CO2 vs Nitrogen Quiz
CO2 vs. Nitrogen vs. Mixed Gas Quiz
CO2, pure nitrogen, or a blended gas mix? The wrong choice leads to flat beer, over-carbonation, or ruined foam. Answer 5 quick questions and we'll identify the exact gas, equipment, and serving settings your system needs.
Why your gas choice matters
Pure CO2 works for most standard beers on direct draw systems. But as soon as you move to long draw (high pressure), pour nitro beers, or serve cold brew, the gas choice changes — and getting it wrong costs you kegs. A 25/75 CO2/N2 beer gas on a standard lager will flatten it in 3 days. Pure CO2 on a long draw at 30 PSI over-carbonates everything. This quiz walks through your beverage, system type, faucet, and pressure to give you the correct answer — then links to the right regulator and equipment.
Question 1 of 5
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What You Need
Serving Settings
Gas Comparison Quick Reference
| Gas | Blend | Use For | PSI Range | Regulator Fitting |
|---|---|---|---|---|
| Pure CO2 | 100% CO2 | Standard beer — direct draw or forced-air | 10–14 PSI | CGA-320 (right-hand thread) |
| CO2/N2 Blend (Brewers Blend) | 70% CO2 / 30% N2 | Regular beer — long draw glycol systems at 15–30 PSI | 15–30 PSI | CGA-580 (left-hand thread) |
| Beer Gas (G-mix) | 25% CO2 / 75% N2 | Nitro beers ONLY (stouts, nitro IPAs) | 25–35 PSI | CGA-580 (left-hand thread) |
| Pure Nitrogen | 100% N2 | Nitro cold brew, wine preservation, still beverages | 30–50 PSI | CGA-580 (left-hand thread) |
| CO2/N2 (cold brew) | 70% N2 / 30% CO2 | Sparkling cold brew coffee | 35–45 PSI | CGA-580 (left-hand thread) |
Critical: Beer Gas on Regular Beer. Using 25/75 CO2/N2 (beer gas / G-mix) on regularly carbonated beers flattens the keg within 3–5 days. The CO2 partial pressure in beer gas is only ~6–8 PSI equivalent — far below what is needed to maintain standard beer carbonation. Only use beer gas on nitro beers with a stout faucet. — BA Draught Beer Quality Manual, Appendix C
Regulator fittings are different by design. CO2 uses CGA-320 (right-hand thread). Nitrogen and all mixed gas cylinders use CGA-580 (left-hand thread). This prevents accidentally connecting a CO2 regulator to a high-pressure nitrogen tank.
Frequently Asked Questions About Draft Beer Gas
Should I use CO2 or nitrogen for my draft beer?
Use pure CO2 for standard beers on direct-draw and forced-air systems under 25 ft. Switch to a 70/30 CO2/N2 blend for long-draw glycol systems at 15–30 PSI. Use 25/75 beer gas only for nitro beers (stouts, nitro IPAs) with a stout faucet. Pure nitrogen is for still cold brew and beverage preservation, not carbonated beer.
What gas do I use for a nitro stout?
Nitro stouts and nitro IPAs run on beer gas — 25% CO2 / 75% N2 ("G-mix") — at 25–35 PSI through a stout faucet with an internal restrictor disc. The high nitrogen content and the restrictor plate together create the signature cascading pour. A stout faucet is required, not optional.
Can I use beer gas (75/25) on regular beer?
No. Running 25/75 CO2/N2 beer gas on regularly carbonated beer flattens the keg within 3–5 days. The CO2 partial pressure in beer gas is only about 6–8 PSI equivalent — far below what standard beer carbonation needs. Beer gas is for nitro beers only.
What's the difference between CGA-320 and CGA-580 fittings?
CGA-320 (right-hand thread) is the fitting for pure CO2 regulators. CGA-580 (left-hand thread) is used for nitrogen and all mixed-gas cylinders. The different threads are a safety design that prevents accidentally connecting a CO2 regulator to a high-pressure nitrogen tank. You need a regulator that matches your cylinder's fitting.
What gas blend do I need for a long draw system?
For regularly carbonated beer on a long-draw glycol system, use the Brewers Association standard 70% CO2 / 30% N2 blend at 15–30 PSI. At those pressures, pure CO2 slowly over-carbonates beer over time; the 70/30 blend holds the correct CO2 partial pressure while nitrogen supplies the extra push. It runs through a CGA-580 mixed-gas regulator.
What PSI should I run for nitro beer?
25–35 PSI on 25/75 beer gas through a stout faucet. Don't change the pressure to adjust foam — the restrictor plate in the stout faucet controls the cascade, so adjust the plate or faucet instead. Shop our gas regulators for the right CGA-580 mixed-gas setup.
Need a gas regulator or cylinder fitting?
We carry CO2 regulators (CGA-320), mixed gas / nitrogen regulators (CGA-580), secondary regulator panels, and all fittings for any gas setup. Same-day shipping from the Northeast.
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