Ultimate SodaStream Mod for Endless Seltzer

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Introduction: Ultimate SodaStream Mod for Endless Seltzer

About: Making and sharing are my two biggest passions! In total I've published hundreds of tutorials about everything from microcontrollers to knitting. I'm a New York City motorcyclist and unrepentant dog mom. My wo…

I upgraded my seltzer machine by hooking it up to a 50lb CO2 tank, with the help of my friend Ian. We're calling it "Endless Seltzer". We both really love fizzy water.

Ian Charnas is a YouTuber who does mechanical engineering, electrical engineering, and computer engineering. In his videos he makes these super fun inventions and raffles them off to support good causes - so you can win almost everything you see on his channel.

Supplies

We did some research online and found this adapter you can get that connects the SodaStream to a more industrial standard type tank. That's all that's really required for the minimum viable product, but naturally, we wanted to add a bit more engineering so we also built an internet-connected scale that keeps track of how much CO2 is left.

Supplies and Tools:

Check out the electronics components in a saved list on Digi-Key.

Although you don't have to build the electronics part of this project to enjoy the fizzy benefits, you must understand the dangers of working with a pressurized tank of gas. If it falls over and the valve is damaged, the whole thing could become a dangerous projectile. Basically a missile. The main precaution we're taking is to install a tank strap to the wall. Don't skip this step. I'm also setting up a CO2 safety monitor/alarm just in case there's a leak.

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Step 1: The Math

At my average consumption rate of one bottle (840mL) per day, this tank should last me almost seven years.

I was also interested to calculate the cost savings this setup would generate over time. The big tank works out to about 18 cents per liter of carbonated water before the equipment cost is recouped, where the subscription canister produces seltzer that is about 38 cents per liter all the time. 

Step 2: Tank Acquisition

We drove the van over to our local welding supply shop to pick up the tank, which although called a 50-pound tank, that's just the weight of the gas inside. The full tank weighs 160 lbs. So by far, the hardest part of this project was hauling it up the stairs. At least it'll be about one-third lighter when it's empty!

Step 3: Plumb to SodaStream

We did some research online and found an adapter that connects the standard industrial-type tank to the SodaStream.

The SodaStream end of the hose has a separate piece that screws in where the small tank normally would. The tank end of the adapter hose tightens onto the tank valve with a crescent wrench. I couldn't get a crescent wrench into the tight spots on the SodaStream, so I used a pair of vicegrips to tighten that. Lastly, the hose end's quick-connect plugs into the end piece.

That's all that's really required for the minimum viable product here, but we wanted to add a bit more engineering so we also built an internet-connected scale that keeps track of how much CO2 is left.

Step 4: Tank Safety

Although you don't have to build the electronics part of this project to enjoy the fizzy benefits, you must understand the dangers of working with a pressurized tank of gas. If it falls over and the valve is damaged, the whole thing could become a dangerous projectile. Basically a missile. The main precaution we're taking is to install a tank strap to the wall. Don't skip this step.

Since we're mounting to brick, we picked up a specialized masonry drill bit in the size specified by our mounting hardware instructions, and used the hammer setting on my drill to make the holes. The strap bracket then screws into the anchors, the tank and scale get into position, and the tank gets strapped in.

I intend to keep the tank valve closed when I'm not actively carbonating, but just in case there were to be a slow leak, while it's not terribly likely, I wanted to take one more safety precaution since this thing is in my house. I picked up a carbon dioxide monitor with an alarm, and installed it low to the ground near the tank.

Step 5: Circuit Prototype

To build our scale, we're using load cell sensors. These are the same types of sensors as in your typical bathroom scale. They convert pressure into millivolts, a signal that is then amplified by a load cell amplifier before outputting to our microcontroller. We wired up a solderless breadboard prototype to test out these load cells, and amplifier, as well as the LCD screen.

The microcontroller connects to the wifi and lets me know how much CO2 is left.

We goofed and got the type of load cells that can't be combined through a single amplifier, so we made do with the two amps we had and attached them in opposite corners of the scale. It'll reduce the accuracy of the scale, but then again I only need to know when it's getting close to empty, not right down to the gram.

Step 6: Build the Scale

Next up, it's time to build the scale, starting with the electronics. We soldered up a perfboard version of our earlier circuit prototype and attached the load cells with long wires.

Typically you would use four load cells to build a scale, one in each corner. Then a plate presses down evenly on the sensors, and there isn't a lot of clearance between the tall part of the sensor and the rest of it. We constructed the scale from pieces of scrap plywood I had around, and then we reinforced the corners with pieces of metal so that the heavy tank doesn't just deform the plywood onto the sensor. The scale consists of a base piece, the top plate, four sidewalls, and a middle piece where the load cells will live, which has a cutout for the electronics. No fancy woodworking here, just a few pocket holes to stick everything together.

This design is also suitable for building a scale inside a kegerator, just adjust the dimensions to fit the size of your keg.

Step 7: Use It!

Thanks for reading! I'd love to hear your thoughts in the comments below.

To keep up with what I’m working on, follow me on YouTube, Instagram, Twitter, Pinterest, and subscribe to my newsletter.

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    38 Comments

    0
    dirty_valentine
    dirty_valentine

    Tip 1 day ago

    The SodaStream adaptor has a valve built into it to hold back the CO2 pressure. It is not necessary to get the adaptor much tighter than hand tight into the SodaStream. The part the adaptor is screwed into is just plastic and it is easy to break if you screw it in to tight. I broke one just hand tightening a bottle in - had to buy a new soda stream. The extra torque of a wrench would easily snap it. Even if the seal leaks a little the SodaStream will work just fine. If it leaks significantly, give it a little extra torque and it should be fine.

    0
    ashtangakasha
    ashtangakasha

    Question 7 days ago on Step 2

    My local welding supply won't sell CO2 if they think you'll be using it for human consumption. They say that industrial CO2 contains (or might contain) trace amounts of toxic chemicals, while food-service approved CO2 is "pure CO2." I can't find anything online to confirm that, but of course there would be liabilities for a CO2 supplier if people were using it for seltzer and absorbing traces of benzene, or some such. Did you obtain food-grade CO2, or do you think that industrial CO2 is reagent pure anyway? Contaminants could be bad for industrial equipment, too, not just humans, so I should think ALL supplies of CO2 should be just pure CO2. Reagent pure, that is. Thanks for the info....

    0
    n4mwd
    n4mwd

    Answer 7 days ago

    Maybe ask a local independent restaurant where they get their CO2. My local welders don't have any problem selling me CO2.

    0
    ashtangakasha
    ashtangakasha

    Reply 7 days ago

    Thanks. I'll give that a try. AirGas refused to fill my tank because it wasn't marked for food grade gas, so my local store is being pretty careful. But I just signed up with them and will hopefully be able to get foodgrade CO2 if my application is approved. It's been a nuisance, but I really don't want to take chances if I'm about to ingest this much CO2 in beverages!

    0
    n4mwd
    n4mwd

    Reply 7 days ago

    Chances are, the food grade bottles are filled on the same machine as the welding grade.

    0
    ashtangakasha
    ashtangakasha

    Reply 5 days ago

    I suspect so. But a huge outfit like AirGas might have liability or certification concerns, since they supply hospitals, too.

    0
    n4mwd
    n4mwd

    Reply 5 days ago

    Maybe the best trick is to just not mention what its for.

    0
    ashtangakasha
    ashtangakasha

    Reply 4 days ago

    Ha! I tried that, but the guy guessed when he saw the tank. In any case, I do want only foodgrade, if one can trust them to honor the specs. I think AirGas would be reliable. I now have an official national account with AirGas, so I'll try to order a very small tank online. Anything would be cheaper than SodaStream.

    0
    XlaitsX
    XlaitsX

    Reply 4 days ago

    Except that they have that "return a CO2 bottle, get a CO2 bottle" thing at Bed, Bath, & Beyond, right? Or did they stop doing that?

    0
    ashtangakasha
    ashtangakasha

    Reply 3 days ago

    I don't know. I'm far from any BB&B stores! I can exchange SodaStream tanklets at WalMart, but they're just as obscenely expensive as anywhere else.

    0
    takeme2theriver
    takeme2theriver

    3 days ago

    Loved you idea. One thought, though. If the regulator gets knocked off it will behave like a rocket, not a missile. Missiles have a guidance system. Rockets just go kind of where they are pointed. 🙀

    0
    goldenskyhook
    goldenskyhook

    7 days ago

    I've had a similar setup for years. I have never had any problem getting my gas from a welding supply shop, BTW.
    I use two 5 lb. tanks, because I'm not able to do a lot of lifting. One thing I discovered, however, is that the newer sodastream machines (the ones that just clamp onto the pressure bottles, rather than having to screw them onto the valve) don't seem able to deal with the higher pressure from the large tanks. I went through THREE of them, before I broke down and bought a couple of older models off ebay.

    0
    XlaitsX
    XlaitsX

    Reply 4 days ago

    You could have bought a pressure regulator instead, and that would have reduced the pressure between the tank and the SodaStream.

    0
    n4mwd
    n4mwd

    4 days ago

    Just remember that no matter where you get your CO2 from, once its mixed with water, it reacts with copper to make a poison. That's why all the fittings and tubing need to be stainless steel or plastic.

    0
    dawndenver
    dawndenver

    7 days ago

    Get your Co2 from suppliers that serve the soft drink industry, it is food grade and safe. Do Not use industrial-grade Co2. It may contain oil, which will interfear with the carconation process, as well as tracses of other gases. Even using high quility industrial gasses I had one case wrere there was a trace quanity of a poision gas, it was in very small quanity.

    0
    DouglasB93
    DouglasB93

    Reply 7 days ago

    CO2 may be different. But I know my local welding gas supplier also supplies medical oxygen. Both medical and welding oxygen come from the same supply tank and are sold for the same price.

    0
    dawndenver
    dawndenver

    Reply 6 days ago

    When getting oxygen at the industrial dealer's I always received gas that was the medical grade. I don't know if that would be te case in all tank sizes.Note oxygen tanks have a different fitting than other tanks, Don.t want to mix with a fule gas. Other gasses come with many variations, such as oil-free. Industrial grade CO2 may contain oil, and can not be used with artist airbrushes or carbonate water. When using industrial gases you can run into the different fittings on the tank, i have had that happen with some special gas mixtures. The best sources for food-grade CO2 are Suppliers to restaurants and bars, having confidence in the quality and fitness of purpose.

    0
    Vandy BethG
    Vandy BethG

    7 days ago

    Doesn't this system unnecessarily contribute to greenhouse gases in the atmosphere?

    0
    gcai_fwb
    gcai_fwb

    Reply 6 days ago

    If you feel that this would be a major contributor of greenhouse gases best you stop drinking draft beer and convince the rest of the world while you're at it - good luck!

    0
    Vandy BethG
    Vandy BethG

    Reply 6 days ago

    I never used the word "major." I said "unnecessary."