Kegnotes

Topic

CO2 Systems

Tank sizes, pressures, refilling, and gas troubleshooting.

CO2 is the part of a kegerator that everyone hopes they don't have to think about, and the part that you absolutely have to think about if you want consistent pours. The tank size, the pressure, the refill cadence, the regulator setup — none of it is rocket science, but small mistakes here cause most of the foamy/flat/short-pour problems home kegerator owners deal with.

The decisions you make once: tank size (5lb vs 10lb vs 20lb), regulator type (single-gauge vs dual-gauge), and primary vs secondary regulators if you're running multiple beer styles. The decisions you make ongoing: serving pressure per beer style, refill timing, leak checks.

For the math on how long your specific tank lasts: try the CO2 tank lifespan calculator. Plug in tank size + serving pressure + kegs per month; out comes months-to-refill, refills per year, and annual cost. Plus a side-by-side of 5lb / 10lb / 20lb tanks for your specific usage.

Below: everything we've written on CO2, from "5 vs 10 vs 20 lb tank for a 2-tap kegerator" to leak diagnostics to the math on how long a tank actually lasts.

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Frequently asked: co2 systems

What size CO2 tank do I need for a home kegerator?

For a 1-tap kegerator with moderate use, 5lb tank is fine — gives roughly 6-8 kegs worth of CO2. For a 2-tap or heavy use, 10lb is the sweet spot — refill every 6-12 months. 20lb makes sense if you have outbuildings, host frequently, or want to refill once every couple of years. Larger tanks have a slightly better cost-per-pound at refill time.

Where can I refill a CO2 tank?

Welding supply stores (the cheapest option, $20-35 for a 5lb refill). Homebrew shops ($25-40 per refill). Some sporting goods shops that handle paintball/airsoft refills will do food-grade CO2 if asked. Avoid generic "gas refill" places that don't specify food-grade — the dye additives in industrial CO2 are not OK for beer.

What's the difference between single-gauge and dual-gauge regulators?

Single-gauge shows only the serving pressure (10-12 PSI). Dual-gauge also shows tank pressure (800-1000 PSI when full, dropping toward 0 as it empties). For home use, dual is worth the extra $20 because it tells you when to refill before you run out mid-party. Single-gauge means you guess.

Why does my CO2 tank empty faster than expected?

Most likely a slow leak. A pressurised system loses gas at every imperfect seal — regulator-tank junction, gas-line clamps, coupler quick-disconnect, keg o-ring. Soap-test every joint while the system is pressurised; tighten or replace as needed. The second most common cause is leaving the regulator at higher pressure than you need (cranks the gas through the system faster).

Can I use the same CO2 tank for two different beers?

Yes if both beers want similar serving pressure (most lagers and ales at 10-12 PSI). No if one wants very different pressure (a nitro stout at 30 PSI vs a lager at 10 PSI). For mixed setups, you need either two regulators or a secondary regulator off your primary tank.

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