Marginal PSI rise in spund/condition mode, a micro measure of activity after SG changes negligible?

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May 28, 2018
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As a preface, I've been carbonating with spunding in kegs for many batches. Fair percent of my brews are cold lagers, so am accustom to longer conditioning times, both before and after crashing. This is about before crashing, at cellar temps, ales and lagers.

When I rack the kegs off the fermentor, I generally want to have .004-8 gravity left to go. Usually most of active process is done in less than a week, keg nicely carbonated. Temperatures with ales, cellar temp, lagers controlled D rest , ramps and the like.

Many times, even after a week a cellar temp, the PSI will creep up, maybe as little as a half a unit per day, for several days. From what I can see, the change in gravity is undetectable with a standard hydrometer, even though something is obviously still working to raise PSI in keg.

My contention, or hypothesis is that there is still potential for some yeast activity to "clean up" brews for several days to a week after most would assume was time to cold crash.

Anyway, not looking for an argument here, just what I've worked out for myself after many batches. If anything to add or questions, would be interesting.

To be clear, (just like my clean crisp beers), the PSI raise is not result of infection or temperature fluctuation.

So to finish, if one has sufficiently long patience or pipeline, it might be good to try longer pre crash conditioning on some beers, if looking for the clean clear sort. One way to measure the progress is with PSI in kegs.

As a side note, I do not leave gauges on kegs, just check once a day or so, there would be potential for leakage if gauge left on, and the pressure changes are small, so we don't want that.