How to Refill Your SodaStream CO2 Cylinders at Home: A Complete Guide

Follow our guide, and you should be refilling your own cylinders in no time!

Important Things to Know Before Purchasing a SodaStream Adapter

Having gallons of seltzer water for pennies on the dollar sounds great in theory, but there are a couple of important things you should consider before purchasing a SodaStream adapter and a CO₂ tank, so you don’t end up with a useless piece of accessory.

Here are the most important things to consider

• Do you have a place where you can refill the large CO₂ tank?
• What thread does the large CO₂ tank valve have?
• What thread does your SodaStream CO₂ cylinder have?
• Is there an RPV valve on the CO₂ tank you’re considering?

Also, if you plan to purchase a larger (10+ pound capacity) CO₂ tank, it’s best to look for ones with a dip tube. This allows an easier refilling of the SodaStream cylinder without the need to turn the large tank upside down.

If you have considered all of the above and have all the necessary parts, you are ready to purchase an adapter and make your own CO₂ refilling station!

If you are unsure about any of the above questions, click on the relevant link for more information.

Precautions When Working with CO₂

• CO₂ is an asphyxiant and can displace the oxygen in a room, so it is important to store it in a well-ventilated area. In case of a leak, the concentration of as little as 10% of CO₂ in the room can lead to coma and death.
• CO₂ tanks are under high pressure and can explode if damaged. Handle with care!
• Do not store CO₂ tanks near heat sources, such as stoves or radiators. The maximum storing temperature should not exceed 120°F (49°C).
• Make sure the valve on your CO₂ tank is closed when you are not using it.

Tools and Parts Needed for Your SodaStream Refill Station

Make sure you have the correct thread types on all the parts you need for the job.

• Full large donor CO₂ cylinder (US CGA 320 valve, EU+AU W21.8-14)
• Empty SodaStream CO₂ cylinder (US+EU TR21-4 thread, AU+NZ G1/2 thread)
• SodaStream adapter (choose an adapter with the right threads for both the SodaStream cylinder and the large CO₂ tank, e.g., CGA 320 + TR21-4 thread – the most common in the US and the one we use – Amazon link)
• Wrench (to tighten the adapter)
• Safety glasses and gloves (make sure to wear them when working with CO₂)

How to Refill Your SodaStream Cylinders: Step by Step Instructions

To achieve optimal filling, it is recommended to put the SodaStream cylinder in the freezer for at least an hour before starting the filling process. Liquid CO₂ tends to expand with heat, so we want the cylinder to be as cold as possible. Keep in mind that if your CO₂ tank does not have a dip tube, you will need to hold the tank upside down during the filling process or lay it on its side if you have a larger capacity tank.

To refill your SodaStream cylinder at home:

How to Refill Your CO2 Cylinder For Soda Maker – Video Guide

Common Issues When Refilling SodaStream Cylinders

1. Close the main valve on the donor CO₂ tank.
2. Unscrew the pin knob connector to its original position.
3. Slowly open the release valve on the adapter to relieve the pressure, and close when done.

You can now try filling your SodaStream cylinder again.

The SodaStream Cylinder is Filled Only Partially

• To refill the SodaStream cylinder completely, it has to be as cold as possible. We recommend putting it in the freezer for at least an hour before starting the filling process.
• It can take approximately 1-2 minutes to reach its full capacity. If you want to track the progress, we highly recommend weighing the small cylinder on a food scale during the filling process.
• As the large CO₂ tank empties, the pressure inside will drop, making filling the smaller bottle increasingly difficult. With a 10 lb tank, this is when you have around 2 lb of CO₂ left in the bottle. You can still partially fill the smaller cylinder, but it will require repeated refreezing to reduce the internal pressure. For this reason, we recommend purchasing a larger tank to minimize losses of unused CO₂.
• If you have a large CO₂ tank without a dip tube, lay it on its side, e.g., on a mattress, to allow the liquid CO₂ to flow into the recipient cylinder. Liquid CO₂ tends to keep at the bottom of the bottle; that’s why we need to keep it at an angle during the filling process.

The SodaStream Cylinder is Not Filling Up

Check whether your large CO₂ tank has an RPV valve (what is RPV valve?). If it does, you will need to purchase an adapter that allows you to bypass the RPV valve.

Do You Have a Place Where You Can Refill the Large CO₂ Tank?

When considering making your own SodaStream CO₂ refill station at home, the first thing you need to think about is whether or not you have a place where you can refill the large CO₂ tank. From my experience, this might be more difficult than you expect. For example, certain places may require you to use their CO₂ tanks and offer a limited variety of sizes, which can be more costly. Others may sell exclusively to companies, and some places might not have a suitable food grade or beverage grade CO₂, etc. So, before you purchase a SodaStream adapter and CO₂ tank, make sure you have a place where you can refill it.

Where Can You Refill Your CO₂ Cylinder Tank?

There are a couple of places where you can get CO₂ for your large tank. The best place to ask is at your local homebrewing store. If you don’t have a homebrewing store nearby, you can also try your local fire defense or welding supply shop. They typically have CO₂ in various sizes and purities, but you’ll want to make sure to get food-grade CO₂ or, even better, Beverage Grade. If you are wondering why welding shops can offer food-grade CO₂, it is because, for welding, you don’t want any impurities in the CO₂. This would have a detrimental effect on the quality of the welds and the welding machine itself.

Some other places where you can look are:

• Fire Extinguisher Refill Shops (Fire Defense)
• Commercial Gas Vendors (AirGas, Robert’s Oxygen, Praxair/Linde, etc.)
• Paintball Stores
• Aquarium Supply Stores
• Hydroponic Stores
• Home Pub & Brew Supply Shops

What Thread Type Does Your CO₂ Tank Valve Have?

An important thing you need to do is identify the thread type of your large CO₂ tanks valve. The most common type sold in the US is a CGA 320 valve. The most common type in European and Australian markets is a valve with a W21.8-14 (DIN 477) thread and sometimes a less common G3/4.

If you purchased your CO2 tank a while ago and are unsure about the thread type, the best way to find out is to look up your specific CO₂ tank online or contact the manufacturer.

What Thread is a SodaStream CO₂ Gas Cylinder? Do All SodaStream Cylinders Use the Same Thread?

SodaStream CO₂ cylinders sold in North and South America, Europe, and Asia use the same TR21-4 thread. However, in some countries like Australia and New Zealand, a different G1/2 thread is used.

Isn’t it Better to Connect the SodaStream Machine Straight to the Large CO₂ Tank?

While connecting your SodaStream machine directly to the large CO₂ tank might be more convenient, we do not recommend it from a safety standpoint. As we mentioned earlier, CO₂ is asphyxiant and can be dangerous or even lethal in case of a leak. For this reason, we recommend refilling your small SodaStream cylinders and keeping the large tank in a well-ventilated area away from your living space.

Be Aware of the Residual Pressure Valve (RPV)

Some CO₂ tanks have what’s called an RPV, or Residual Pressure Valve. An RPV is a small valve that fits inside the larger CGA 320 valve outlet. It often has a square, round, triangular, diamond-like, or another similarly shaped middle part of the valve. This valve prevents any potential contamination from inadvertently being backed into the cylinder. If you have an RPV valve on your CO₂ tank, you’ll need to remove it or get a special adapter with a pin that works with RPV valves. If you are looking for a suitable CO₂ cylinder, we recommend getting one without an RPV valve, as most refilling adaptors are not compatible with it. You can check out our list of the best CO₂ cylinders here.

How Much Does it Cost to Fill a SodaStream Bottle on Your Own? Is it Worth Refilling Your SodaStream Cylinder at Home?

Refilling SodaStream cylinders at home saves a lot of money. Let’s look at what kind of savings we are talking about. Assume you use two SodaStream Cylinders a month, hence 24 cylinders per year. In the first year, you can save 38% of what you would pay for the original SodaStream refills. This already accounts for the initial costs for the large CO₂ tank (10 lb) and accessories. In the following years, you save 85% of the annual costs. In five years, this makes $1370 in savings on refills – you save 76% of usual costs!

What Size CO₂ Tank Should You Buy?

Here is another look at savings thanks to refilling the SodaStream cylinders at home. You can see how much you can save using different sizes of CO₂ tanks with 60 lb CO₂ consumption. You will save the most money ($699) with the 15 lb tank. But this option might not be for you. Aside from the economic factor, you should also consider the size and weight of the tank. A larger CO₂ cylinder may yield a lower price per pound of CO₂, but it will be more difficult to move around, operate and store. Based on our research of economic and practical aspects, we have decided to purchase the 10 lb CO₂ cylinder – Amazon link, which gives us the best price to practicality ratio.

Cost of 60 lb of original SodaStream CO₂ refills is $1004.

If you are interested in the details of our calculations, below you can see the costs of different CO₂ cylinder sizes and the costs of the original SodaStream bottles that we have calculated with.

Note: The large CO₂ cylinders need to be tested for leaks and strength every five years. It is called hydrostatic testing and costs around $35. Every tank has a date stamp that indicates the due date for the next testing.