Carbonation Cornucopiae

CO2 Tank
Connector Gizmo
Carbonation Cornucopia

So we wanted a way to avoid having to schlep soda water bottles home after shopping. Aside from the inconvenience, the added carbon debt of burning energy to collect water forced into plastic bottles and then carbonated, and then dumped these wonderfully engineered high-pressure containers into landfill just feels wrong. So we got a Sodastream carbonator.

But then I looked at how inconvenient the whole Sodastream carbon refill racket actually is. First of all, the company prints all this legalese EULA shite onto its carbonator tanks basically warning you of “penalties” if you refill them yourself. Apparently this serves to warn off a sufficient number of paintball shops and outdoor shops from refilling them. And then because of US Mail restrictions, if you use mail order then you have to sign for delivery of the canisters because they are high-pressure, “high-risk” items needing special delivery. And many of the places that sell Sodastreams either don’t carry the refills at all or are out of stock. And the final insult is that because of this protectionist razor blade model, the actual monetary savings on home carbonation vs purchased commercial carbonated drinks are not that great. You save only around 30%-50% off the retail price of pre-packaged soda (for one of the most common gases in the atmosphere and commercially available, this is ludicrously expensive). Plus, I really did not want to get into the habit of supporting a commercial enterprise based out of illegally appropriated colonial settlements that displace autochthonous inhabitants.

Knowing how common CO2 is for commercial applications, I figured there had to be a better, cheaper way. I found this excellent site explaining how to build home carbonation systems in excruciating detail. However, although these things look cool in a sort of steampunky way, they do not pass the Wife Test without a lot of in-home modification and cabinetry. But from this site, I learned that obtaining large-volume CO2 tanks is as easy as finding your local gas welding supply outlet. Via Yelp, I got a CO2 “20 Pound” siphon tank.

A siphon tank is where the outlet valve is directly connected to the liquid CO2 at the bottom of the tank by a tube. For my carbonation system, you have to ask specifically for a siphon tank because the more usually dispensed non-siphon tanks simply drain the top-of-the-tank gas-phase CO2 through the outlet and this does not create enough pressure.

There are two choices with these huge CO2 tanks and a Sodastream home carbonator. The simplest option is to connect the tank directly to the carbonation machine using a regulator, but then you are back dealing with the issue of a huge, industrial-style CO2 tank in your kitchen and a bulky hose and regulator that must be hidden away. In this case, however, you do want the non-siphon CO2 tank.

The slightly more complex option is the one I went with, which is to get a connector gizmo that lets you disconnect the tiny Sodastream CO2 bottle and, connect ingit temporarily to the large CO2 tank, you can refill it and then replace it into the discreet, Wife-Approved Sodastream unit (where it’s good for 50 litres or so of carbonation).

The one little kink in this is that in an attempt to protect its business model, Sodastream has sabotaged its tiny CO2 bottles with a borked valve that clamps shut if you attempt to fill it at anything like a decent rate. You can fiddle with this and try to remove the clamp yourself (sounds difficult, and do you really want to mess around with high-pressure valves?), you can fill it at a slow rate and put up with occasionally having to wait several minutes to retstart filling if you trigger it, or you can buy a replacement, unborked valve.

Replacing Sodastream’s crappy valve takes around three minutes. Attaching the regulator gizmo to the tank takes around two minutes. Refilling Sodastream’s tiny bottle takes around a minute and involves basically turning a tap. Bracketing the large CO2 tank to the wall to prevent falls and accidental rocketry experiments took me significantly longer than anything else because I am quite fundamentally crap at DIY.

The initial cost to buy the large CO2 tank runs anywhere between $100-$200. You can buy these tanks shipped to you empty for cheaper, and then fill them at the welding suppliers. But refilling tanks takes time and will piss them off, and they will charge you extra. Most of these places are set up to simply exchange tanks (total time, around two minutes or so), and charge something between $10-$30 to swap out a tank. Each large tank will carbonate around 1,000 L of water, and so the net cost per litre is only pennies. Add in the cost of the equipment and depreciate it over, say, a five-year span (normal for industrial equipment but I expect the regulator to last far longer) and your marginal cost goes up a few pennies per litre. Effectively, you now have a carbonation cornucopia machine.

After all this, you have the satisfaction of not creating energy-intensive plastic waste. You are now not burning fuel to move water across geographic distances (hopefully the CO2 credits here more-than-balance the CO2 debt from all this carbonation!). You are not supporting a company deriving at least some of its profits from illegally occupied land. You have a carbonation cornucopia machine. You may learn, as I did, that there’s an impressively petty flamewar between the people I bought the gizmos from and their competitors which is mainly ugly sock puppetry and bad grammar with notable outbreaks of e-lawyering. And finally, you have learned the location of your local welding supply store, which I found out to be an extraordinary place where you can walk in off the street and basically buy huge tanks of oxygen and hydrogen from desk clerks who look like carny folk. If you decide you want to potter around with ballistic missiles as a hobby, you now know where to go.

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