Cheaper Sodastream With A Big CO2 Tank Is A Semi-Dangerous Way To Save

Sodastream machines are a fun way to turn tap water into carbonated water. However, the canisters are expensive and generally require a trip to the store to get a replacement. Lifehacker has a workaround that may make life easier for the bubble-addicted set.

The trick is simple: simply buy a larger bottle of CO2, and hook it up to the Sodastream in place of the regular cartridge. CO2 can be bought in large cylinders at a far cheaper rate than Sodastream will charge you for their proprietary canisters. All you need is a local supplier of food-grade CO2 in cylinders, and you can visit them when you need a refill or swap.

There are several caveats, though, which the comment section dicussed when we featured a similar hack before. Getting an extra-large CO2 canister can pose a risk to life if there’s a leak. Alarms may not save you as the heavy gas has a tendency to lurk low to the ground. You should also consider using a regulator to lower the pressure from your large canister to something closer to the levels the Sodastream machine is built to withstand. Beyond that, you want to ensure you’re using food-grade CO2. Don’t go bubbling cheap welding gas through your water if you want to live a long and healthy life.

It’s a neat hack, it’s just one that requires you to practice proper gas safety at all times. Reports are that a cylinder costing less than $200 can last you for several years though, with ultra-cheap refills, so it may indeed be worth the hassle! Go forth and bubble, friends.

69 thoughts on “Cheaper Sodastream With A Big CO2 Tank Is A Semi-Dangerous Way To Save

  1. Eh. I have a $50 adapter and a $180 siphon-tube 20lb tank in the garage. I drink enough soda water to go through a CO2 tank at least twice a year. I just refill the 1lb bottles with the adapter. That sodastream charges $20 for the little 1lb tanks is bonkers. You pay less for cans of soda (even with the deposit) after flavoring. Refilling your own or hooking up a tank like this, you’re going to be saving a buttton of money by comparison. The 20lb tank costs me ~$30 I think to refill/exchange.

    If you have a leak from a 20lb co2 tank that is large enough to suffocate you in any normal house, you’re going hear it.

    1. Similar here. Siphon tank in the basement with an adapter which is used to refill the standard SodaStream cartridges. No one lives in the basement, so no worries from a leak. The tanks lasts for 1-2 years, and i revisit the local airgas once in a blue moon to refill the big tank with food grade CO2.

      1. ” No one lives in the basement, so no worries from a leak. ”

        Homeless person says hi. :-)

        How about a used soda machine from a business? The tanks themselves were pretty sturdy and the syrup came in gallon sized jugs.

        1. Being hopelessly addicted to carbonated water, that sounds amazing. Unfortunately, soda fountains/guns use motorized carbonators, something that’s going to run you at least $200 – that’s assuming you get a used one for cheap and it doesn’t need an overhaul. Those chillers are kind of a maintenance headache as experience serves me. You’ll also need something to chill the water before it hits the carbonator or else you’ll be serving 95% flat soda water – just carbonated enough to taste weird. Chillers like these cost a small fortune to run, or you need a tub that’s full of ice all the time that cools the water like they have at bars.

          1. I used to have a Multiplex Meteor II, the final model of soda fountain that was custom designed for a company (Coca Cola). The later machines have all been common designs with replaceable brand panels.

            The Meteor II had three syrup tanks, expanded from two tanks on the Meteor, so that in one machine a restaurant could have Coke, Root Beer, and Orange Fanta.

            It was made to be filled with ice to chill the syrup (which was poured into three rectangular plastic tanks with loosely fitting lids) and the ‘cold plate’ which had the channels the carbonated water flowed through on its way to the nozzles.

            I also had a Jet Spray cooler that functioned. I thought about building a cart with a carbonator and the Jet Spray in the bottom, modifying its magnetic drive pump to circulate water up to the ice tank of the fountain then have it drain back to the Jet Spray’s tank.

            The major stopping point was the carbonator. Those things are bleeping expensive, even used or second hand.

            At the time, none of the Coca Cola collectors books included the Meteor II (late 1990’s) and information online about it was pretty much nonexistent. No idea why since the model dated to the late 1960’s, having been superseded by the generic machines in the early to mid 1970’s. Just did a google on it and there’s still little info on the model, and the very first hit is wrong, it says the Meteor II is a two flavor fountain.

            I did get a photocopy of the manual and parts diagram + list for free from Multiplex, who assured me it would still be legal to use in a commercial restaurant. “Does it still have the NSF label on it?” I said it does so they replied it’s OK to use.

            So I ended up selling the Meteor II and both Jet Spray coolers I had for more than I paid. The buyer said he was decorating his kitchen like a soda shoppe with a Coke theme and the fountain would be installed on the counter to dispense Coke. He did remark on the almost total lack of info on it in the books and online.

    2. You can make a nice carbonated ginger-ale using nothing but chopped up ginger and brewers yeast. You can find recipes online. I used those German (Grolsch?) style bottles with the latching stopper on the top. With the right recipe and a few days of brewing, you get a nice carbonated drink with no need for CO2 bottles, regulators etc.

    3. I like simple solutions. I’m a simple guy.
      The wife bought a sodastream. I objected to the $1US per 30gm (1oz freedom unit) and bought a regulator, two 10kg and a 25kg bottle at auction of a defunct McDonald’s for (I think) $50US. I gave the 25kg to my local CO2 supplier (they do fast food, welding and fire extinguishers) as it was just too much. I’m now being charged $4US per kg for my CO2.
      I use a carbonating cap I made with some CPC fittings (they make really nice fittings) and carbonate by pressurizing ~2.5 bar and shaking the bottle until the bubbles pretty much stop coming out of the tubing. It works well. I also bought a setup to refill the (old) sodastream bottles for another ~$50US online. The wife still uses the sodastream. I keep an eye out for the old bottles as the company has sabotaged the new ones somehow. I plan to sabotage their sabotage when I find a new bottle to disassemble and figure out how it works.
      As an anecdote, I was almost done in by CO2 inhalation about 50 years ago when I was working as a lab tech in a university biochemistry lab. They had a chest freezer in the basement tunnels used to store dry ice. I was tasked to get some and, because the chest was nearly empty I had to lean in to get the material at the bottom. I started to black out and fell back outside of the freezer. Had I fallen in instead, I doubt my absence would have been noticed until waaaay too late. Good times.

    4. The Primo was so much better than the soda stream. It just used a normal tank thats used for paint ball. You could just get the tank refilled cheap. Too bad it got discontinued.

  2. You have to have a way to fill a suitable container and you have to be sure it’s safe just like with bottled gases, but an easier way to get the same CO2 is dry ice at a grocery store. You can buy just a small amount at a time for a few dollars and take it home in a foam box.
    It’s putting it into a suitable container that can hold the pressure which is the harder part if you don’t pay airgas to do it for you. If you put too much dry ice in the tank and walk away, it can burst. But if you put the right amount into a tank that started clean with only air in it, and you allow excess pressure to vent through a safety valve of sufficient size, then you will end up purging most of the air along with a bit of the wasted co2. Otherwise you could choose to underestimate the amount of co2 needed, accept that there will be some air left in it or that you won’t use the tank up fully, but better avoid reaching the maximum pressure of your tank at any point.

    1. (If you don’t have a problem with larger tanks that’s much less of a production with very little to go wrong compared to this way – but if you are, this is a way to get very small amounts of co2 rather than keep much around if you’re worried about it.)

    2. The ready availability of dry ice is a bit of an American thing I think. At least here in NZ the only way you can get dry ice is from industrial suppliers, of which there are 1 or 2 in the entire country. It’s not sold in retail stores.

      1. Here is New Jersey, USA I haven’t seen dry ice in retail stores either. Aside from industrial suppliers I’ve only seen it sold in one camping supply store.

        1. The only other place I remember getting some from is when there’s a delivery shipped in dry ice and there’s some left over. In NJ you probably can either get a bottle delivered or get a bar to fill you up, although they may or may not have ‘beer gas’ instead.

        2. Here on a planet called Florida where we are trying to protect our children from really scary school teachers, Publix supermarkets sells bags of dry ice straight out of a cooler inside the store.

    3. You’d be hard pressed to put too much dry ice in the tank. It’s frozen as a powder and pressed together, making the density far lower than liquid CO2. If you tried to completely fill the tank with dry ice, by the time it melts it will have far more headroom than a bottle filled with liquid.

      The only way you’ll overpressure the canister is if you get it too hot, but it’ll blow the release valve, instead of bursting.

      1. Hmm, a quick search says bulk density about 1 depending on how well pressed, where liquid is 1.1 or so. I guess I misremembered thinking they compressed it closer to the ideal density for at least some formats.

      2. I concur! I’ve been unable to fit more than about 550g of powdered dry ice in a 60L tank (410g tankl). I usually shoot for about 510g. Enough to make the effort worthwhile and the Soda Stream device capable of pressing the release valve to allow carbonation.

        I’ve been refilling this way for years. 5-6 tanks for $30 of retail (grocery store) dry ice. I’ve had multiple burst discs fail, allowing the tank to slowly depressurize. When you examine how thin those burst discs are, you stop worrying about tank failure.

    4. It’s fairly easy to refill a Soda Stream tank with dry ice. They hold 14.5 ounces of CO2. Unscrew the valve from the tank, unscrew the pressure vent just enough to open it. Put 14.5 ounces of dry ice into the tank. Screw the valve back in and wait until you hear gas coming out of the vent. That signals the sublimating dry ice has built up pressure. Give it a couple of seconds venting to push out the air then close the vent.

      Leave the tank to warm up to room temperature. It cannot over-pressure because 14.5oz of CO2 is 14.5oz of CO2 no matter if it’s solid, liquid, or gas phase.

      The hardest part of this refill procedure is getting the chunks of dry ice into the fairly small neck of the tank, and how much you’ll lose to sublimation to CO2 gas before you get 14.5oz into the tank.

      1. If you can load directly into one of theirs, that sounds a lot better; I have been worried that I made it sound like building a high pressure tank is no big deal, and that’s why I tried to be vague. I would probably buy a block of dry ice, put it in a nearly airtight bag (except for something for the co2 to vent from), and hammer it to powder, then cut the corner to funnel it into the opening. Hopefully minimal moisture contamination that way, although the density won’t be great.

      2. Use two nested 1 Gallon Ziplock bags, a dollar-store rubber mallet, a dollar-store funnel, and a chopstick to pack the powder thru the funnel. I like to use a kitchen scale to take an empty tank weight and then fill to no more than 510g. Any more than that and the Soda Stream’s carbonator is not able to press the release valve to allow carbonation.

      3. A wide funnel and a metal skewer work beautifully for agitating/poking the pellets into the cylinder.

        As for loss to sublimation, don’t weigh the dry ice first, weigh it after its in the cylinder. Just place the empty cylinder with the valve removed on your kitchen scales and tare them. Then add some dry ice and weigh the cylinder, repeat as necessary until you hit ~450g.

        As an extra step to make sure there are no leaks and to aid in melting, fill your sink with room temp water and submerge the cylinders after you fill them. No bubbles, no leaks and the cylinders are ready to use in 5 minutes.

    5. Please, no one do this, it is a terrible idea. If you don’t understand why it is a terrible idea, then it is even less safe for you to do it.

      It is irresponsible to suggest this, from pressure vessel safety to high risk of contamination and dry ice not being regulated the same for purity as food or bev grade tanks.

      Get a real tank, 5lb if you want a smaller amount, and proper hoses and regulators. If you want a bigger tank, get a CO2 alarm. Keep them in a reasonably ventilated area.

      (PSA: The more you know! . . . 🌠)

      1. Much like instructions for making sushi would ask for sushi-grade ingredients and clean kitchenware and such to prevent food poisoning, by requiring things be safe rather than specifying what is safe, I make sure anyone who isn’t a fool will stop when they realize they don’t know how to tell if something is safe or suitable.

  3. When you can get soda stream bottles refilled (exchanged for a full bottle) for less than €2 then getting a large bottle isn’t worth the hassle (especially when even just the cost of refilling is more expensive per gram for a larger bottle than swapping out a sodastream). Combined with the fact if you own a larger bottle you need to pay for it’s re-certification and pressure testing.

    Yes the CO2 market in Sweden is rather topsy-turvy compared to the rest of the world :)

    1. As a nation proficient in creating workarounds for any kinda if laws we created (aka Poles) our filling companies don’t sell pressure canisters, they rent them. Free of charge, just the cost of gas , but all the paperwork and cerrification stays with them. Neat! And actually safer, since companies will do testing while individuals (or small companies) most probably would “forget” about that little detail

  4. I have done this with a Aquarium device that used CO2 from Soda stream tubes to give more CO2 to the plants in the aquarium. It was expensive, so I bought a real full CO2 tube, that is used for tig and industry size (that is about 1 m high tubes). Much better price.

    So, a friendly supplier of CO2 (for fire extinguisher) took an old Soda stream tube, cut the gas connection off and silver soldered it to a ordinary CO2 tube connection. Worked great, until we was going to test it. The pressure was WAY to high, so CO2 device almost exploded when we open the gas tube.
    We needed to also cut the gas pressure REGULATOR from the Soda Stream tube and added it to our adjustment.

    After that adjustment, it still work to add CO2 to my Aquarium plants, so they grow with high speed. :-)

  5. 1) there are commercial adapters that let you refill your proper sodastream bottles easily from a larger tank
    2) same company makes replacement sodastream bottles designed to be much easier to refill and sell for same price as a new sodastream bottle
    3) compressed CO2 is a liquid (well, a weird liquid-gas state according to the triple point diagram but bear with me) so the pressure is going to be the same no matter how full it is until the very end. So I don’t understand how the pressure from a 5lb (or any other size) CO2 cylinder is any higher than the OEM bottles that also must contain liquid CO2. Maybe I’m missing something. It is roughly 700 PSI at room temperature, so I assume the sodastream machine has a tiny orifice or some other passive regulator system in place. Which should be effective regardless of where the CO2 is coming from.
    4) I get my CO2 cylinders for beer use from the welding supply- they are everywhere and are food grade and stuff, refill, what, like $20 for a 5lb cylinder?
    5) plumbing in (instead of just refilling) seems even easier yet, I love this idea.

    1. I’m using a 5 pound tank that connects to the machine via a reinforced hose. Crack valve, carbonate until the SS’s pressure relief burps, close valve, carbonate to release pressure. Roughly $25 for rank refill, though there was a significant investment setting up.

      It’s not _that_ much bigger a CO2 tank than SodaStream’s. About 2.5x the size of the original larger tank that they stopped offering. While I grant that there’s a safety concern, I think knowing that one must be careful with the tank may get more of an issue than the gas, at least as I use it.

      For I while I was dealing with a brewing supply store, which did the “tank rental” thing. I do like that approach, even if it costs a bit more, if it’s really undergoing a full test every time. But they went out of business and let me keep the tank, so…

      They, and every other homebrewer I’ve spoken to, believed that welding supply companies were buying their CO2 from the same places lab supply houses did, and that despite not being handled as foodstuff or ideal chemical it was almost certainly Pure Enough. I suppose we could ask a college student to do a spectrographic analysis, but given the number of colleges in Boston I would guess someone around here already did so and we’d have heard if the results were problematic.

      1. A CO2 tank for use in welding or especially for a CO2 LASER that had contaminants in it like oil would not be good for those uses. Oil vapor could contaminate the welds and I bet it would really foul up optics in a LASER.

        Gas impurities like a little oxygen or nitrogen or the various trace gasses in air may not bother welding or LASER use and we breathe them in and out without dying horribly and quickly, so I suspect some of them in our soft drinks wouldn’t be a bother.

        The only reason I can see for “food grade” labeling or certification on CO2 is to ensure it’s 100% pure carbon dioxide. Or does it have a % of allowable non-toxic other gasses?

        Could be that CO2 for industrial use that must absolutely be 100% pure is better than “food grade”?

        1. Food grade means that the machinery that handled it is cleaned to specifications. The CO2 is the same, but it’s not been allowed to run through a dirty pipe before you get it.

  6. All CO2 comes from the same source, there is no specific food grade CO2. Same thing with other gasses like medical oxygen, comes out of the same dewar as the rest of the oxygen, though they do have purity monitors on the lines to make sure there are no contaminants. (I worked in a fill plant)
    The pressure in one of those little cylinders is the same as in a big one, about 750PSI
    People use large CO2 bottles on aquarium systems an people aren’t keeling over from CO2 leaks. At least high CO2 levels will cause a physiological reaction unlike other gasses.

    1. And the funny part is that the purity requirements for welding gasses (O2, CO2) is higher than for most other use cases. This doesn’t mean that meeting the standard for welding gas will make it meet the standard for food or medical, though. Different paperwork and monitoring.

    2. These Sodastream things look really flimsy. In Argentina we have these automatic stainless steel carbonators (sifón Drago), they can outlive you easily and don’t require much care other than an o-ring replacement every half a decade. plus the CO2 refill network is huge, you can replace your tube in a hardware store for $2, lasts 40 refills on the 1.5L model. and a new set (1.5l + one tube) costs about the same as a Sodastream. which is a bunch of plastic parts. Seems like they want to get your money from the initial product AND the subscription

          1. Makes sense, we still call them that way here because of the tap system. I love it, can’t imagine using a soda bottle with screw cap… you need to drink it all in one go or it goes flat

            A friend uses the Drago tube and a regulator to carbonate craft beer. it’s not terribly expensive at ~$2 per 350g. Some people even use the actual “syphon” for beer

    3. It’s not actually the gas that makes the difference in food grade or not, it’s the cylinders for the users. Food grade has to be cleaned (and certified, always paperwork involved), but the welding ones can have oils from manufacturing still in the tanks.

    1. CO2 is not as dangerous as other asphyxiant gasses as your body is specifically tuned to detect it. In fact when you feel puffed / short of breath, that’s because your body detects excess CO2, not the lack of oxygen. If you went into a room with CO2 you would immediately feel uncomfortable and leave. You’d have to be be very determined, or forced against your will in order to suffer harm.

      Your body cant detect nitrogen and you could hang around in a cloud of it, feeling quite OK until a few moments before you pass out. You also cant detect Carbon Monoxide and it binds to your blood, making you feel sick even at low concentrations. If you realise what it is and manage to get out, you’ll still be poisoned.

  7. I use a 20 lb tank with my Sodastream using a Chinese hose and adapter. I recommend closing the valve on the tank after carbonating water. Then you don’t have to trust a cheap adapter or the integrity of plastic valves in the Sodastream not to asphyxiate you and everyone you hold dear.

  8. I’m generally a proponent of skipping the sodastream altogether and just using standard soda and beer equipment. For about the same as getting a big tank and a sodastream you can get the tank and a regulator, hosing and connectors, and a carbonation cap for a soda bottle which allows you to carbonate anything, at a set pressure vs the guesswork of shooting pure unregulated CO2 into a bottle of sodastream.
    There are a ton of new products for homebrewers that work just as well for soda or other carbonated drinks that really bring the barrier of entry down, like plastic kegs or just tee adapters that let you use standard soda bottles as kegs.
    Then you’re already set to upgrade if you want to and can easily have continuous soda water on tap if you get a fridge, a keg, tap of choice and a water refill lid. The former two are often available cheap on the used market.

    1. I’ve had soda water on tap in my converted -freezer kegerator for years; refilling the keg is always a pain and I end up out of seltzer for a few days, even with switching between two kegs.

      What is this water refill lid you speak of?

  9. if you are going to swing for the co2 tank, you might as well spend 20 bucks on a used corny keg. you usually spend more on fittings than the rest of the system. get an old cube freezer or mini fridge, you probibly have space for a couple kegs and taps. and of course im gonna do the og coca cola recipe, complete with special ingredients.

  10. Follow up. I’m a huge home brewer with full keg set up.
    Nothing more baller than a whole keg of carbonated cocktails.
    It’s also easy to make a whole keg of carbonated water on draft but somehow I’m too lazy to go to garage for a glass of water so we still use a Sodastream on the counter.

  11. I used to get paintball tanks refilled for $3 at the local sporting goods place, then used an adapter off ebay to install it into a standard Soda-Stream dispenser. Worked great, but then the Sporting goods store went out of business.

  12. You can’ beat physics of dense gas collecting in the low spots, but i wouldn’t be repelled by the risks associated. Note that many restaurants and beer pubs use these to propel the soda/beer taps and deadly accidents are yet to be heard of. HORECA (HOtels, REstaurants, CAfes) distribution would be also my primary choice for sourcing the gas product, to make sure i’m getting food grade.

  13. Can flat soda in a screw cap plastic bottle be recarbonated by dropping in a pellet of dry ice then screwing the lid on? How much dry ice is too much for this?

    1. Yes. You can recarbonate most things semi-indefinately. Stuff like beer or pH sensitive liquids won’t be the same after recarbonating but the’ll recarbonate just fine. Beer has proteins that get folded & tangled so shaking or recarbonating will affect head retention.
      You can buy plastic or stainless steel caps for soda bottles that have ball or pin lock keg connections so you can carbonate 2L at a time.
      Be careful because there are 2-3 ‘standard’ soda bottle thread types and they aren’t all intercompatible.

    2. You might want to look into the “fizz giz” system. It uses soda caps with what is essentially a silicone version of the kind of air valve used for inflated balls. In my opinion it is an absolutely brilliant concept that avoids the need for a large soda bottle like the soda stream uses. It also gets around the SS contamination issue: you can carbonate anything without having to worry about contaminating the carbonation tube. Just wash the cap and reuse. I’ve used it to re-carbonate opened soda bottles and to make flavored carbonated beverages as well as single-bottle soda water.

      Googling the term finds many different suppliers of just the caps and for handheld CO2 “banana” injectors. There are 2 types of injectors: one uses small CO2 cartridges (handy, but the cartridges get expensive). The other “soda rope” style replaces the cartridge with a regulator and hose setup (more expensive upfront, but allows cheaper bulk CO2 tanks). Or you can make your own. I’ve used just a regulator, hose, and air nozzle. Anything that can seal against the vale top will work.

      A few things to keep in mind:
      – Chill the container back down before re-carbonating.
      – purge the air from the container. For a plastic bottle you can just squeeze it until there is no air space before putting the cap on. For a glass bottle, put the cap on loosely and shoot some CO2 into it to force out most the air.
      – always a risk of the bottle rupturing (hasn’t happened to me yet). At least wrap a towel around the bottle when pressurizing.
      – I don’t know if it really helps, but I pressurize with the bottle upside down. I think it helps to force the gas to bubble through the liquid.
      – As the gas dissolves into the liquid, the pressure will drop. You can “top off” the pressure, keep doing this until it won’t take any more gas. You can build up a really fizzy drink this way.

      My normal re-carbonating cycle:
      – purge the container, for both plastic and glass I do the “loose cap purge” method
      – chill down in the fridge (let it get as cold as possible) .
      – purge again, then re-pressurize
      – shake the bottle
      – later, “top off” the pressure.

      1. Seconding the Fizz Gizz. This was the magic bullet for me. You do have to get used to using it- you can shake the bottle a lot harder than you think—you will noticeably feel the pressure in the bottle decrease as the CO2 dissolves if you are shaking it hard enough.

  14. I spent a long time looking for Sodastream alternatives, and finally found this: http://www.fizzgiz.com/index.htm

    This has been the best solution for me, because it’s easier to get these small cartridges by mail, so you don’t have to go and get canister refills, nor do you have to get heavy cans or bottles of seltzer shipped to you, and you generate minimal waste (just the cartridges themselves, which are steel and can be recycled).

  15. Before Sodastream existed, I had a kegerator. When I had fewer than three beers full, I’d fill the extra tank with water. Seltzer on tap. Good times.

    Cornelius kegs, regulator, a tap, and you can get the gas at the gas place. Done! Oh, and a metal-cutting hole drill set to drill through the fridge. :)

  16. Visit a home-brew shop for all the gear. CO2 tanks, lines, regulators, adapters, and refills.

    I’ve not made homebrew for a while but I’ve still got all the gear. You can force-carbonate a beer keg using Sodastream cartridges, and they’re about half-price to refill at the homebrew shop as opposed to the traditional swap at the supermarket – AUD$10 vs AUD$21.

  17. I got part way through the comments, realized nerds overthink everything. I have had my own regulator attached to a co2 container for more than 7 years. Buy the stainless steel adapter for 2 liter plastic bottles. The agitation comes from you shaking it up a bit by hand, or put it on a vibrating table or some such if you are lazy. Can have enough for a few days in a matter of minutes, and always shut the valve off when done. Cost me around 100 bucks for all the parts on amazon back then. If you are super worried about a leak, get a vaccum storage bag for it. Extra hassle, but you woud visibly be able to see a leak as the bag would blow up like a balloon.

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