Brewed an Oatmeal Stout and it has been in bottles for about 4 weeks now and still the bottles haven't carbonated. Tried the first bottle after 2 weeks and it was very flat. Now I just opened one after another 2 weeks and still no head at all but it doesn't taste as flat as before. Anything I can do? Unfortunately I do not have a kegging system. It tastes awesome just a little flat which is disappointing as this was my first partial mash and the whole process was awesome except for the final outcome.

Recipe and Notes on the batch here

Thanks, ~ Tom

  • how much priming sugar did you use?
    – Brian
    Commented Mar 20, 2011 at 1:33
  • 2
    good call, 4 oz. of corn sugar based on the calculator from tasty brew here: tastybrew.com/calculators/priming.html and the fact that whenever I use a full 5 ounces I seem to be overcarbonated and get a 'head volcano' when I open a bottle.
    – tomcocca
    Commented Mar 20, 2011 at 1:41
  • Great read / tips thank you, My brew is not carbonating. So I'll move it from basement 65f Up two stories 75f. Give it 5to7 days, and let you know how it works. Thx
    – user12218
    Commented May 20, 2015 at 22:08

6 Answers 6


If you are sure your primed the bottles then they should most definitely carbonate. It could be a temperature issue creating sluggish yeast. What temperature are your bottles at? Get them to 70F or better and they'll start carbonating. Put one on top of your water heater for a few days and see what happens.

EDIT: You know another great place to warm bottles is on top of the fridge. The fridge generates a fair amount of heat in the back, and it generally is escaping from the top. I have put a case of bottles on top of the fridge before and trapped the escaping warmth with a towel or small blanket. Alot of fridges have those two hard to get to cabinets above the fridge. I 'll put a case on top and them use the doors to hold the towel to make a tent over the bottles. This helps trap that warm air around the case of beer. Of course if you have a super nice kitchen and a wife this might not fly very well.

  • Bottles were probably at like 62ish degrees. Shook them up a touch and moved them to warmer area, in front of one of my radiators. I'll give it a week and see what happens.
    – tomcocca
    Commented Mar 20, 2011 at 17:29
  • 3
    62 is way to cold. You'll be all set in another couple weeks. I'd rotate the case of beers to be sure they are all getting evenly warmed...if they are in boxed cases.
    – brewchez
    Commented Mar 21, 2011 at 12:27
  • As an aside - more and more refrigerators have their cooling coils in the bottom, not in the back, making the above warmer completely ineffective for any sort of yeast-related activity - beer or bread - which is a bummer.
    – Herb
    Commented Mar 21, 2011 at 18:53
  • As a followup, its been about 8 weeks, the beer has carbonated more since I got the temp up some. Only problem is that when I pour, the head goes away very quickly. I do see something that looks like oil on the top of the beer in the glass. I know for sure its a clean glass. I am wondering if this is hop oils? I think this is what is killing the head on the beer. Beer still tastes good anyway. Thanks guys.
    – tomcocca
    Commented Apr 18, 2011 at 1:25

I had the same issue with an oatmeal stout. I also used 4oz of sugar. It ended up okay in the end though after turning the bottles upside down, gently rousing the yeast and raising the temperature. Not familiar with that yeast strain, but I'd imagine 64 is too low for the yeast to be happy. Raise the temp, swirl the bottles upside down and give it a couple more weeks.

  • 1
    If this doesn't work your yeast is likely dead. You're going to have to uncap all the bottles and add a couple gains of neutral dry yeast to each bottle.
    – jbondeson
    Commented Mar 20, 2011 at 14:38
  • I'll give this a shot and see what happens. @jbondeson would adding Coopers Carbonation drops help at all or just getting more yeast? I think I have a packet of Muntun's Dry Ale yeast floating around, how much would you advise to each bottle if the temperature change doesn't fix it?
    – tomcocca
    Commented Mar 20, 2011 at 17:30
  • @tomcocca - adding a carbonation drop into it will likely result in a beer geyser (that's the first thing I tried when it happened to me). For dry yeast you really need only a couple of grains, with your FG and bottling sugar there should be plenty to see them multiply and carb it up.
    – jbondeson
    Commented Mar 21, 2011 at 2:52

IMPO I wouldn't do anything. I have have some batches that have taken 5 weeks to carbonate. You mentioned that the last time you tried them they didn't taste as flat as the first time, which would indicate that they are carbing up, just slowly. Good call on rotating them and putting at a little higher temp. This should get them going, just have patience. I would not under any circumstance add more sugar. It sounds like you primed them right and if you add more sugars you could end up with bombs.


A last resort is to use dry ice as you serve it. Cools and carbonates at the same time. Used to rescue flat soda this way (poor chemistry students, you know ;-)) and I have used it on hard cider to improve the carbonation while serving. Dry ice can be found in most large chain supermarkets these days.

  • Interesting, what would this do for the head of the beer?
    – tomcocca
    Commented Mar 20, 2011 at 20:05
  • Never tried it in beer, but suspect that there would be pretty strong foaming as the gas (carbon dioxide) is released VERY vigorously. May end up with too much head with beer.
    – drj
    Commented Mar 24, 2011 at 21:22

I've had a similar issue with a brew. I just shook the crap out of it and 2 weeks later it was carbonated.

The better solution would be to add some more priming sugar though.


A heads up for future use :) When doing natural carbonation, storages temperature is extremely important. That is, the amount of sugar needed to achieve adequate carbonation depend heavily on the temperature you plan to store your beer at..

Assuming you're aiming for an average carbonation level of 2.4 vol co2 AND you plan to store your beer at room temp (i.e. 72F / 22C) you'll need: 0,22 oz/L or 6,4 g/L.

If you're aiming for the same carbonation-level but storing your beer at around 50F / 10C (which I often am) you'll need 0,17/L oz or 4,8 g/L..

  • So you need more sugar when it's hotter? For me that seems counter intuitive... But really good to know as I live and brew in a warm climate!
    – user7964
    Commented Jul 9, 2014 at 6:58

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