25 psi is too much applied pressure on the keg for co2, you need to run that thing at about 15psig max.
I suspect that you did not get any foam for the first 3/4 of the keg because the beer was super cold in an ice bath of 120 feet of coil, by the time it got to the glass it was probably 33 or 34 degrees. When beer gets too cold it will suppress foam and give little head.
The keg was overcarbonated from the time it was first tapped by the evidence of the last quarter of the keg being all foam. You ran some through the coil and let it sit for a while, the temp dropped and suppressed the foam enough to pour.
The colder the beer gets the less co2 will absorb into it causing less foam and head (suppressing the foam), and if the temp continues to drop it will turn to solid and freeze.
Last edited by Dirtbag : 04-23-2008 at 08:54 PM.
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