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Undercarbonation woes

I’ve been homebrewing for 2 years and made about 25 batches. Never had a spoiled batch - All of them turned out really good. When it came to priming, I followed a very simple procedure. I would just batch prime using a pre-measured 5 oz bag of corn sugar. It always worked, so, I never thought much about it. However, I realized that I was using too much sugar for most of the styles I was making.

Anyway, I got a digital scale and decided to accurately weigh my sugar in order to hit the correct C02 levels for the given style.

The very first batch that I did like this - WAY undercarbonated after 2 1/2 weeks.

Nothing has changed other than the amount of corn sugar I added. I batched primed NB’s RyePA with 4.1 oz of corn sugar. The room I bottle condition is around 64-68F. It’s the same room I have always stored my bottles in

What did I do wrong? Not enough sugar? Too cold for the storage? If it is too cold of storage why did the other bottles carb up good?


If you’re sure you did everything the same,
Could your new scale be off?
It takes a bit more table sugar than powdered sugar to get the same volume.
Just ideas.
Buy another pre bag and weigh it,
Maybe you get a bakers 5 oz in the pre bags

If I was to guess, I’d say you need a couple more weeks to condition. In my limited experience. A couple of weeks of bottle conditioning at 64-68 degrees might not be enough time to get good carbonation.

I’ve tried a couple of things. I gently inverted the bottles in order to agitate the yeast, I heard this can help. Also, I moved them to a warmer area in the house. Maybe that will improve the yeast appetite and improve my carbonation issue.

Also, I used to bottle with more sugar (5oz) and recently stepped down to (4 oz). Would that extra amount of sugar cause it to carb up quicker??

I guess I’ll just wait it out another couple weeks. If that doesn’t work, I might add some fresh yeast as a last resort.

Also, I checked my scale. I weighed a few items of various weights that had not been opened. They matched up with the stated weight on the packaging. So I think the scale should be okay.

My friend and I were never able to get good carbonation in bottles without following this procedure we came up with. Otherwise we had your results almost ever time even weeks later.

We mix 1/5th packet of T-58 dry yeast in a few tablespoons of filtered water and bring to room temp and throw that in the bottling bucket when halfway filled and mix well.

We add 5 oz corn sugar to 2 cups boiling water and add to bottling bucket before siphoning beer.

Store at room temp for 2-3 weeks. In 3 days your beer with have carbonation. In 1 week it will have been absorbed well in to the liquid and will be fully carbed. 2 weeks makes it perfect in my opinion and then chill for a few days before opening.

Otherwise alll we ever got was inconsistent carbonation. I can set my watch by this process and it works perfectly every time with no varying results.

Ok. So its been 4 1/2 weeks. There is some carbonation but it is weak. I did notice a few issues that might help with troubleshooting the problem

  1. The yeast sediment is not evenly deposited along the bottom of bottle. Its sort of patchy and the yeast is in fine clumps rather than a compact cake. The yeast was Wyeast 1056.

  2. The taste. It starts out bitter, like an IPA should, but finishes slightly sweet. I was expecting a dryer finish. Tastes hmmm… sugary…

Here’s my theory. When I checked my FG my attenuation was around 77%. The apparent attenuation is supposed to be 73-77%. Is it possible that my yeast was for lack of a better term “worn out” and wouldn’t carb because of this. I am thinking, as was stated, that there was not enough viable yeast to get the job done??? I have never run into this problem.

For a solution I am thinking of adding some fresh yeast to each bottle. I’m thinking I don’t need anymore sugar due to sweet aftertaste.

Has anybody done this? If so is it worth the time and what’s the best way to do it?

The yeast did run to their completion if you got those levels of attenuation. But then you put additional sugar into the mix which should wake them back up to carbonate. They’re not close to the alcohol tolerance limits so they should work.

Also in my experience it is hard to tell the difference between undercarbonated beers and ones that just don’t hold much head on them. If you don’t have much head then it is hard to tell how much carbonation is in them. Could that be the case for you?

If you have any carbonation at all, then at least some of the priming sugar has been consumed - you’ll need to add some more sugar along with the yeast if you want good carbonation because when you open the bottle to add the yeast, some of the existing CO2 is going to escape.

So if I do add sugar - How much?? Also what kind of dry yeast should I use?? I am thinking something neutral tasting. Maybe Nottingham or US-05.

There is some head retention on the beer. I realize saying that the beer has very low carbonation but has head retention doesn’t really make sense. But, when I drink it just tastes flat. Doesn’t make sense, but, thats the best way to describe it.

One thing I’d also consider, do you refrigerate the beer for a few days before popping it open? Cold temps can help a liquid absorb more CO2, which is why we keggers refrigerate the beer down to temp before turning on the CO2. I remember from my bottling days that the more time in the fridge, the better the beer seemed to hold up carbonation-wise.

Good luck.

IME, S-04, then US-05, then Nottingham. They’re all neutral but get increasingly lower in flocculation.

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