Capping Fermentor, CO2 production vs. SG to determine the end of fermentation

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I have recently begun fermenting in kegs. I start with a blowoff tube and when things slow down, after seven days or more, I cap my kegs with a spunding valve set at 14 PSI. Then, after 10+ days I completely cap it. At that point, I periodically release CO2 to bring the pressure below 15 PSI. As long as significant CO2 is being produced, I let it ferment. Eventually, after 14 days or so, I cold crash.

I find I am fermenting longer than when I checked FG and the beers don't have off flavors.

Is this a better way to measure when fermentation is finished than FG?
 
I find I am fermenting longer than when I checked FG and the beers don't have off flavors.

Is this a better way to measure when fermentation is finished than FG?

You really aren't fermenting longer, it only takes 3-4 days for a moderate OG beer to complete fermentation but the beer will have a large amount of CO2 dissolved in it and it will keep coming out of solution for quite some time. The hydrometer is the only real way to determine when your beer has reached Final Gravity.

Since you are kegging your beer, you probably don't need to use the hydrometer like people who bottle do. When bottling one needs to be sure the fermentation hasn't stalled out or you risk bottle bombs. With the keg you can simply release some pressure if it gets too high.
 
You really aren't fermenting longer, it only takes 3-4 days for a moderate OG beer to complete fermentation but the beer will have a large amount of CO2 dissolved in it and it will keep coming out of solution for quite some time. The hydrometer is the only real way to determine when your beer has reached Final Gravity.

Since you are kegging your beer, you probably don't need to use the hydrometer like people who bottle do. When bottling one needs to be sure the fermentation hasn't stalled out or you risk bottle bombs. With the keg you can simply release some pressure if it gets too high.

If the temperature is constant and the pressure is increasing isn't additional CO2 being produced?
 
There is probably some complicated formula involving temperature and pressure that determines when CO2 goes in and out of solution. Anyone?
 
There is probably some complicated formula involving temperature and pressure that determines when CO2 goes in and out of solution. Anyone?
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You can kind of see the effects of temp/pressure in this chart. Once you cold crash the yeast aren't going to be producing much, if any, CO2 anyways
 
If temp is constant, then I would say yes increased pressure is caused by increased gas production.

If that is true, then the yeast is still working and perhaps this is a much more accurate measure of fermentation.
 
What sort of beer are you fermenting? Lagers? What gravity?
An ale at typical gravities (say, 1.050 to 1.060) should typically done in about 4 to 5 days. If it's taking 10 days then there's a ferment issue. I also ferment in kegs (only a recent change), attaching a spunding valve when the ferment slows down. This is normally at about day 3. Lagers are a different beast.
 
What sort of beer are you fermenting? Lagers? What gravity?
An ale at typical gravities (say, 1.050 to 1.060) should typically done in about 4 to 5 days. If it's taking 10 days then there's a ferment issue. I also ferment in kegs (only a recent change), attaching a spunding valve when the ferment slows down. This is normally at about day 3. Lagers are a different beast.

I do many styles at different gravities, ales and lagers. I was trying to generalize to put forth the idea for review.

But, I have been surprised at how long CO2 seems to continue to be produced past what I thought was FG.
 
If the temperature is constant and the pressure is increasing isn't additional CO2 being produced?

No, not necessarily.
It could be that the increased preassure is just CO2 releasing from the solution.

If you release the preassure of the keg, ofcourse it will rise again from CO2 in the solution without any additional CO2 being produced.
 
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