So my brother in law are in the midst of our 4th batch. Of our first batch ( a 5 gallon brew) probably 2 bottles turned out. These bottles were spectacular great carbonation, retention etc. The others flavors seemed ok but completely and totally flat. I noticed that the bottles that turned out where the smaller 12 ounce size.

3 weeks in fermenter before bottling and then 4 weeks before transferring bottles to refrigeration. We have removed the bottles and slowly warmed for another few weeks and tested again...still flat.

I personally suspect that we may have over primed and that instead of explosions we broke the seals on our caps. While inspecting the caps I noticed on the rubbery seal there is a tiny clear.clean spot along the edge where the rest of the cap is stained. I believe his could have been the point where the seal broke and was allowing gas to escape.

My plan moving forward is to remake the same batch and this time use swing top bottles to see if the results change.

Any insights you can share would be helpful.



  • You've stated that the beer is flat, but is there absolutely no hiss upon opening the bottles? If there is some hiss, then CO2 is being created, but not enough. If no hiss, then either your priming with a non-fermentable sugar (joke), or there's a leak. Seems unlikely that 50 bottles would all be pushed to leak without any exploding. Are you re-using caps? Any unusual chemistry after fermenting, something that might kill off the yeast entirely? Priming sugar will just sweeten the flat brew if there is no yeast left to eat it. How high is your Avg. Alcohol? Is it too high for Yeast? Commented Dec 2, 2014 at 22:59
  • If the swing top bottles are too pricey to buy 5 gallons worth at once, you might want to experiment with different primer sugar levels in the remaining capped bottles that you use (50%, 60%, 70%... of recommended, up to maybe 150%). Commented Dec 2, 2014 at 23:08
  • 2
    How are you priming? The whole batch or each bottle? What's the other types of bottle do you used besides the 12 ounces?
    – jards
    Commented Dec 2, 2014 at 23:22
  • If you are priming the whole batch, how well are you mixing the batch to disolve and distribute the sugars, before you start bottling? Commented Dec 3, 2014 at 0:52
  • - not reusing caps
    – Adam
    Commented Dec 4, 2014 at 19:36

2 Answers 2


Are the bottles that you are using screw tops? That might be the problem. Although some people have had success, others complained about leaks

How are you capping? Maybe you are causing damage by using too much force.

Test: place a balloon or condom over a bottle. If the item inflates, you have a leak. if it does not, open the bottle (after 2 weeks to allow for carbonation) and if the beer has no carbonation, then your priming is the problem.

  • All great comments thanks so much for the repsonses. The more I look in to this I believe we are dealing with loss of yeast through an extended primary fermentation and high ABV 9-11%. Think that even thought we are using the prescribed yeasts there is too little left at bottling and we should consider pitching yeast at bottling ( we have not tried this up tot his point)....thoughts???
    – Adam
    Commented Dec 4, 2014 at 19:42
  • Wing stlye capper. Pretty typical. We are applying with a single compression perhaps we should crimp it down twice.
    – Adam
    Commented Dec 4, 2014 at 19:46
  • 2
    Once is enough with the capper. I usually cap and then turn my bottles upside down. If the capper did not work I should hopefully see something immediately. Commented Dec 5, 2014 at 9:13
  • 1
    There should be more than enough yeast in suspension, unless you froze the beer or added chemicals. The ABV is not that high. I bottled my 10% DIPA with a measured amount of table sugar and it is perfect. Commented Dec 5, 2014 at 9:14
  • I think you can add 1g of rehidrated yeast to your bottling bucket. If I remember correctly you need 20 billion cells to carbonate a standard 18 liter batch. Commented Dec 5, 2014 at 9:16

It hard to diagnose this without pictures, numbers, etc...

Maybe you overprimed, maybe you didn't. Over priming with good caps = beer volcanos. And explosions. And a big mess. So maybe there is something wrong with your caps, bottles, or capper. Leaky caps should have held some gas, giving you random levels of carbonation. The only time I ever had a miss-cap, I could tell by looking at the outside of the bottle. The cap was obviously tilted. Weak/loose caps should be too easy to remove, but should still hold some pressure.

BUT, the most common cause of uneven / poor carbonation is not mixing the beer enough. Assuming you use 100-150g of sugar for 5 gallons (I use cane sugar, DME requires more I think), and you dissolve that in a few hundred ml of water, it'll be a few times more dense than your unfermented wort. (10% sugar is about 1.040, so 150g of sugar in 1.5 liters would be about wort's strength. Does anybody here add priming sugar with so much water?)

The priming sugar will sink like a rock.

My method is to stir the beer before I add he sugar, pour it in slowly (and quietly down the side of the racking cane) while the beer is still moving. Then stir some more. You'll raise the yeast up a little bit, so let it settle for another 30 minutes while you wash bottles.

Also - you don't need to wait a month to find out your results. 4 days will get enough carbonation to know if the beer is going to carbonate.

Please post numbers & pictures if you can.

  • 2
    You can also put the priming sugar syrup into the bottling bucket first, and then siphon the beer on top of it. No need for stirring. Commented Dec 3, 2014 at 14:44
  • Agreed with @TobiasPatton - I boil 1 cup of water, dissolve the sugar into it, put it into the bottom of the bottling bucket, then siphon the beer in on top of it. Shakes it all up and spreads it out, have never had a problem.
    – Haney
    Commented Dec 3, 2014 at 20:23
  • I read about this method of adding the priming sugar and this is what we have done so far. (adding to the bottling bucket and allowing the natural movement as the wort mixes to distribute)...
    – Adam
    Commented Dec 4, 2014 at 19:44
  • thanks so much for all the replies. I'm going to experiment with swing tops in tandem with the current bottles to test the caps scenario. I am also looking in to pitching yeast at bottling since we are working with such high abv brew.
    – Adam
    Commented Dec 4, 2014 at 19:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.