I don't get bottle conditioning

My bottling procedure has been the same for every brew, but I've recently had two over-carbonated batches that I just can't figure out. Strangely, they were both hoppy beers. I always weigh my priming sugar by grams, and I adjust linearly if I'm bottling more or less than 5 gallons. My rate is 108g dextrose per 5 gallons.

I'm pretty sure these two batches had fermented out completely because they both went about 4 weeks from brewing to bottling. Also, I noticed that it took some time for them to become over carbonated. For a couple months they were great, and then I kept having problems with pouring overly heady beers. I thought I was just doing a terrible pour but then I noticed the beer was much drier-tasting with the extra carb.

I've seen some links to John Palmer's nomograph for determining priming levels, but I don't quite understand why it works. I understand that a liquid can hold more CO2 when it's colder, but I don't understand why you have to use different amounts of priming sugar at different temps. In my mind, X amount of priming sugar produces Y amount of CO2, no matter what temp your beer is. Serve it colder, and more of the CO2 will remain in your beer as you drink it.

Anybody care to explain this stuff?

Is there a possibility of an infection in the bottles?. Maybe the hop flavor is masking the infection. Just a thought.

I guess it's possible, but I don't think it's likely. With both batches, every single beer is affected equally. At the time of bottling, the SG of both beers was constant from the last SG reading. None of the bottles has any kind of residue at the surface of the liquid. These weren't consecutive batches, and I've used the same equipment my entire brewing career, with the same sanitation techniques, etc.

kanzimonson said:

These weren't consecutive batches, and I've used the same equipment my entire brewing career, with the same sanitation techniques, etc.

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Hmm, that's interesting. I'll have to think about it some more.

annasdadhockey said:

Is there a possibility of an infection in the bottles?. Maybe the hop flavor is masking the infection. Just a thought.

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A definite possibility. However, the temperature of the beer for priming calculations could still be an issue for you.

The reason you have to use certain amounts of sugar for bottling beers of certain temperatures is because the yeast will ferment the sugar you add and create a small amount of alcohol and the CO2 for carbonation. Remember, it's the temperature the beer was recently held at before bottling, not the temperature at which it will bottle condition.

If the beer was colder and therefore has more CO2 already in solution, you don't need to add as much sugar or the CO2 you're creating with the added sugar combined with the greater amount of CO2 already in the beer will give you more carbonation than you wanted.

When I bottled, I used to use this bottle priming calculator which allows you to just input the target CO2 volumes, gallons, and temperature.

I'm guessing a malfunction in your scale or your weighing procedure. It could also be mild infection, or a change in something else (bottling sugar from a different source?).

Edited to remove stupidity

I've had a similar issue. I'm pretty sure it isn't an infection. These aren't gushers, it's just that when I pour, I get a huge head and very fizzy beer. I've been careful about my priming sugar amounts. One thought I had is that I could be bottle conditioning too warm. I use an aquarium heater and water bath to condition at around 73F.

X amount of priming sugar produces Y amount of CO2, no matter what temp your beer is. Serve it colder, and more of the CO2 will remain in your beer as you drink it.

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Correct on both counts. The reason for using the nomograph is if you want to change the serving temperature without having seemingly flat or explosive beer.

menschmaschine said:

If the beer was colder and therefore has more CO2 already in solution, you don't need to add as much sugar or the CO2 you're creating with the added sugar combined with the greater amount of CO2 already in the beer will give you more carbonation than you wanted.

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So let's say the beer has been consistently at 60 degrees for fermentation and aging, and then the week I'm going to bottle, a warm front comes through, and the beer gets up to 70 degrees. Then the temp drops again, and the day I go to bottle, it's at 60 degrees. How do we account for a certain amount of CO2 in the beer?

When the temp increases, dissolved CO2 will escape. So do I calculate how much priming sugar to add based on the expected amount is already in solution at 70 degrees? We're assuming the beer is completely finished fermenting here, so if any CO2 is lost due to temp increase, it's not going to be recovered.

It just seems like it's really difficult to take all these things into account. Even though I don't have room for a kegerator, I'm thinking of getting a kegging system just so I don't have to deal with this nonsense anymore.

kanzimonson said:

So let's say the beer has been consistently at 60 degrees for fermentation and aging, and then the week I'm going to bottle, a warm front comes through, and the beer gets up to 70 degrees. Then the temp drops again, and the day I go to bottle, it's at 60 degrees. How do we account for a certain amount of CO2 in the beer?

When the temp increases, dissolved CO2 will escape. So do I calculate how much priming sugar to add based on the expected amount is already in solution at 70 degrees? We're assuming the beer is completely finished fermenting here, so if any CO2 is lost due to temp increase, it's not going to be recovered.

It just seems like it's really difficult to take all these things into account. Even though I don't have room for a kegerator, I'm thinking of getting a kegging system just so I don't have to deal with this nonsense anymore.

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This is one of the things in a lot of how-to homebrewing texts that I don't think is explained very well... least for those of us who try to achieve fairly precise carb levels. If the temperature is constant, it's easy. If you have a scenario like you describe, it's not so easy. For a lager with a diacetyl rest, it's even more difficult because even though CO2 is lost during the diacetyl rest, some is produced during lagering slowly by the yeast, but probably not enough to equate to the temperature of lagering.

I think if you understand the concept and that it can take a couple days for the beer/CO2 to reach equilibrium with the temperature, just use your best judgment on what temp to use for priming calculations. I have had occasions like you describe above where I've just gone somewhere in between with what temperature I use for priming calculations.

kanzimonson said:

I'm thinking of getting a kegging system just so I don't have to deal with this nonsense anymore.

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I would have to say this would be a wise idea. Its just so much easier... I made 6 batches before kegging, and once you switch you'll never look back!

Even the little things like only having to clean one thing every batch (the keg) instead of 50 (the bottles).

Also just check CL for a cheap fridge and for very little money you can just get some hoses and a picnic tap. You can certainly do it all for under 100 bucks if you work at it.