So I'm on my fourth batch kegging and I keep getting the same problem. Normally I purge with CO2, turn PSI to 20 for a day then turn it down to serving pressure, usually around 8, and leave it until it is carbed. Normally after a couple days it is perfectly carbed but then after another 5-7 days it starts to overcarb and gets some carbonic bite astringency that is really hard to get rid of. Does anyone else have this problem or a solution? Can it carb more than the pressure it is set at? Should I disconnect CO2 when not in use?
Bad gauge? While you don't say what style of beer you're serving, or the temperature, or the desired volumes of CO2, or ..., I can't imagine that 8 psi is going to cause the sort of overcarbing you're describing, even if the style doesn't call for it. Do you have a foaming issue, as well? If the gauge reads 8, but it's actually 16, then you'll have problems. FYI, 'serving pressure' is determined by the temperature and desired volumes of CO2 in the beer. The various charts will tell you what that should be. It's all about equilibrium. Serving pressure is then used to configure the dispensing system (line dimensions, etc)
2 IPA's, a smash and a wheat. Temp in my fridge is about 37. It pours almost like a stout, meaning that it pours a fairly big head and then after you stop pouring the beer "settles" with a bigger head.
Okay, 8 PSI @ 37F will settle at about 2.2 volumes of CO2, which for most styles is not overcarbonated. If you're getting too much foam, there are 2 main possibilities... 1) your beverage line is too short for the serving pressure, and therfore the beer is pouring too fast, and/or 2) the beer is getting warm on its way to the faucet. Do you have a tower, and is it (not) cooled?
On the foaming issue: 5 feet is pretty short. I generally go around 10 ft. on all my kegs. You get a slower pour, but you also don't get a glass with either no head at all or excessive foaming. One key to avoid foam is to not try and open the tap half-way to reduce the foam; beer taps only operate completely open or closed. If you open it halfway (which is what all of my friends do when they use the tap), it causes the beer to foam even more. On the overcarbing issue: the majority of packaged ales and lagers are carbed over 2.45. At 37F and 8 PSI, you should only get 2.2 volumes. Assuming you actually want the beer to be carbonated to the same level or a little less than commercial beer, you're about right on. Given the way gas laws work, you cannot overcarb under constant pressure. Now some potential wrinkles here could be a broken gauge or possibly, your fridge is 37, but your beer is actually something lower, increasing the solubility of the gas.
At 8 PSI, 5 feet of 3/16" ID beverage line ought to provide enough resistance. Is your line 3/16"? If larger diameter, you'd need a longer length to balance. Another possibility... is 37F your actual average fridge temp (and thus your beer temp), or is that what you have your control set to? It can make a big difference. To figure out my average temp, I measured every couple minutes for an hour or so, then did the math.
