CO₂ Cylinders for Home Brewing and Keg Taps: What You Need to Know
If you’re setting up a home draft system or getting into home brewing, a reliable CO₂ setup is key to pouring perfect pints. Whether you're using a kegerator in the garage or running a keezer build in the basement, understanding how CO₂ cylinders work, what size you need, and how to refill them safely will save you time, money, and frustration.
In this guide, we cover the essentials for using CO₂ cylinders at home—based on what’s commonly available and permitted in Ottawa, Ontario.
Why CO₂ Is Essential for Draft Beer
CO₂ (carbon dioxide) serves two main purposes in a draft system:
Carbonation – CO₂ maintains the beer’s bubbles by keeping it under pressure.
Dispensing – It pushes beer from the keg through the tap line to your glass.
Without the right CO₂ pressure and tank size, you’ll deal with flat beer, foamy pours, or inconsistent flow—the last thing you want after a long brewing cycle or a party setup.
For a breakdown of CO₂ use in draft systems, this guide from Kegerator.com is a great starting point.
What Size CO₂ Cylinder Do You Need?
For home setups, the most common CO₂ cylinder sizes are:
2.5 lb – Very compact, fits inside small fridges (less common)
5 lb – Ideal for most kegerators (carbonates 5–10 kegs)
10 lb – Great for higher-volume use or multiple taps
20 lb – Overkill for small setups, but cost-effective long term
A 5 lb cylinder is usually the sweet spot for balancing space and refill cost. You can expect to carbonate and serve around 5 full-size (19L) Cornelius kegs before needing a refill.
Need help deciding? Homebrew Talk has helpful community insights on keg-to-cylinder ratios.
Can You Refill CO₂ Cylinders in Ottawa?
Yes—but not just anywhere.
CO₂ cylinders used for beverage dispensing must be:
Certified and in hydro test (every 5 years in Canada)
Fitted with the proper CGA-320 valve
Refilled at a licensed filling station using food-grade CO₂
At Rapid CO₂, based in Ottawa, we refill and service CO₂ tanks used for:
Home brewing setups
Garage kegerators
Event draft systems
DIY cold brew rigs
We offer on-site cylinder refills and hydro testing to ensure your tank is safe, compliant, and ready to pour. Want to learn more about hydro testing? See our CO₂ cylinder testing guide.
Is It Cheaper to Refill or Swap?
Refilling is usually:
Cheaper per pound
Better if you own a high-quality or aluminum tank
Less risky than receiving an expired or damaged swap tank
Some swap programs will exchange your tested, clean cylinder for one with only months of hydro life left. That’s why many brewers prefer refills—they keep their equipment and ensure full certification.
Final Tips for Home CO₂ Use
Store cylinders upright and at room temperature
Always turn off the regulator after use to prevent leaks
Get tanks visually inspected regularly, even between test intervals
Don’t over-tighten fittings—hand-tight is often enough
If you’re using your CO₂ cylinder inside a kegerator or keezer, make sure it’s secured and ventilated. CO₂ is heavier than air and can displace oxygen in enclosed spaces.
At Rapid CO₂, we help Ottawa’s home brewers and keg fans stay fully stocked and compliant. Whether you need a refill, a new tank, or hydro testing, we’re happy to help you pour clean, pressurized pints safely.
To book a refill or ask about setup advice, call 613-299-8412.
