Pressure barrel dispensing foam well at least

[jezbrews]

So my pressure barrel is at around 8.8 psi at a temperature controlled fridge held at 10.5-11.5°C, so somewhere between 1.7 and 1.8 volumes of CO2, not bad for a porter. My question is, what can I do when opening the tap to prevent just getting an embarrassing glass of foam that I have to wait a painfully long time to drink? I understand lengths of narrow diameter pipe are often used with kegs at least to prevent CO2 breaking out, can I do something similar with a pressure barrel?

 

[Buffers brewery]

Hi @jezbrews . Does your PB have a top or bottom tap. PBs with top taps can sometimes develop a gas leak into the tap so every time you pour a beer you get a lot of foam.
If it’s a bottom tap of the half turn type (not a sparkler tap) I found that a slow pour, i.e. just opening the tap a crack, will create more foam than opening the tap wider for a “faster” pour. But can be frustrating to find the best position.

 

[Stevieboy]

In my experience of both top and bottom taps, a long slow pour is the best option. Get a tray set up and dribble it in....

 

[Agentgonzo]

Does it dispense from one of those cheap white plastic taps?

I had those for a long time and also it just dispensed foam. Part of the problem is that it's going from a high pressure to a lot pressure in a very short distance, and short of dropping the pressure, there's not a lot you can do about it (this is why keg setups have longer lines than strictly necessary). When the pressure drops suddenly, a lot of tiny bubbles come out of solution and that's the foam.

Compounding this problem in the tap itself. The plastic design means the beer has to go through 90° degree turns though the tap. This causes turbulence, and additional low pressure areas within the tap that makes more CO2 come out of solution.

Then, in addition to this, the design means that you tend to only open the tap a little bit, and that means the beer rushes through this tiny gap at great speed and this reduces the pressure even more (Venturi effect) and makes even more CO2 come out of solution. Counter intuitively, a slow pour will get you more foam (though admittedly, a fast pour will probably not stay in the glass very much).

So what can you do about it?
1. Reduce your serving pressure until to stops foaming
2. Replace the taps on your pressure barrel. I got some plumbing stuff - ball valve connected to a bent piece of copper pipe that doesn't make the beer go through a 90° turn. (This is also a lot more controllable than a plastic tap)
3. Pour faster (hopefully with the help of the above this can be made manageable).

That worked for me. Up until I made those changes, I used to have to dribble out a pint of foam from the cask until the pressure reduced to acceptable levels like stevieboy does.

 

[Buffers brewery]

You could try a Sparkler tap. I changed all my King Keg taps to Sparkler taps and got a better pour. Didn't brew stouts and porters though.

 

[jezbrews]

Hi @jezbrews . Does your PB have a top or bottom tap. PBs with top taps can sometimes develop a gas leak into the tap so every time you pour a beer you get a lot of foam.
If it’s a bottom tap of the half turn type (not a sparkler tap) I found that a slow pour, i.e. just opening the tap a crack, will create more foam than opening the tap wider for a “faster” pour. But can be frustrating to find the best position.

It has a bottom tap. Not sure what you mean by a half turn vs sparkler, but I do think I know what you mean by turning it on full produces less foam, although of course it is faster so just need to be careful turning it off in time!

In my experience of both top and bottom taps, a long slow pour is the best option. Get a tray set up and dribble it in....

The long slow pour is what gives me 90% foam. I might actually try turning it open full and then reducing it gradually.

Does it dispense from one of those cheap white plastic taps?

I had those for a long time and also it just dispensed foam. Part of the problem is that it's going from a high pressure to a lot pressure in a very short distance, and short of dropping the pressure, there's not a lot you can do about it (this is why keg setups have longer lines than strictly necessary). When the pressure drops suddenly, a lot of tiny bubbles come out of solution and that's the foam.

Compounding this problem in the tap itself. The plastic design means the beer has to go through 90° degree turns though the tap. This causes turbulence, and additional low pressure areas within the tap that makes more CO2 come out of solution.

Then, in addition to this, the design means that you tend to only open the tap a little bit, and that means the beer rushes through this tiny gap at great speed and this reduces the pressure even more (Venturi effect) and makes even more CO2 come out of solution. Counter intuitively, a slow pour will get you more foam (though admittedly, a fast pour will probably not stay in the glass very much).

So what can you do about it?
1. Reduce your serving pressure until to stops foaming
2. Replace the taps on your pressure barrel. I got some plumbing stuff - ball valve connected to a bent piece of copper pipe that doesn't make the beer go through a 90° turn. (This is also a lot more controllable than a plastic tap)
3. Pour faster (hopefully with the help of the above this can be made manageable).

That worked for me. Up until I made those changes, I used to have to dribble out a pint of foam from the cask until the pressure reduced to acceptable levels like stevieboy does.

This does make a lot of sense.

Regarding point 1, it seems to be a pretty consistent pressure up until there is none.

Point 2, I might give this a try but I'll be honest, I just got a chest freezer to turn into a keezer. I might just invest in kegs and leave the pressure barrel to emergency brew leftovers!

Point 3 I think for now is my best choice until I get kegs and gas.