I brewed this Ale Oktoberfest beer and I thought everything went perfectly, but the bottles are flat (have tried 4 of them)

Some details:

  • 2 weeks in the primary
  • 1 week in secondary (5 gal carboy)
  • FG of 1.012
  • Priming solution: boiled & cooled solution of 5 oz. table sugar, mixed well into bottling bucket.

The bottles have sat for 3 weeks. They started out at over 70 but lately it has been cooler and they have been around 65 degrees.

I asked my homebrew shop and they said the problem is likely that I used table sugar instead of corn sugar. They said that disaccharides are harder to break down than straight glucose and maybe the yeast just couldn't do it.

However, looking online it seems lots of people use table sugar. This is my second batch, for my first batch I also used table sugar and it had perfect carbonation.

Here are all the possible problems that I can imagine:

  1. Too much yeast dropped out after secondary fermentation, so not enough was left in suspension to carbonate? (counterpoint: 3 weeks is not very long, if anything it's on the shorter side)
  2. Maybe they indeed had trouble with the disaccharide sugar (or maybe combination of 1 and 2)
  3. During my first batch I used vegan sugar from Whole Foods, my second batch I used Domino sugar
  4. I pitched the yeast a little warm (80-85 degrees). But the bottles have mostly been conditioning around 65. Maybe fermentation encouraged the growth of more yeast that preferred the warmer temp, and they don't like the cooler bottling temp.

Possible solutions:

  1. Bring bottles up to 70 degrees, wait longer
  2. Pour everything into bottling bucket, add CBC yeast and 5 oz. corn sugar solution, rebottle. (Problem with this: if the initial priming sugar was never fermented, would this create bottle bombs once healthy yeast is re-introduced? Would the priming sugar cause a measurable change in gravity, so that I could measure whether it fermented?)

Any other advice or thoughts?


I have a few more data points:

  • I tried more bottles: some have a tiny amount of fizz, others practically flat.
  • Immediately after bottling, 4 bottles went down to Virginia. When they were opened, they were all carbonated, with a head even.

I performed the following experiment:

  • I opened two 22 oz. bottles and added 1/4 tsp CBC yeast rehydrated in 1 1/2 tsp water
  • To one of these bottles I also added a solution of 3/4 tsp corn sugar

One week later, both were carbonated. The one with sugar more than the other, and maybe a tad overcarbonated but not by much.

I plan to add the same amount of yeast and 1/2 tsp corn sugar to the remaining bottles.

Thank you everyone for your help and suggestions. I'm not sure if there is one answer I can accept but I will read through them again and see.

Update #2

Here I was ready to add a yeast / sugar solution to each bottle. It has now been 7 weeks in the bottle and I last tried one maybe 2 weeks ago and was still pretty much flat.

I opened 7 bottles to re-yeast, all of them were carbonated. SMH.

  • In Brazil home-brewers mostly use table sugar within the proportion of 6g to 10g per liter (0.21oz to 0.35oz per 0.26 gallons). Your priming has about 7g per litre, that is fine. And if you boiled it for about 10 to 15min, you can reached a solution of inverted sugar syrup (even without the ideal low pH) that is more digestive by yeasts, so very quickly fermented. Near 5min of boiling, you just sanitized the solution of table sugar in water (it isn't an inverted sugar syrup, unless you reduced the pH). But, pure table sugar, or diluted, either inverted sugar syrup are good primings.
    – Luciano
    Sep 26, 2014 at 20:47
  • About your second item (solution), yes. You can measure the current gravity which could be higher than 1.012 if nothing was fermented. I estimate a gravity of 1,014 (a big guess) if your 5oz of table sugar wasn't fermented yet.
    – Luciano
    Sep 26, 2014 at 21:00
  • After week at 70 degrees, I chilled one in the fridge for 10 hours and it's still flat. 4 weeks total.
    – Ryan Silva
    Sep 27, 2014 at 21:19
  • 4 weeks !!! Wow ! Before assume your yeasts are dead, I would take one and add more priming (double), shake it, leave it in a secure place between 70F and 80F expecting it to explode (like inside a paper box). If after 7 days there aren't CO2, you have a great chance that our yeasts 'disappeared', maybe dead.
    – Luciano
    Sep 27, 2014 at 21:57
  • What about adding a few grains of CBC yeast to each bottle? I am also going to test gravity to try to see if the priming sugar has fermented.
    – Ryan Silva
    Sep 28, 2014 at 0:03

6 Answers 6


It's probably just too cool. I had lots of problems with carbonation when I left my bottles in my 65-70 degree basement. In fact, I had one batch where the bottles on the concrete floor did not carbonate but the ones sitting on top of those, off the floor, did carbonate. Eventually, I started putting them in the laundry room on a shelf above the dryer, where it's in the mid-eighties, and everything carbonated fine after that.

  • I also believe that is the current temperature. Mainly If the secondary fermentation was conditioned in low temperature (lets say, less than 50C), the yeasts can be dormant yet. Trying to elevate temperature near 80C can wake up them. I already read about shake the bottles, but I never did it.
    – Luciano
    Sep 26, 2014 at 21:16
  • Early on, I had a batch of big, hoppy beer that did not carbonate in the bottle. I tried putting them in a warmer spot and shaking the bottles. Some of them carbonated after that. I'm not exactly sure what oxidized beer tastes like, but I think that's what I tasted in those bottles. After that experience, I'd discourage shaking the bottles. (I'd also discourage trying to brew a big beer when you really don't know what you're doing yet!)
    – bughunter
    Sep 27, 2014 at 1:47

If you saw a beer head during the 2nd fermentation, you likely just let the beer get too cold. Ales tend to like 70F+ bottle fermenting conditions.

You can tell if your beer's yeast has died by the foam created when mixing in sugar. The reaction will always create alcohol and CO2. The reaction creates bubbles, which make the foam during fermentation. No bubbles = no yeast.

I doubt using table sugar is the problem. I have no idea why home-brew shops tend to universally disdain table sugar (except to up-sell you the expensive fermenting sugar). I have always used table sugar bought from Wal-mart and never experienced any problems.

In summary, you can either

  1. Keep the beers in a slightly warmer place.

  2. Make Lagers, which ferment a little colder.

  3. Your homebrew store will sell carbonation pills you can add to your bottles, but you'll have to open and reseal each of them to do this, your mileage may (and likely will) vary.

Edits to clarify questions about fermenation process, and better explain what to expect

  • What do you mean "saw a beer head during secondary"? I didn't see anything in the secondary except some yeast/sediment dropping out. Funny, the bag of corn sugar was like 60 cents, not like they are making much money on it.
    – Ryan Silva
    Sep 22, 2014 at 16:58
  • I call the foam that is created during the fermentation process the beer head. Its several inches of foam that floats on top of the beer. If you see that, you know that the yeast is still alive and turning the sugar into alcohol. Sep 22, 2014 at 17:29
  • There was plenty of that stuff during primary but not during secondary.
    – Ryan Silva
    Sep 22, 2014 at 17:51
  • Unless the beer is sealed, I believe if you do not have at least some foam, its a good indication your yeast has died. The foam indicates the yeast has created CO2, and it has bubbled through the beer. Sep 22, 2014 at 18:23
  • Is the yeast creating CO2 that late during secondary, even when the primary fermentables are used up? I know the yeast is still working on the complex molecules, but I thought that it wouldn't be releasing any CO2 anymore.
    – Ryan Silva
    Sep 22, 2014 at 18:33

Ehhhh, not having 50 points... Either way, I would HIGHLY recommend not opening up the bottles and adding anything, or taking anything else out. This is just asking for contamination or at least oxygenation. Warm the bottles up a bit should work. Or letting them sit longer works too.

Also, the yeast that is left in suspension when bottling is normally the strongest/most hyper yeasts from your brew. They should be fine with a little cooler temperatures, higher abv, etc.

  • I brought them up to the kitchen yesterday which has been 72ish. I think I'll leave them there for a week.
    – Ryan Silva
    Sep 22, 2014 at 22:23

You can always leave them longer at the lower temperature, or bring them up to 70ish. Which Yeast did you use specifically? Did you re-pitch yeast during bottling or it was warm for the initial pitch? 80-85 is pretty warm for Ale Yeasts. Wouldn't kill it, but might give off some flavors that aren't wanted. Prior to bottling were you still getting bubbles coming through the airlock?

I don't do much homebrewing since brewing professionally for 5+ years in the San Diego Craft Brewing Industry. But I still have plenty of knowledge of brewing in general.

  • I did not repitch any yeast during bottling, it was about 80-85 during the initial pitch. Flavor is very good right now. I got lots of bubbles during initial fermentation and lots of yeast and other byproducts which settled out. No bubbles to speak of during secondary though. I saved the yeast packet but forgot to take a picture, I'll try to find it. I did rehydrate it before pitching and it looked healthy.
    – Ryan Silva
    Sep 22, 2014 at 18:12

It might be that your beer is quite strong (you didn't mention the OG), and the yeast has bowed out. (what yeast did you use?)

What's the current reading on the brew?

I'd open up a couple of bottles, add a few crumbs of dehydrated yeast with a high alcohol tolerance (at this stage, using champagne yeast is quite ok, try it on a few bottles). Close it up again, put in a warm spot for a week, then cool it in the fridge for a day or two and open it to test.

I would not remove the beer from the bottles, it only oxidises the beer and introduces infections (plus extra work).

Also don't feed it more sugar unless you are sure it really needs it, exploding bottles are no fun.

FWIW, the only difference I can tell between cane sugar / beet sugar and brewing sugar is that cane or beet tastes most 'citrussi'.

EDIT: (to keep Stackexchange ettiquette happy):

Re: aerating, shaking the beer or water isn't all that effective, but if you get a fish tank air pump (with a little air filter, although I've used it w/o it and had no problems) and tie a weight to the 3mm tube that comes with it so it stays at the bottom, leaving this on over night starts the fermentation pretty quickly, probably because the wort gets moved around by the bubbles and the yeasts don't get stuck in areas they already munched empty in the initial time when the wort stays quite still. And don't bother with a buying fancy aeration stone thingy, just the tube as is works wonders enough.


  • I don't think it's particularly strong. I never took an OG reading but the FG is pretty close to the recipe spec so I'd assume OG was around 1.057. I bought some CBC yeast, I think I'll try that in a bottle or 2, thanks. I'll read the current gravity when I open another bottle.
    – Ryan Silva
    Sep 22, 2014 at 17:53
  • I'll need to try to find what yeast I used, I meant to take a photo of it but it should be saved somewhere. It was dry yeast which I rehydrated before pitching and it appeared active and healthy.
    – Ryan Silva
    Sep 22, 2014 at 18:15
  • Different yeasts have different alcohol tolerances. And the FG alone doesn't tell you how strong it is, you need to know the actual OG. It's real easy to end up with a 7/8% beer. Sep 22, 2014 at 19:23
  • So there's a chance I produced a beer which created too much alcohol for the particular yeast I used? How would I predict/avoid that in the future? This recipe is supposed to produce 5.7%.
    – Ryan Silva
    Sep 22, 2014 at 19:30
  • Well, that's variable, and if you mis-measured the amount of water or sugar (it happens), or if the yeast converted sugar more effectively in this case, then it's possible. And 5.7% is not that weak either. Another factor is how well the wort was aerated, yeasts need oxygen to make Sterol (which builds cell walls), which they then share with all their daughters in anaerobic fermentation. Sep 23, 2014 at 11:57

I have only ever used table sugar for priming my beer and never had an issue(40+ batches).

If you are struggling with temperatures I find that the hot water cupboard normally has a good temperature to help them carbonate. Put a few in there and see if you can get the temperature raised a bit. Another place would be on top of the fridge because they give off a little heat too.

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