Foamy Second Beer Problem Notes

[Clint Yeastwood]

Months ago, I complained about inconsistent pours. I would get a decent first beer out of a tap, but when I poured a second beer later, I got way too much foam.

It looks like something is happening in the tap and line after the first beer.

Tonight I poured 4 beers; wheat ale at about 3.2 volumes. First one was perfect. About an inch of foam, which is what I wanted. Second and third beers were too foamy.

I noticed a lot of the foam appeared as soon as I started pouring. As the pour continued, things went as they should.

On the fourth beer, I decided to pour out the first blob of foam that came out. Probably half an ounce of beer if all the bubbles were popped. I got a fine pour after that, so the problem is all in the first second.

I'm using Nukataps without flow control, hooked up to EVAbarrier (short) and Kegland plastic flow control disconnects. I am pouring beers quite a while apart. I don't know what will happen if I pour two beers in quick succession. If I pour beers a day apart, they will both be fine.

 

[day_trippr]

A video of this phenomenon might be helpful. Also, how far apart in time were those four successive pours?

When it comes to dysfunctional dispensing, the "first pour" syndrome leads by far. I don't think I've ever read of a "second pour" syndrome. Have to think about what might cause that

Cheers!

 

[Clint Yeastwood]

I don't know how far apart they were, because I am sitting here farting around on the web, enjoying this beer immensely in spite of the fact that I am told my water has way too much iron. Maybe 45 minutes?

If the problem were due to the warmth of the tap, you would expect it to be a big deal in first pours, but it isn't. Maybe it has something to do with the recent agitation of the beer.

I think I should adopt a policy of pouring the first half-ounce into me instead of the sink.

 

[Clint Yeastwood]

Moving liquid that goes into a small tube from a big container has lower pressure than it did before it went in, so if it's carbonated, bubbles should form. Liquid that is stationary will have the same pressure in the keg and beer line. Or maybe that's wrong. Maybe Bernoulli wasn't thinking about liquids that were full of dissolved gas.

Sometimes I hate having a physics education instead of an engineering education. Physics is all about ideal situations and simplifying assumptions. No air resistance. No turbulence. No friction. Engineers have to deal with reality.

 

[micraftbeer]

Maybe there's some sort of a drainback phenomenon happening.

Thinking through what could beer happening in a 45-minute spaced pour that's not there with 1-day spaced pour...

You're right that if it was tap temperature, first beer would suck.

If it was big volume to small volume, it would be there all the time.

 

[hottpeper13]

I hope you're cutting the tubing for the duotight with a tubing cutter for a even cut. If the cut is not square the gap will cause the liquid to form an eddie current and the extended time (overnite) allows the CO2 to reabsorb.