam monsters!! Sneezles61

This has been bugging me, (I am in quality assurance for my day job), and the first hint is that the instructions mention honey instead of syrup (copy/paste error, likely). Backing into appropriate carbonation levels, the only thing that makes sense would be three tablespoons of DME. They totally borked their instructions, mixing up measurements and priming ingredients. Original poster, I’d be tempted to contact them and point out the mistake, and their bad instructions. I figure they at least owe you a replacement kit.

If you follow the instruction for a recipy just change it a bit. If the recipy does say 4 weeks. For example just add 2 weeks. More. The yeast and sugars do seem to like it. And on the end beter beer

I’m going to repeat a song I’ve sung before, so I’ll start by apologizing for the repetition.
Bottle bombs are not just messy; they’re dangerous. I required sutures after my first encounter and was fortunate they were on my arm, not my eyes.

Before even considering bottling, check your gravity. Then, three days later check it again. If the specific gravity is the same over two or three readings, it’s generally safe to bottle - if the readings are very close to the expected final gravity. It’s possible that multiple identical readings could be due to a stuck fermentation; that’s why it’s useful to refer to an expected final gravity. Don’t rely on only the expected final gravity and don’t even think about depending on a suggested fermentation period - I believed the instructions and got bitten for my gullibility.


Early on I tried all sorts of alternatives for priming. Honey, maple syrup, DME. None worked as consistently as corn sugar (glucose). Now I use table sugar (sucrose) in about the same amount and it works well also.

This is very handy for priming Homebrew Priming Sugar Calculator

@old_dawg has some solid advise. Those bottles are a disaster waiting to happen. I would store them in a solid container just in case and if you decide to open them do it carefully. Sounds like overkill but safety glasses and gloves might be good. I have been lucky and never had a bottle explosion but have had complete foam outs. Now I prime kegs and they can stand tremendous pressure plus you can pull the pressure release ring to let off some.


Its just a wonder I’ve never had some bottle grenades, crack the top off, and it hits the ceiling, foam all over the place… I will consider myself lucky… The best advice has been given… check your gravity, and check again… If you are too lazy to do this… you’re flirting with disaster!! Sneezles61

The gravity all checked out. My OG was a little off, but the FG was really close to where it should have been. So I really tried to have it work out, but alas it was not meant to be. I have been keeping the beers inside of a rarely-used shower stall. That way, if/when they explode, they are somewhat contained and in a place that is easy to clean (detachable shower head, drain in the floor… cleanup is a breeze). I was just bummed because I lost so much of my product, and that I lost 2 grolsch bottles. Not the end of the world, and so far no injuries.

Next time, I will use a better calculator for how much priming sugar to use. Question: if the online calculator (on Northern Brewer) says to use 3.5 ounces, but my Northern Brewer recipe kit came with 5 ounces of sugar… should I trust the calculator, or should I trust their recipe? Is the 5 ounces just the standard for 5 gallon kits, and you are supposed to figure out exactly how much of that to use?

Using too much maple syrup for priming is most likely all or in part of the gusher problem. It is also possible that the fermentation had not finished. The instructions don’t mention the type of yeast included with the ingredients.

We really don’t know what the final gravity will be, especially using an unknown yeast, with an all grain or an all extract recipe. Too many variables. The attenuation figures offered by the yeast manufacturers are for comparison of their yeasts by fermenting a standard wort at one fermentation temperature for ale yeasts and a two temperature fermentation for lager yeasts.

Whether or not the yeast will stay in suspension at a stable temperature has a large effect on whether the yeast will continue working until the real final gravity is reached.

Trust the carbonation calculators more than recipe instructions. It is a matter of cost savings to include a standard pack of priming sugar with a kit. Most likely all of these packs are at least 5 ounces, but could be more.


Yup, the standard is a 5oz pack of corn sugar for bottling. The one-size-fits-all approach works about as well with priming sugar as it does with T-shirts.

When I started out, I just dumped the whole thing in. It absolutely lead to overcarbed beers, but not really gushers. The one batch of super foamers I had was (in hindsight) resultant from bottling after a stuck fermentation. Eventually, rather than buying and wasting up to half a bag of corn sugar, I just started weighing table sugar, per the calculator, and was much happier with the results.

I used to be in the camp, more is better! Nope… And that is to both, priming AND more barley for a bigger brew! I don’t like gushers, and I enjoy making it past 2 brews! Sneezles61

Back to Shopping at