Custom Home Seltzer Setup - Need Help Troubleshooting

[El Turk]

Hello All,

I've read pretty much every post on this forum covering home seltzer setup, which led me to build my own. The basic concept is modified fridge in crawl space houses RO tank + big mac (which is fed by a 20 lb CO2 tank), with trunk line coming out of the fridge and feeding bar sink on first floor. The sink has one of these faucets: ALFI brand AB2042 Solid Stainless Steel Kitchen Faucet & Drinking Water Dispenser Combo The water paths in the faucet are completely stainless. No brass.

The water that comes out is very cold (fridge set to 33 +/- 2 degrees via Inkbird), but hardly carbonated. This is true whether the pressure is set to 45 PSI or 100+ PSI. I'm looking to get the water way more carbonated, but it's just not happening. Any ideas? I am happy to post more detailed specs of the setup (and/or pics), but figured I would start with this.

The only thing that I can think of is that the seltzer is coming out with a ton of force if I turn the faucet up all the way. If I don't, it sputters a fair amount. So, the pressure imbalance could be causing pressure loss upon distribution. But I have read a bunch of conflicting info on this (line should be as short as possible vs. as long as possible) and am really not sure exactly what's happening.

Separately, the initial 2-4 second of distribution is warm because I haven't started cooling the trunk line yet. Will do that once everything else is working.

 

[doug293cz]

What is the length and inside diameter of the tube that feeds water from the tank to the faucet? Just like beer dispense lines, the flow resistance of the dispense line needs to balance with the CO2 pressure. For 3/16" ID line, you need approximately 1 foot of line for every PSI of pressure. More info here.

How is the CO2 feed into the storage tank? Is there a carbonation stone in the liquid on the end of the CO2 input line?

Brew on

 

[El Turk]

What is the length and inside diameter of the tube that feeds water from the tank to the faucet? Just like beer dispense lines, the flow resistance of the dispense line needs to balance with the CO2 pressure. For 3/16" ID line, you need approximately 1 foot of line for every PSI of pressure. More info here.

How is the CO2 feed into the storage tank? Is there a carbonation stone in the liquid on the end of the CO2 input line?

Brew on

Thanks. I know the formula but honestly I have read a fair amount indicating that it doesn't really apply for seltzer. Are their any alternatives?

I don't use a stone. I use a big Mac.

 

[doug293cz]

Thanks. I know the formula but honestly I have read a fair amount indicating that it doesn't really apply for seltzer. Are their any alternatives?

I don't use a stone. I use a big Mac.

Why should the physics of water be different than beer? With the viscosity being lower for water, the line lengths needed would be a little longer.

I'm not familiar with how a "big Mac" operates (although years ago I made a lot of them. )

Brew on

 

[doug293cz]

Ok, did some quick Googling on the Big Mac. It appears to work by misting water into CO2 filled headspace in a holding tank, which is probably the fastest way to saturate a liquid with CO2. So, it is unlikely that this is part of your problem (unless it is malfunctioning.) That leaves you with dispense line as the likely source of the problem.

Brew on

 

[doug293cz]

Also, I looked at your combo faucet. It could be (speculating here) that the internal geometry of the faucet has flow discontinuities that help nucleate bubbles in the flowing water, causing CO2 to dissipate during dispense. Do you know of others who have successfully used the faucet you are using to dispense soda water?

Brew on

 

[El Turk]

Also, I looked at your combo faucet. It could be (speculating here) that the internal geometry of the faucet has flow discontinuities that help nucleate bubbles in the flowing water, causing CO2 to dissipate during dispense. Do you know of others who have successfully used the faucet you are using to dispense soda water?

Brew on

This is what I'm concerned about. I don't know of anyone else who has successfully used the faucet. I suppose I could try using a pluto gun (or soda gun if you don't think a pluto gun will work) and if that works, then I know what the issue is. Is there any way to decrease the pressure before it gets to the faucet so that I don't need to worry about that issue?

 

[doug293cz]

This is what I'm concerned about. I don't know of anyone else who has successfully used the faucet. I suppose I could try using a pluto gun (or soda gun if you don't think a pluto gun will work) and if that works, then I know what the issue is. Is there any way to decrease the pressure before it gets to the faucet so that I don't need to worry about that issue?

Sufficiently long tubing reduces the pressure at the faucet, however that may not be enough prevent excessive bubble neucleation. Trying a Pluto gun is a good idea, as it is made for dispensing carbonated beverages.

Brew on

 

[Bobby_M]

What kind of tubing are you using now? I'm using 39 feet of 4mm ID EVA barrier tubing on my seltzer line and it pours great at 30 to 40 psi.

 

[El Turk]

So I just wanted to circle back on this as, hopefully, it will help provide guidance to others down the line (so to speak). I replaced the ALFI faucet with a Wunder-Bar gun (Mark 4) and the issues I was having have dissipated (sorry, can't help the puns). I am now getting very bubbly seltzer. I would love to have a better understanding of exactly how to optimize the bar gun for this (i.e., seltzer only) setup, but the literature on it is a bit confusing. Either way, the faucet was obviously the biggest issue, and that is now resolved.

Just to be clear (again, for future reference), at least when using the bar gun for seltzer, I don't think you need to balance your lines. I am using about 6 feet of 1/4" ID line, serving at ~110 PSI and am not getting any sputtering any more. So I think you really just need to make sure you have a dispensing mechanism designed for carbonated water.

I suspected this, given the following (from another site):

A soda dispenser head is much more sophisticated than a simple water faucet. It must be constructed to control the relatively high liquid pressure (100 psi) while not subjecting the liquid to physical forces that would tend to nucleate the dissolved CO2 (passing through narrow orifices or rapid change of cross-sectional flow rate). Modern dispenser valves consist of a specially articulated type of O-ring known as a "banjo", spring- or solenoid-actuated levers to actuate the banjo pressure against a stop, and a specially designed set of passages and diffusers to reduce the energy of the high-pressure flowing soda to a gravity fall. The design also attempts to minimize the thermal mass and conductivity of the containment path, so as to avoid rewarming the chilled product. To all this sophistication is added a second circuit for syrup metering and dispensing, which is not a concern for simple seltzer delivery.

I still have a bit to learn about the Wunder-Bar gun, and a bit of tweaking to do, but I think this has actually been reasonably successful.