corny at 110psi (seltzer)

Is it unrealistic to expect a corny to handle 110psi? I know they're rated to 130. The pressure relief valve on mine leaks at 110, but not at 100.

In case you're wondering about the pressure, this is NOT for beer. It's for a continuous seltzer setup: tap water + C02 > McCann's Big Mac carbonator > 20' 5/16" ID line > 3 gallon corny > 35' 1/8" ID line > Perlick 525ss.

Everything functions at 100psi, with no leaks. But we wanted bigger bubbles. Pushing it to 110 causes the relief valve to leak terribly. Should the valve hold to 130? Does it need to be cleaned/replaced if it leaks at 110?

If my equipment maxes out at 100, are there other ways to get bigger bubbles besides increasing the pressure?

coudlnt you just remove the pressure relief valve and replace it with an appropriately sized stainless steel screw... might be dangerous though ha

110 PSI? Jeeez. I had my soda water at 35 PSI and it was good for me, but to each their own.

Thoughts - for more carbonation, chill it colder? You should be able to run at 32*F or lower (the extra CO2 will drop the freezing tempertature of the water a bit), and the colder you run the more carbonation you'll pack in for a given pressure.

Otherwise, you could try replacing the valve, but I have a feeling those things aren't highly calibrated. It's just a spring holding the valve shut, and the spring should let go *somewhere around* 130 PSI. 110 PSi doesn't seem too bad.

I do applaud you for building such a high pressure system though....must have been a bit tricky to make it so it didn't blow apart at the seams, so to speak.

twobrain said:

coudlnt you just remove the pressure relief valve and replace it with an appropriately sized stainless steel screw... might be dangerous though ha

Click to expand...

It sounds like both a good and dangerous idea. The carbonator has a relief valve that pops at ~120, so (theoretically) it shouldn't get higher than that down the line. So, maybe a bit safer than otherwise. I don't love the idea of undoing a safety measure, though.

shortyjacobs said:

110 PSI? Jeeez. I had my soda water at 35 PSI and it was good for me, but to each their own.

Click to expand...

Well, as I've learned over the course of this project, there's an entirely different physics to force carbing (to which I suspect you're referring) and continuous flow. The normal operating range of motorized carbonator systems is 80-120psi. Restaurant soda systems are typically at about 100-110, as I understand it. Part of that is due to the continuous flow. Part is due to carbonating at room temperature (as a result of continuous flow). The dispensing is at 32-34 degrees.

Your observation about the calibration of the valve makes sense. Given how simple they are, at that threshold and pressure, I suppose it's unfair to expect precision.

I would not advise on any pressure over 30psi. I know the cornies say 130PSI right on the side of them, but that is max for new condition and most cornies are decades old. This summer past I had someone testing our kegs that set the air compressor at 50PSI figuring he was saving time and making life easier (I use 5PSI). Long story short about twenty pieces ended up in the scrapyard from bursting at the welds and a few that made it out burst somewhere in transit. I even had one burst in the warehouse while I was present and it managed to project itself out of the stack and land on the floor.

Yikes. Thanks for the warning.

disabling safety features on high pressure vessles is a great way to kill someone. you shouldnt need two brains to figure that out. a keg in good condition should be able to handle its rated 130psi. if your kegs are not in good condition, that number should obviously be derated accordingly.

when i make seltzer, i normally hit it with 50-55psi for a while, then drop down to mid 40s. that is about the carbonation level as you will get in a normal can of seltzer or higher-carbonated soda.

above 100psi seems way excessive for carbonated water. you would need atleast 100 feet of serving line in order to get any of it in the glass.

also remember, you will be wasting twice the amount of CO2 at 100psi, as you would at 50, while pushing the CO2 out of the keg. you could use the pressure in an empty keg to carbonate another, but normally people just vent it and refill, which is a huge volume of wasted CO2.

gromfy said:

Is it unrealistic to expect a corny to handle 110psi?

Click to expand...

Yes, it would be a very good idea to purchase a stock pressure tank that can handle 250-300 psi. Operating any storage tank at or near its design limit is a bad idea.

Is the tank on the carbonator too small or are you using the second tank for chilling?

holy moly that's a lot of psi. My better half loves having seltzer on tap so typically i have one serving and one carbing, i do both at about 35psi and it's perfect

35psi and about 37F for me. Even with 5min of shaking the day after chilling, it still takes a week to get the water really spicy. There's def more snap to my soda water than the commercial brands I've had. I've also been experimenting with my minerals to good effect.

audger said:

disabling safety features on high pressure vessles is a great way to kill someone.

Click to expand...

It's a terrible idea disabling a safety device. Agreed.

I won't pretend to be an expert on the proper pressure for seltzer. I will say that I fully understand that force carbed seltzer (and seltzer in a can) is around 40-50psi (max). I also had assumed the same to be true of systems using a motorized carbonator. I have subsequently been disabused of the latter notion on this thread: https://www.homebrewtalk.com/f95/cloudy-flat-seltzer-using-motorized-carbonator-270664/#post3327092

There's apparently a tremendous difference between force carbing COLD, sealed water and carbing ROOM TEMP continuous flow seltzer. Indeed, the manual to the McCann's carbonator states the the normal/suggested operating range for the unit is 80-120psi.

audger said:

above 100psi seems way excessive for carbonated water. you would need atleast 100 feet of serving line in order to get any of it in the glass.

Click to expand...

Well, that's partially true. Without restricting the flow, it certainly dispenses from a Perlick too violently to fill a glass. It's more like a CNC machine than soda fountain!?! I put in 30' of 1/8" line for dispensing, and that solved the problem.** The other option is to use a seltzer faucet (e.g., http://www.kegkits.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=21-2210-90R&Category_Code=), which has a built in compensator ("Internal compensator - used to reduce foaming - no long coiled up beer line needed"). The same is true of real soda fountains (http://www.kegman.net/products/Wall-Mount-Post%2dMix-1-Faucet-%2d-1755.html). These have leather washers to reduce flow.

In other words, while I am no expert, I do believe that seltzer is supposed to be carbed to a really high pressure in these systems, and that's exactly why soda faucets and beer faucets are engineered differently.

david_42 said:

Yes, it would be a very good idea to purchase a stock pressure tank that can handle 250-300 psi. Operating any storage tank at or near its design limit is a bad idea.

Is the tank on the carbonator too small or are you using the second tank for chilling?

Click to expand...

The second tank is for chilling. I don't know anything about pressure tanks. That's the role I thought the corny was playing.....

I really appreciate all the various thoughts. A month ago, I had never touched or thought about any of this equipment. I know a lot more now, but certainly defer to others' expertise. I know I'm not the first to do this, though. There must be a standard "right way".....

I can only assume that you want to carb that much because you are trying to serve room temperature seltzer. At 40* and 35 PSI, I can't imagine wanting more bubbles in my seltzer.

** As an aside, I'm not sure I understand why long, narrow length tubing reduces pressure -- friction? Anyway, is C02 lost through this, or just flow rate?

Click to expand...

Yah, that's exactly it. You're using the friction of the fluid flowing in the tube to slow it down. Unless it causes lots of turbulence, you shouldn't get any foaming or loss of CO2

As another aside, I'm surprised by how many "Woah, why are you pressurizing it so high? I only crank it up to 35psi, and my seltzer turns out great." responses you've gotten. You clearly stated that you were doing something different from the normal process...

For the love of God, people...read something more than the number next to those funny "psi" characters!

bblack7489 said:

Yah, that's exactly it. You're using the friction of the fluid flowing in the tube to slow it down. Unless it causes lots of turbulence, you shouldn't get any foaming or loss of CO2.

Click to expand...

Thanks.

Sheesh, sorry...

Good luck.

There's apparently a tremendous difference between force carbing COLD, sealed water and carbing ROOM TEMP continuous flow seltzer. Indeed, the manual to the McCann's carbonator states the the normal/suggested operating range for the unit is 80-120psi.

Click to expand...

check out the carbonation volume vs temperature vs pressure graph. yes, in order to get the same # of volumes of CO2 to dissolve at room temperature, you have to crank the pressure up.

theres also a big difference between carboatING and carbonatED. once its already carbonatED and canned/bottled/kegged, the CO2 will mostly stay in suspension in the liquid even if it warms up again. so you could carboate the water at 30-40psi at 35 degrees, then warm the keg up to room temp. the internal pressure would rise slightly, but no where near 100+ PSI that would be required if you tried to carbonate it warm.

bblack7489 said:

For the love of God, people...read something more than the number next to those funny "psi" characters!

Click to expand...

would you have reacted any differently than those people if he had said he wanted to carb beer at 100psi...? probably not.
hows the weather up on that soap box?

audger said:

theres also a big difference between carboatING and carbonatED. once its already carbonatED and canned/bottled/kegged, the CO2 will mostly stay in suspension in the liquid even if it warms up again. so you could carboate the water at 30-40psi at 35 degrees, then warm the keg up to room temp. the internal pressure would rise slightly, but no where near 100+ PSI that would be required if you tried to carbonate it warm.

Click to expand...

That's an important distinction, and one I hadn't much thought about. Thanks.

The challenge I'm trying to overcome is never needing to think about this (besides CO2 recharging) once connected. We're going for on-demand, continuous, never-touch-the-system/keg/etc-again soda water. That means carbing filtered tap water at room temp.... Or am I missing something?

Take an aluminum can, crush it flat then start bending it back and forth. Sooner or later it breaks due to the fatigue. Every time you pressurize and depressurize something, you're doing essentially the same thing. Your keg has had an unknown number of cycles on it and an unknown amount of fatigue. Are you willing to subject yourself and your family/friends to the risk of a piece of equipment being stressed to a level you're not sure it's capable of taking?

Pilotpip said:

Are you willing to subject yourself and your family/friends to the risk of a piece of equipment being stressed to a level you're not sure it's capable of taking?

Click to expand...

Of course not. My new 3 gallon corny has NOT been pressurized and re-pressurized more than a few times. Also, knowing a lot about product liability and industry standards, it is nearly impossible for me to believe that a company would rate something to 130 that could degrade substantially over normal usage. Moreover, that's why there's a relief valve (which started this whole thread). Certainly, that will leak before shrapnel flies. Your hot water heater gets to high pressure, but most people feel safe with them because of relief valves and similar safety devices.

So, no, I would never want to expose my family to risk. But I have some confidence in the materials I'm using and the manufacturers of them.

All of that said, I more than appreciate the feedback and concerns. I reached out because I know people here have A LOT more experience than I do. If there are other suggestions, I'm open. But as far as I understand it, this is not an atypical setup for continuous flow seltzer....

The rating on a cornie is not intended to be the operating pressure. They were designed for pre-mixed, pre-carbonated sodas that were served around 40 psi. That pressure margin accounts for tanks warming up occasionally.

back to your problem:

Most carbonators have a small tank (1-2L) where the water & CO2 mix.

Another possibility would be to pre-chill the water before it goes into the carbonator. That would let you reduce the pressure in the whole system. The downside is that whenever the system is just sitting, the water temperature will go back up.

A third possibility is to use a plate chiller (like in a jockey box) instead of the cornie.

Or use a coil of stainless steel tubing inside your refrigeration unit instead of the plastic tubing. I'll probably be taking this approach when I build my new cabinet. The soda water will sit at the 40-45F of the cabinet and get the final chilling as it flows to the tap.

Pilotpip said:

Take an aluminum can, crush it flat then start bending it back and forth. Sooner or later it breaks due to the fatigue. Every time you pressurize and depressurize something, you're doing essentially the same thing. Your keg has had an unknown number of cycles on it and an unknown amount of fatigue. Are you willing to subject yourself and your family/friends to the risk of a piece of equipment being stressed to a level you're not sure it's capable of taking?

Click to expand...

That's not the best example. For one, we are not taking the kegs into the plastic deformation regime. Also, aluminum has no fatigue limit, whereas steel does. The fatigue limit is a stress that if not exceeded, will not cause fatigue.

Your rv is just out of calibration. If it is rated for 130 psi some high paid engineer put some factors of safety in. Get a new lid and pump it up. Any pressure vessel should be able to hold it's rated pressure indefinitely, that's why they rate them, assuming no damage/corrosion. Worst thing is you'll leak out your rv and lose some co2.

sapperxl said:

Your rv is just out of calibration. If it is rated for 130 psi some high paid engineer put some factors of safety in. Get a new lid and pump it up. Any pressure vessel should be able to hold it's rated pressure indefinitely, that's why they rate them, assuming no damage/corrosion. Worst thing is you'll leak out your rv and lose some co2.

Click to expand...

I agree in theory... but in practice they should also be inspected and tested regularly. Metal does fatigue and wear over time when it is under stress. This is why CO2 tanks have dates on them...

david_42 said:

back to your problem:

Most carbonators have a small tank (1-2L) where the water & CO2 mix.

Another possibility would be to pre-chill the water before it goes into the carbonator. That would let you reduce the pressure in the whole system. The downside is that whenever the system is just sitting, the water temperature will go back up.

A third possibility is to use a plate chiller (like in a jockey box) instead of the cornie.

Or use a coil of stainless steel tubing inside your refrigeration unit instead of the plastic tubing. I'll probably be taking this approach when I build my new cabinet. The soda water will sit at the 40-45F of the cabinet and get the final chilling as it flows to the tap.

Click to expand...

Thank you for the suggestions. The first one is clever, but, unless I keep the motorized unit *IN* the refrigerator, it won't work. And I think that's a bad idea. The plate chiller is a good idea, and would work but for our HEAVY consumption. That thing would warm quickly unless it was sitting under ice -- and it won't and can't be.

Your last suggestion is very interesting -- the coil of stainless. If I could create, say, a gallon of capacity, that might be the smartest solution. But that would probably need to be a very very large coil.

I appreciate you taking the time to read through everything and address the issues I raised. Thank you.

What is wrong with an ice bank?... that is what actual soda fountains use. With a large enough bank your flow is nearly limitless (within any reasonable usage).

Danaldor said:

I would not advise on any pressure over 30psi. I know the cornies say 130PSI right on the side of them, but that is max for new condition and most cornies are decades old. This summer past I had someone testing our kegs that set the air compressor at 50PSI figuring he was saving time and making life easier (I use 5PSI). Long story short about twenty pieces ended up in the scrapyard from bursting at the welds and a few that made it out burst somewhere in transit. I even had one burst in the warehouse while I was present and it managed to project itself out of the stack and land on the floor.

Click to expand...

I think the guy using 50 psi is a much smarter idea than using 5 psi. At least then you know the kegs (that survive ) can take 50 psi, check at 5 psi tells you they will not leak (whcih I am guessing is what you were checking for) but doesn't indicate if they are definately fit for use at anything above 5 psi. Although he probably should have filled with water first to avoid the issues you mentioned and not stored them at that pressure! An actual pressure test should really take it above 110/125/150% of the design pressure, and use water to do so.

sapperxl said:

Your rv is just out of calibration. If it is rated for 130 psi some high paid engineer put some factors of safety in. Get a new lid and pump it up. Any pressure vessel should be able to hold it's rated pressure indefinitely, that's why they rate them, assuming no damage/corrosion. Worst thing is you'll leak out your rv and lose some co2.

Click to expand...

I would say that the PRV was meant to release at below 130 psi, the tank is rated for 130 psi so you would want the PRV to release at something under that. You can never assume no corrosion/damage and that is why pressure vessle are inspected/test periodically.