The first empty cylinder is the moment most soda maker owners in Thailand hit a wall. The machine was easy to buy, the water was good, and then the fizz stops and the question appears: where do you refill a soda CO2 cylinder here, and is it safe to do it yourself?
This guide answers that in practical terms. It explains what is actually inside the cylinder, why refilling it at home or at an industrial gas yard is a bad idea, what food grade means and why it matters for a drink, how an exchange works, and what a refill costs on our online shop.
In Thailand, the safe way to refill a soda CO2 cylinder is to exchange it: swap the empty for a full one at one of Minairal's four shops, or order online and return the empty by post. A 380 g food-grade refill costs ฿390 on our online shop and makes up to 50 litres. Do not refill it yourself.
What is inside a soda CO2 cylinder?
A soda cylinder holds carbon dioxide in liquid form under high pressure. The cylinders sold on our shop contain 380 g of gas, enough for up to 50 litres of sparkling water. When you press the lever on the machine, a valve opens, a short burst of gas enters the bottle, and part of it dissolves into the cold water as bubbles. Nothing else goes in: the cylinder adds CO2 and only CO2, which is why the quality of the gas matters.
The cylinder is a reusable pressure vessel. It has a date and a specification stamped on it, and it is designed to be filled by equipment that weighs the gas going in and checks the valve. That is the part a home user cannot replicate.
Can you refill a soda CO2 cylinder yourself?
You will find adapters online that connect a soda cylinder to a large industrial CO2 tank, and videos showing the transfer. We advise against it, for three reasons.
- Overfilling. A cylinder filled by weight to its rated capacity leaves room for the liquid to expand when it warms up. A cylinder filled by eye in a hot kitchen or a car boot in Thailand does not. Overfilled cylinders are the main cause of valve failures.
- Gas quality. Industrial CO2 is sold for welding, fire suppression and aquariums. It is not handled as a food ingredient, and the tank, the hose and the adapter are not either. Whatever is in them ends up in your glass.
- Valve and seal damage. The cylinder valve is designed to mate with the soda maker and with professional filling equipment. Improvised fittings wear it and can leave a slow leak, which you discover when the cylinder is empty a week later.
Exchanging the cylinder costs ฿390 and removes all three risks. The saving from doing it yourself is small, and the downside is a pressurised steel cylinder in your kitchen that nobody has checked.
What does food grade CO2 mean, and does it matter?
Food grade CO2 is carbon dioxide produced, purified and handled to the standards required for an ingredient in food and drink, with limits on moisture, oil and other contaminants, and with filling equipment kept for that purpose. Beverage CO2 is the same gas used in bottled soft drinks and in draught beer lines.
It matters because CO2 is the only thing you add to the water. If the water is clean and the gas is food grade, the sparkling water is clean. If the gas came from a tank that also serves a welding shop, you have no way of knowing. The refills on our shop are food grade, and the cylinder is swapped rather than topped up, so the filling is done on equipment made for it. Restaurants and bars use the same food-grade gas at larger volumes; see our drinking water systems for restaurants and bars.
How does a CO2 cylinder exchange work?
An exchange is the standard model for soda cylinders worldwide, and it is how our refill works. There are two ways to do it.
In person, swapped on the spot. Bring your empty cylinder to one of our four shops and leave with a full one: on Koh Samui at the Bo Phut showroom (151/35 Moo 1), in Phuket at Chalong, in Hua Hin at Hin Lek Fai, and on Koh Phangan at Thong Sala, at a point inside DELITALY. The Koh Samui, Phuket and Hua Hin pages give directions.
By post, from anywhere in Thailand.
- Order a CO2 cylinder refill on our online shop (฿390). The shop delivers across all of Thailand.
- Return the empty cylinder by post. The exchange requires an empty cylinder.
- Receive a refilled cylinder with 380 g of food-grade CO2, and screw it into the soda maker.
If you exchange by post, the empty cylinder leaves before the full one arrives, so many households keep a second one. An additional CO2 cylinder costs ฿890 on our shop, new and full, and means you are never without sparkling water while a refill is on its way.
Minairal cylinders are compatible with other major soda maker brands such as SodaStream, so the exchange works whichever machine you own. Unsure about an unusual model? Send us a photo of the cylinder. If you are still choosing a machine, our soda maker buying guide for Thai homes lists what to check.
How much does a CO2 refill cost in Thailand?
| Item on our online shop | Price | Volume | Cost of gas per litre |
|---|---|---|---|
| CO2 cylinder refill (exchange) | ฿390 | Up to 50 litres | ฿390 ÷ 50 = ฿7.80 |
| Additional CO2 cylinder (new, full) | ฿890 | Up to 50 litres | One-off purchase, then refilled at ฿390 |
| Soda Maker Kit | ฿3,990 (Inox and Glass ฿6,490) | Includes a cylinder to start | Not applicable |
At one litre of sparkling water a day, a cylinder lasts about seven weeks, and a year of sparkling water costs around seven to nine refills, or ฿2,730 to ฿3,510 in gas. The same year in half-litre bottles would be 730 bottles bought, carried and thrown away. We compare the two in detail in our article on plastic bottles and pollution.
How do you handle and store a CO2 cylinder safely?
A soda cylinder is safe when it is treated as what it is: a small pressure vessel. The habits below cover almost every situation.
- Keep it upright, indoors, out of direct sun and away from the stove or any heat source. Thai afternoon temperatures in a closed car or a sunlit balcony are exactly what the cylinder should avoid.
- Screw it into the machine by hand only. If it does not seat easily, stop and check the thread rather than forcing it.
- Never puncture, heat, drop or try to open a cylinder, and never attempt to refill it with an adapter.
- If you hear a hiss after fitting, remove the cylinder in a ventilated room and contact us. A cylinder that empties on its own should not be used again until checked.
- Store cylinders where children cannot reach them, and return empties for exchange rather than keeping them.
CO2 is not toxic at the quantities in a soda cylinder, but it is heavier than air, so a cylinder discharging in a very small closed space should be dealt with from a ventilated room.
Which water goes into the bottle?
The gas is only half of a good sparkling water; the other half is cold, clean still water. Most households in Thailand do not drink from the tap, for reasons set out in our guide to tap water in Thailand. The simplest source is a dispenser that makes drinking water on site: a Minairal Pure system on the kitchen line, or an Air system that produces mineral water from the humidity in the room. Both serve cold water, which carbonates far better than water at room temperature.
Frequently asked questions
How long does it take to refill a CO2 cylinder?
At one of our shops, a few minutes: the empty is swapped for a full one on the spot. By post, order the refill online, return the empty, and the full cylinder is delivered to you anywhere in Thailand. A second cylinder means there is no wait at all.
Where can I swap a cylinder in person?
At our four shops: Koh Samui (Bo Phut showroom), Phuket (Chalong), Hua Hin (Hin Lek Fai) and Koh Phangan (Thong Sala, inside DELITALY). Everywhere else, including Bangkok, order online with delivery across Thailand.
How many litres does one 380 g cylinder make?
Up to 50 litres of sparkling water. Strongly carbonated water uses more gas per bottle, so the real figure depends on your taste.
Is CO2 from a fire extinguisher or an aquarium shop safe for soda?
No. Those gases are not handled as food ingredients, and transferring them into a soda cylinder means overfilling and valve damage are likely. Use food-grade refills from a supplier.
Can I use a Minairal refill with another brand of soda maker?
Yes. Minairal cylinders are compatible with other major soda maker brands such as SodaStream, so you can bring the cylinder from your current machine for exchange.
