co2 Pressure (PSI) for force carbonating water

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pixelkeg

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Hi,

I just got my DIY water carbonation system delivered. I bought a 5 lb. co2 tank, a corny keg, a bottle cap for carbonating in 2 liter bottles, and the 2 gauge regulator.

Went and had a CO2 tank filled. And tried to carbonate a 2 liter bottle of water first with that cap. But when I turned the gas on, the tank gauge only showed a little over 500 psi, and the second line was not even going above 20 psi.

So I thought maybe they did not fill the CO2 tank right. So I went to another place that exchanges the tanks and got a full tank. It was definitely a lot heavier, so I'm sure it's full.

Got back home, re-connected everything, now the tank pressure gauge is reading about 1000 psi, but the second one is still only around 25. I also took a screw driver and closed that screw on the regulator all the way, and it still won't go any higher than about 25. Am I doing something wrong? Shouldn't it easily go to more like 50+? What PSI do I need to carbonate?

And then once i hook up the corny keg, what pressure do I need to carbonate in there? and do I leave the tank open, or close it after a while and re-open for serving?

I've read a lot of posts on this site, but haven't really found a step by step guide for carbonating water in a corny keg.

I'm also considering getting a little fridge to store these in, not sure if I really need one ore not, and how it'll affect the carbonating process.

Thanks.
 
There are two gauges on your regulator (assuming you have a pretty standard setup). One gauge measures the pressure inside the C02 tank. That's the one with pressure over 500. The little gauge measures the pressure that your applying to the liquid inside your corny keg, that's the one with the smaller scale, it should be able to go above 25, but you probably don't really want it to 25 PSI is a lot of pressure. I'd start at 10PSI, test it in a week or so and then adjust it up as needed.

Keep in mind that it takes time to carbonate a liquid. It'll probably take about a week (very broad rule of thumb) to hit your target carbonation, but it depends upon the temperature of the liquid as well. You can shorten this process by shaking the keg to get more C02 into solution. Do some searches for force carbonation on this site and you'll find out all you need to know.

There's a table here that will help you figure out how much pressure it will take you to hit your target carbonation level:

http://www.kegerators.com/articles/carbonation-table-pressure-chart.php
 
first thing that comes to mind. did the hissing stop? if you hear hissing after you turn the gas on that means that its flowing. if it never stops hissing then you have a leak somewhere. if the hissing has stopped and the regulator screw is all the way in check for leaks with soapy water.

now assuming this is your problem and you fixed carbonating is easy. you need to know what the temp of the liquid is and what your desired carbonation level is. go here to get the PSI for your desired carbonation level at the temp of the liquid. this calculator is designed for beer so i don't know how accurate it is for ordinary water but it should get you in the ballpark. you leave the tank open during the entire carbonation process. as the CO2 gets absorbed into the water more will come out of the tank. once carbonation is done you can close and disconnect the tank.
 
I do 2 litres of 60% any juice + 40% water. Chill to 33F or so. Apply 50 pounds co2, remove co2 line and shake. The bottle will shrink in as the co2 is absorbed. Repeat. It's good to go, or you can refregerate for a couple of days and the carbonic acid bite will subside. Apple, pomegranite, cherry and grape are my favorites. I haven't tried plain water, but I'd process it the same way.
 
As for the wieght of the tank, did you buy a new aluminium one? if you did and they swapped it for a steel tank then that is the weight difference you a feeling not the amount of CO2 in the tank.
What way were you screwing the regulator to adjust the pressure, most are CW increase CCW decrease. But if you have it set at 25 PSI and turn it CCW to decrrease the pressure the neddle will not go down as there will still be 25PSI of pressure in the keg (it will only go down if you depresurise the keg or take the QD off and depressurise then line by pushing in the QD poppet)
 
Ok, figured out one issue, the regulator had a nut below the screw that i needed to undo a little so that the screw could go a little deeper. Now I can get it to go to 30-40 psi. So that part works.

But I tried to carbonate 4 gallons of water, and not getting good result. I hooked it up yesterday evening, shook the keg a little, then rolled it for a while, then re-hooked up the gas. This morning, it's coming out with a lot of preasure, but the water isn't bubbly. Is that because it's at room temperature? I did put a bunch of ice in it when I started carbonating, but I don't have a fridge for it yet.
 
to carbonate at room temperature, you'll need at least 100psi which is what motor-driven carbonators operate at. it can be done in a corny since they're good to 130psi.
 
If I do water I will chill it and carb aroun 30-35psi. You need a good bit more pressure then beer. Plus it takes about a week of sitting there under pressure before it finally tastes carbonated.

Oh and about the CO2 tank pressures. Pressure reading will not tell you how much CO2 you have in the tank. It only tells you when it's empty.
 
So after you chill the water, does it need to stay chilled, or is it ok to leave the keg out in my pantry after the initial carbonation to sit for a week? And do you leave it connected to the tank after a week, or you disconnect after that?
 
So after you chill the water, does it need to stay chilled, or is it ok to leave the keg out in my pantry after the initial carbonation to sit for a week? And do you leave it connected to the tank after a week, or you disconnect after that?

after the water is carbonated you can store the keg at room temperature. however, you won't want to serve it until it's chilled again..

canned beer and soda sit out at room temperature with no carbonation loss all of the time.
 
I realize this is an ancient thread, I just wanted to add-to, support and generally put in a few comments for anyone else who comes here for a search. (My search was about # CO2 volumes for water. I've since learned/decided that you kind of can't over-carbonate water, it just gets better and there's no head to worry about :) )
  • CO2 is sold as a liquid and the room-temp "there is still liquid CO2 in the tank" pressure is around 750 psi. I can be a little higher or lower based on room temp; you're basically measuring the "boiling pressure" of the CO2.
  • ...As such, when the needle starts to drop below 500psi, there's no more liquid CO2, you're just draining off the [small amount of] gas that's still in the tank.
    NOTE: This is different from other compressed gasses that are sold as compressed gas (N2, O2, scuba-air, etc), and you basically get a tank at around 3000psi and can watch the needle go down as it's 3/4, 1/2, 1/4 full. Not so with CO2; you only get the "it's almost out" warning, as above.
  • As mentioned, water (and everything) absorbs CO2 better at cooler temps. My carbonate water in a keg @ room temp routine is...
    • Fill keg with (sanitized!) water; leave some headroom for CO2.
    • Apply ~30-40psi. (I use Sanke kegs, which have a burst valve at 60psi, so I try not to ruin them!)
    • Shake as desired. If you do a fair bit of shaking, you can have carbonated water in a few hours. If you don't shake at all, it'll take about 3 days.
      • The "Fake shake":
        • Turn off the input CO2
        • Let the accumulated CO2 out of the tank
        • Turn-back-on the input CO2.
      • This at least makes the CO2 bubble through the liquid.
      • All you're doing with shaking is increasing the surface area of the liquid, allowing more dissolving. Bubbles are also increased surface area. I actually have a little rubber mallet on a motor that bangs on the side of the keg ever 12 sec (5 rpm) that does a decent job of "shaking" so I can get carbed in about 3-5 hrs at room temp.
    • I store my carbonated water in the cooler at (and serve at) ~14-15psi. It may or may not pick up extra carbonation over time; I'm not really sure. Nobody's complained, yet!
Have fun!
 
Good summary, You can get a carbonation cap for corny kegs, this has the standard PRV but also a third gas post which is in the lid this has a long dip tube and a carbonation stone on it. You use this post at the start and you make a lot of tiny bubbles this way so carbonation is quicker.
Shaking the keg accelerates the process even more.
I'd recommend to ALWAYS have a non return valve on the gas side to prevent accidents, or " do you feel lucky".
 
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