So these barrier lines are both good and bad. I had a club member (who just so happened to be a draft tech) come look at it last night and he got me set up properly for the time being.
Here's the setup for anyone who is reading this in the future and may gain from my experience:
- 14' 1/4" Micromatic Brewmaster II barrier lines: http://www.micromatic.com/draft-keg-beer/hoses-pid-548BT1200.html
- 1/4" fittings and shafts throughout
- Perlick 650SS flow controls
- Running straight CO2 on two pressures (10psi & 15psi) for normal beers
- Running what I was told was G-mix (75/25 CO2/N2) for the nitro tap
- Keezer at 38F
Once I got the beers pouring after simply swapping out the 9' long 1/4" vinyl lines and not changing anything else, it was straight foam. Obviously, I lost a lot of resistance going from vinyl (0.85 lb/ft) to barrier (0.3 lb/ft). I poured without changing anything just to see what would happen. I wasn't expecting it to work, but wanted to check just in case the manufacturer numbers were off. I had read the Draft Quality Manual several times while building this thing, so the numbers told me that if I decreased my temperature and lowered my pressures I would likely be good to go with the 3psi difference in resistance, so I tried that.
Problem was this: even though I could get it to pour with an inch of foam on the beer, it was "coughing". For instance, the first 2-3 seconds of the pour would be normal, laminar flow. Then it would "cough" and sputter, then pour more foam. This is the opposite problem of what I had with the vinyl lines. The line beer would be a touch
foamier than the keg beer, and it tasted like vinyl line, so we'd dump it. So why the coughing and sputtering?
What the DQM doesn't tell you is that despite all of the equations and numbers, you may just have to turn the pressure up. Greg (our draft tech) looked at it, listened to my process, and poured a beer. He went to the back, turned up the pressure to 17psi, and poured a beer. By the second beer, it was pouring perfectly. Dang - I never would have figured that out by myself.
Turns out that the low resistance lines were allowing the beer to flow faster in the line than the pressure in the keg would be able to keep up with. Turning up the pressure allowed the beer to flow out at a rate as fast or faster than the low resistance lines allowed. And with a perfect little cap of foam!
Now... well, my serving pressure is all fine and dandy, but I'm going to need to experiment with how low I can turn the serving pressure (currently at 17psi, and the keezer is moving up to 38F again from 33F now) and not have coughing. If I can get it low enough, then I may not have to move to a 70/30 mix of beer gas. Otherwise, I think I'm going to have to move to a beer gas mix from straight CO2. Not really a big deal in this area, but still something else to do. In the meantime, I have the gas turned off at the regulator when we are not drinking so everyone stays properly carbonated.
As for the nearly-all-foam nitro pours, I had it originally set at 35psi (because that's what the DQM shows you to calculate for G-mix), but had turned it down to 20psi to try and knock some of the foam out. It worked... a bit. Greg advised that the G-mix probably wasn't actually G-mix at all and was likely 65/35 instead of 75/25. So I turned it down to 8psi for now and I'll see how it is pouring later tonight.
So. Pros and cons of this draft system now that it has barrier lines:Pros
- No more nasty line beer
- No more flavor crossover
- More consistent flavor due to the above points
- No more dumping line beer
- Not intuitive to figure out
- Might need beer gas
Keep in mind though, that this is a totally custom system. This isn't your standard "put shafts through a collar" type operation. These experiences may not apply to you. However, if someone is building a long draw custom system (as I have seen a few in the recent past on here) it may be of use to you.