Scott:
The “Oscoda Keg Crew” tapped a pre-vacation keg last weekend. We put all our theories, charts and experiences together and recorded our findings. Here’s a compilation of what we have found, after a dozen or so kegs, including our latest observations.
The jockey box is an imperfect way to dispense cold, non-foamy beer. There’s just too much going on for this to be an ideal outdoor method: keg beer temp, jumper cable beer temp, cooling coil beer temp, ideal dispensing CO2 pressure vs. ideal non-overcarbonating CO2 pressure, fullness of keg, waiting periods before and after tapping keg, etc. Micro Matic should provide extensive instructions with every jockey box it sells that give real-world help on making these beasts work. Simple guidelines like, “turn the pressure up to 30-35 psig,” don’t begin to deal with the factors. (No offense: you have been a big help in our quest for understanding. But, frankly, we’ve reached another level on this subject and are no longer satisfied with simple “solutions.” I am not making this more difficult than it needs to be. It’s darn difficult to begin with. You are the Dispense Institute expert and I bow to your knowledge. But the grunts in the field know what works and what doesn’t.)
The jockey box is so much fun that we are willing to invest as much time and effort necessary. When it works properly, it is like an oasis in the desert. And, as long as we’re making progress, and not repeating mistakes, we don’t mind the difficulties.
The higher the pressure, the more you risk foam problems. 30-35 psig gives you great flow through the tap, but unless every other condition is ideal, you often get more foam than beer. And rarely is every other condition ideal.
You need enough pressure to drive the beer through all that tubing, but it isn’t the same amount of pressure at all times. For example, when you first tap the keg (after waiting 2-4 hours for it to settle), the tank-provided CO2 needs time to equalize with the CO2 already in the keg. I’m still not sure what the ideal starting pressure should be. Somewhere around 20 psig. But soon enough, that will not be the ideal pressure. Ideal may be higher or lower, depending on foam levels and temperatures, but it won’t be your first setting.
Releasing pressure, even before the night shutdown, seems to calm the foam problem and help you find the ideal dispensing pressure. After our first pressure release, we were pouring glasses of pure liquid (no foam) at a comfortable rate (16 oz. in 6 seconds). The post-release pressure reading was 12 psig. We were able to stay at this pressure level for the remainder of the day.
You mention that we will need “an endless supply of ice” to make my theories work. Guess what? You need an almost endless supply of ice no matter what methods you use! Attention all prospective jockey box buyers: you will spend $15 to $30 on ice for each keg, depending on how long you want to keep the beer flowing. You can buy a lot of beer for $15-$30, so you really have to love draft to go through this much trouble and expense. You can let the keg temp increase (use less ice) but that puts you into a whole other pressure situation that gets complicated fast.
The jockey box is a low-tech, expensive, frustrating mother of a great way to drink beer. I’m willing to share experiences and methods with anyone on this subject.
Thanks,
Wayne
|