I'm hoping my plan to carbonate my kitchen drinking faucet is as easy as it seems, but would like some confirmation I'm not missing something:
In short, I want to hook my main water line up to a consumption-grade CO2 tank, the same way I would hook up a Keg. I have a separate drinking faucet connected to my main water line, and I'd like to add a CO2 tank, connected to a regulator, connected to an air line, connected to a keg coupler. The Keg coupler would also connect to my main water line, and separately connect through to my faucet. For a diagram of what I mean, check out: www.kegworks.com/blog/how-draft-systems-work/ [No affiliation].
I'm not concerned with chilling or filtering at this point, but in theory would I be able to add in a water filter that feeds into my main water line into the keg coupler down the road? Or would that create problems with making the filter system 'under reverse pressure' from the CO2 tank?
I'm also trying to avoid needing to get a separate water tank to keep under my kitchen sink as that space is limited and I'd like to keep refill trips to a minimum. If my current plan doesn't work, having a tank of filtered water that I periodically have to refill and put under my sink might be the next best thing.
I guess what I need to worry about is whether my main water line is pressurized enough to prevent the CO2 tank from simply emptying out into my water supply?Alternatively, would the pressure from the main water line 'overpower' the CO2 tank such that I would get minimal carbonation in the end product?
Per the comments, if I would need to keep the CO2 tank < the pressure of the water line (let's assume 50-75 PSI), would that sufficiently carbonate the water? If not, would it be possible to add some sort of one-way valve from the main water line that feeds into some sort of water collection tank, that then connects to the carbonation system, so that it could 'withstand' higher pressure?
Best Answer
I don't believe this is going to work very well with the set up you have described. Carbonation of water requires that the CO2 dissolve into the water. Assuming you get the pressure all worked out, the surface area between the gas and the water is going to be tiny. If it worked at all, it would dissolve into the water line itself. My guess is only a few ounces would be carbonated at most when you open the tap.
Another thing to consider is that the colder the water, the more CO2 it can dissolve. This is why a hot beer is more likely to foam out and create too much head than a cold beer. Here's a graph of that relationship:
I think you might be able to manage this with a tank, though. Basically it would be a keg but you would need to have a water supply as well as CO2 for the water to refill through. I'm not sure there's something off the shelf for this but reverse-osmosis systems have a tank so there might be a way to cobble together parts for to make it happen. I'm not exactly sure how you would make it automatically refill.
You'd want to have some sort of check valve on the water line to prevent it from flowing back into the water supply. The CO2 tank should have some sort of pressure control valve just like it would on a keg system.
This wikipedia page has some good info on this. If 70 PSI is the right number for the water line, you would probably need to release the pressure from the CO2 in order to refill the tank. The amount of carbonation could be tweaked by the pressure from the CO2 tank. The higher the pressure, the more CO2 will dissolve.
One other consideration is that it the pressure is much higher than typical water pressure, the faucet might not be designed for that and/or it could shoot out too fast.