Poured e bottles of brown ale 4weeks after bottling. Glass filled with foam with each bottle. Friend said he had the same issue with a pumpkin ale even a year after bottling.

What is causing this issue and will the beer taste ok if drank from bottle?

  • 1
    I would guess it's over-carbonated. How do you decide how much sugar to add at bottling? Good chart (nomograph) here from Palmer's book howtobrew.com/section1/chapter11-4.html
    – uSlackr
    May 27 '14 at 12:38
  • 4
    Don't drink from the the bottle. It will not improve the foaming issue and you'll lose the sense of flavor in the beer.
    – Denny Conn
    May 27 '14 at 14:46
  • 1
    Do the bottles foam over when opened prior to pouring? If not then you might just have very dirty glassware.
    – brewchez
    May 28 '14 at 11:15

There are 2 prominent answers to this:

1) Over carbonation. Can be a problem if the bottles start to explode. Solution when serving: Pour beer into a jug with a lid so that the foam is to the lid level and close lid. Repeat for another jug or two (depending on amount of beer that you want drink). Now pour from jug 1 (with the lid still on). The lid holds the foam back and you can get to your beer! Time will also allow the head to fall back, releasing the beer.

2) Infection. Bad news. Your beer tastes and smells different from what you planned (sour/acidic). Most people do not like sour beers. I would throw it out.

To not have over-carbonation, see @uSlackr's link or use carbonation drops (one per bottle for less than 500ml, 2 for less than 1000ml, etc. If you are using a bottling bucket, sugar or other methods, I can't help.

Infections: Clean and sanitize better. Remember the caps.


Over-carbonation is the most likely culprit. I've had this happen to a couple of batches, presumably as some combination of:

  1. not enough attenuation of the yeast to bring down the final gravity
  2. too much sugar added at bottling time

Initially i was brewing from recipes which included a standard amount of priming sugar. You can use a priming sugar calculator (like this one) to adjust the amount appropriately and avoid over-carbonation.

Once the bottled beer has matured, you should store it someplace cool to keep the yeast from continuing to produce carbonation.


Please forgive me for bumping an old thread and not providing a clear and concise answer. I have completed 4 pumpkin ales now with varying degrees of foam. Certainly refrigerating for 24 hours helps, which points to carbonation.

I did notice, however, that during my boil, the pumpkin proteins (or gunk?) that are in the wort seem to stick at the top and not get carried under with the rest of the boil. I was thinking that perhaps someone who has some experience with what exactly is in pumpkin (vegetables?) that might contribute to excessive foaming when it comes to pumpkin brews specifically.

Perhaps this should be it's own question, if so, please advise and I will delete/repost.

Yours, Jeff


I have a similar problem in one of my batches. Pouring the bottle resulted in nearly 100% foam and no beer. Since it only affected the one bottle out of 15 so far, I am certain this was due to an unclean bottle, even though I sanitize them all the same.. In addition to this, this one bottle also tasted different then all the others, even though it did not seem a "wrong" taste.


Others have mentioned over-carbonation. If that turns out to be the case (i.e. the beer is fine other than very carbonated) you can bleed off the excess.

  1. Refrigerate the beer for at least 24 hours.

  2. Using a bottle opener carefully open the cap just enough to allow the CO2 to begin escaping. You should be able to open it just enough to allow CO2 out without it foaming.

  3. Once the pressue has escaped fully remove the caps and re-cap with freshly sterilized caps

Try it with one bottle first. If bleeding the pressure once doesn't lower the carbonation enough then after step 2 you can use your capper to re-seal the bottle, put it back in the fridge for a few more hours, then bleed more pressure off again (sometimes it takes several rounds to lower it to where you want it). Recap with a new cap in the end to make sure you've got a good seal.

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