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

by | Kitchen

Do you have a SodaStream machine at home and wish you didn’t have to pay for the expensive CO₂ cylinders every time they run out? Well, you’re in luck! In this article, you will learn how to refill your SodaStream gas cylinders at home using a simple adapter. We will break down the refilling process step-by-step, including the tools and accessories you will need for the job. Furthermore, we will talk about the different types of threads used to connect the SodaStream cylinder to a large standard CO₂ cylinder and the precautions you need to take when working with CO₂ cylinders. Finally, we will give some tips on where to buy CO₂ and how to store it.

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

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)
  • 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:

Step 1

Place the gasket in the connector of the SodaStream filling adapter (here is an Amazon link to the one we use) and screw it onto the valve of the large CO₂ tank. With a wrench, tighten the connection until it is snug. Ensure both adapter valves are in the closed (90°) position.

How to Refill SodaStream Cylinder STEP 1

Step 2

Screw the SodaStream cylinder onto the pin knob connector (ensure the pin is unscrewed). Now screw in the pin knob to open up the SodaStream cylinder valve.

How to Refill SodaStream Cylinder STEP 2

Step 3

Open the on/off valve so it’s aligned horizontally with the adapter’s tube. Leave the second (release) valve closed! Now we are ready to start filling.

How to Refill SodaStream Cylinder STEP 3

Step 4

IMPORTANT: With a slight twist, gently unscrew the valve on the large CO₂ tank until you start to hear a slight hissing noise. It is critical to increase the pressure slowly and gradually since a sudden increase in pressure will stop the flow of CO₂ to the recipient cylinder (Need a quick fix? Click here).

Step 5

Allow the CO₂ to fill the SodaStream cylinder for at least 1-2 minutes, then close the large CO₂ tank valve. To reach its full capacity, you need the recipient cylinder to be freezing cold.

How to Refill SodaStream Cylinder STEPS 4 AND 5

Step 6

Unscrew the pin knob connector to its original position.

How to Refill SodaStream Cylinder STEP 6

Step 7

Slowly open the release valve to relieve any remaining pressure in the system and then close it again. It may be loud!

How to Refill SodaStream Cylinder STEP 7

Step 8

Close the on/off valve on the adapter and unscrew the SodaStream cylinder from the adapter. Done!

How to Refill SodaStream Cylinder STEP 8
There you have it! You’ve now saved some money and can enjoy an almost endless supply of seltzer water without harming the environment. Enjoy!

Common Issues When Refilling SodaStream Cylinders

The Flow of CO₂ Has Stopped

If you have a SodaStream cylinder with a valve that has a wide pin in the middle, make sure to open the valve of the large tank very slowly. A sudden increase in pressure will stop the flow of CO₂ to the recipient cylinder. If this happens, you will need to release the built-up pressure in the filling system.

Old Narrow Pin vs. New Wide Pin
To release the pressure:

  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.
  • 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.
Large CO2 Tank Placement 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.

Residual Pressure Valves (RPVs) vs Standard Valve

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!

Cumulative Costs of Original SodaStream Refills vs. Home Refills
Annual Costs of CO2 Refills

Below, we have created a table with cost-saving calculations so you can check how much you can save with your CO₂ consumption if you use the 10 lb CO₂ tank – Amazon link.

How Much You Can Save Refilling SodaStream Cylinder at Home
Cumulative Savings with Home Refills

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.

LARGE CYLINDER SIZE LARGE CYLINDER REFILL TO START SAVING COST OF 60 LB OF CO₂ REFILLS SAVINGS ON SODASTREAM REFILLS AMAZON LINK TO CO₂ CYLINDER
2.5 lb 4th $468 $536 Link
   5 lb 2nd $340 $665 Link
 10 lb 2nd $326 $679 Link
 15 lb  1st $305 $699 Link
 20 lb 1st $321 $683 Link

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.

Large Cylinders

SIZE AVG. EMPTY CYLINDER COST (w/ accs.) AVG. REFILL/ EXCHANGE COST EQUIVALENT NO. OF SODASTREAM CYLINDERS
2.5 lb $107 $15   2.8
   5 lb $113 $19   5.5
 10 lb $180 $24 11.0
 15 lb $191 $28 16.6
 20 lb $220 $34 22.1

SodaStream Cylinder

SIZE 1ST NEW FULL CYLINDER COST EXCHANGE COST
0.90625 lb $29.99 $14.99

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.

We hope you found this guide helpful! If you have any questions or tips, please feel free to share them in the comments section.

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