Homebrew CO2: Refills, Exchanges, and Kegging.
CO2 is the quiet workhorse behind clean pours, stable carbonation. This page helps you pick the right tank size, avoid the most common setup mistakes, and find places that do refills or exchanges near you.
Quick start (the “I just want beer” version)
If you’re building a basic kegerator
- Tank: 5 lb is fine for light use, 10 lb is comfy, 20 lb is the “stop thinking about it” size.
- Regulator: dual-gauge (tank pressure + output). Buy once, cry once.
- Gas line: 5/16″ ID is common. Keep it clean, don’t kink it.
- Disconnects: ball-lock is most common; pin-lock exists and loves to confuse people.
- Leak test: do this before you celebrate. Most “my tank emptied overnight” stories are leaks.
If you already have a SodaStream tank or adapter setup
You can absolutely power a carbonation rig with a larger tank, but keep the safety and compatibility straight: verify your adapter is rated for CO2, keep the tank upright, and don’t run mystery fittings from a sketchy listing. If you’re not sure what you have, a local supplier can tell you in 30 seconds if you ask the right question (see call script below).
Recommended starter setups
Three sane paths. Pick one and go. Most beginners should start with exchange (it’s faster and less hassle).
Budget / Small footprint (5 lb + exchange)
- Best for 1–2 kegs and limited space.
- Cheapest to get going, easiest to carry.
- Swap when empty and keep brewing.
Balanced (10 lb + exchange or refill)
- Great “default” size for most homebrewers.
- Fewer trips than 5 lb without being massive.
- Either swap (exchange) or refill customer-owned (if offered).
Set-and-forget (20 lb + exchange)
- Best convenience per trip. Lasts a long time.
- Heavier and taller, but the least annoying long-term.
- Perfect if you run multiple kegs or brew often.
Gear checklist (what matters and what’s optional)
Must-have
- CO2 tank (5/10/20 lb are most common)
- Dual-gauge regulator (or a quality single-stage regulator)
- Gas line + clamps (use real clamps, not “hope”)
- Proper keg disconnects (ball-lock / pin-lock)
- Spare O-rings (cheap insurance)
- Leak check method (starsan spray or soapy water)
Nice to have
- Manifold to feed multiple kegs
- Secondary regulator (different pressures per line)
- Inline shutoff + check valves
- Wrench for fittings (don’t round your nuts, hero)
- Wall/floor strap (keeps cylinders from falling)
Avoid / common traps
- Cheap “mystery” regulators that creep pressure
- Over-tightening fittings (crushes seals, causes leaks)
- Ignoring O-rings on disconnects
- Storing tanks on their side (don’t do that)
- Assuming every supplier will refill your cylinder
Setup & dial-in (so it pours right and stays carbonated)
Step-by-step dial-in (simple + reliable)
- Mount the tank upright (stable surface, strap if possible).
- Attach regulator snug, not gorilla-tight. Use the right washer/seal if your regulator requires it.
- Pressurize slowly and watch for obvious leaks.
- Set output pressure for your typical serving range (most setups live in the 10–14 PSI neighborhood, but your system, line length, and temperature matter).
- Leak check everything: tank valve, regulator connection, regulator body, hose clamps, disconnects, keg posts.
- Give it time: carbonation is not a microwave. Stable results come from steady pressure at stable temperature.
How to spot a leak fast
- Tank empties “overnight” or in a couple days with minimal pouring.
- Regulator output drifts or won’t hold steady.
- Hissing near the regulator, posts, or disconnects.
- Bubbles when sprayed with starsan/soapy water.
If you find a leak, fix it, then do the full check again. Leaks travel in packs.
Troubleshooting (symptom → likely cause → fix)
| Symptom | Likely cause | Fix |
|---|---|---|
| Tank empties fast | Leak at a fitting, disconnect, or keg post | Leak test everything; replace O-rings; re-seat disconnects; tighten clamps |
| Beer is foamy | Temp too warm, pressure mismatch, line balance off | Chill fully; stabilize pressure; check line length and serving pressure |
| Beer is flat | Not enough time at pressure; leak; pressure too low | Fix leaks; set stable pressure; wait; don’t keep “bursting” randomly |
| Regulator pressure “creeps” upward | Regulator seat failure / low-quality regulator | Rebuild/replace regulator; avoid mystery regulators |
| No gas flow | Tank valve closed, check valve stuck, line kinked | Open valve; inspect manifold/check valves; straighten/replace gas line |
| Disconnect won’t seal | Worn O-ring, wrong disconnect type, damaged post | Replace O-ring; confirm ball-lock vs pin-lock; inspect posts |
| Frozen regulator / icing | Very fast gas release or liquid CO2 entering regulator | Slow usage; keep tank upright; don’t run the tank on its side |
| Weird metallic taste (rare) | Line contamination or dirty hardware | Clean lines; replace old tubing; sanitize gear properly |
Refill vs exchange for homebrew (what’s best?)
Exchange (swap) is best if you want “easy”
You hand them your empty, they hand you a full one. Fast. Fewer rules. Often available at places that already manage cylinder inventory. If you’re running a kegerator and don’t care about “this exact tank,” exchange is usually king.
- Usually faster and more available
- Good for standard 5/10/20 lb tanks
- Great if you don’t want to worry about certification dates
Refill is best if you care about cost (and your tank)
Refill means they fill your specific cylinder. This can be cheaper long-term, but it depends on your area, your tank type, and whether the shop will fill customer-owned cylinders.
- Potentially cheaper per pound
- You keep your own cylinder
- Some places require a current cert/hydro date
“Food grade” CO2 question
People ask this a lot. In practice, reputable suppliers serving beverage/homebrew are a safe bet. If you want to be extra sure, ask the supplier if their CO2 is intended for beverage use. Don’t overthink it, but also don’t buy gas from a place that can’t answer basic questions.
Call script (ask it like this to get a real answer)
Most wasted trips happen because people ask the wrong question. “Do you refill CO2?” is too vague. Try this instead:
- If they say “exchange only,” you’re done. That works fine for homebrew.
- If they say “we refill,” ask if walk-ins are allowed and what hours.
- If they sound confused, ask if they handle “beverage CO2” or “homebrew CO2.”
Safety notes (short, serious, and actually relevant)
- Keep cylinders upright and stable. Falling tanks can wreck valves and ruin your day.
- Ventilation matters. CO2 can displace oxygen in small sealed spaces (especially basements/closets).
- Don’t store in extreme heat. Keep away from direct sun and high temps.
- Use the correct fittings. Forcing incompatible threads is how leaks and failures happen.
- Move tanks carefully. Cap/cover the valve if you have it, and don’t toss it in your trunk like a bowling ball.
Homebrew CO2 FAQ
The goal here is fewer wasted trips, fewer leaks, and fewer “why is my beer foam?” moments.
Should I start with exchange or refill?
What tank size should I buy for a kegerator?
- 5 lb: works, but you’ll swap/refill more often.
- 10 lb: the “default good choice” for most people.
- 20 lb: the “stop thinking about it” size if you have room.
Why do some places say “we don’t refill customer-owned tanks”?
Do I need “food grade” CO2 for homebrew?
My tank emptied overnight. What’s the most common cause?
Why is my beer foamy even when carbonation seems fine?
- Beer isn’t cold enough (temperature swings cause chaos).
- Serving pressure and line length aren’t balanced.
- Pressure is too high for your setup.
- Dirty lines/taps can contribute.
What PSI should I set for serving?
Why does my regulator freeze or ice up?
Can I transport a CO2 cylinder in my car safely?
What’s the fastest way to find homebrew CO2 suppliers on this site?
Find CO2 near you (homebrew-friendly)
Use these links to open the directory already filtered for homebrew. If you’re new: start with exchange. If you’re optimizing cost: check refill options.