Beer Gas Blend Calculator

Beer Gas Blend Calculator | CO2/N2 Mix Guide | Wholesale Beer Parts

Beer Gas Blend Calculator

Choose the wrong gas blend and you'll pour flat beer, waste CO2, or ruin a keg. Our calculator matches your beer style and system type to the right CO2/N2 ratio, serving pressure, and regulator — all based on the Brewers Association Draught Beer Quality Manual, 4th Edition.

Why gas blend matters for draft beer

The gas you push beer with directly controls carbonation, mouthfeel, and pour quality. Pure CO2 is correct for most regularly carbonated beers served on direct draw systems. Beer gas (25% CO2 / 75% N2) is required for nitro pours. Brewers blend (70% CO2 / 30% N2) prevents over-carbonation in long draw systems operating at high pressure. The wrong choice — putting beer gas on a standard lager, or running pure CO2 on a long draw at 30 PSI — costs you kegs and customer satisfaction.

How the gas blend calculator works

Select your beer style (or beverage type) and system configuration. The calculator determines the correct gas blend based on:

  • Desired carbonation level — determined by beer style. Ales and lagers need 2.4–2.6 volumes of CO2; nitro stouts use only 1.1–1.3 volumes; hard seltzer runs 3.0+ volumes.
  • System type and length — Direct draw (under 25 ft) runs at 10–14 PSI with pure CO2. Long draw glycol systems often require 20–30+ PSI, which forces the use of blended gas to prevent over-carbonation.
  • CO2 partial pressure — The key principle: only the CO2 percentage in the blend determines carbonation. Nitrogen is inert and adds push force without carbonating. At 14 PSI of pure CO2, the partial pressure is 14 PSI. At 30 PSI of 70/30 blend, the CO2 partial pressure is 21 PSI (approx) — in range for standard beers.

Select your options below and click Get Gas Recommendation to see the blend, PSI range, and regulator type for your exact setup.

When to use blended gas vs. pure CO2

  • 100% CO2 — All direct draw and forced-air systems under 25 ft for standard beers, cider, wine, and seltzer.
  • 70% CO2 / 30% N2 — Long draw glycol systems for regularly carbonated beers. The nitrogen provides inert pushing force at high PSI while the CO2 percentage keeps carbonation stable.
  • 25% CO2 / 75% N2 — Nitro beers only. Requires a stout faucet with restrictor plate. Never use on standard beer.
  • 100% N2 — Still nitro cold brew coffee. Nitrogen adds no carbonation, preserving the smooth, creamy texture without bubbles.

Blend your own gas on site with a gas blender

Once you know you need a blend like 70/30 or 25/75, you have two ways to get it: buy pre-mixed cylinders from your gas supplier, or blend it yourself on site with a gas blender. A blender connects to a bulk CO2 tank and a bulk nitrogen tank and mixes them to an exact ratio on demand. Because bulk CO2 and bulk nitrogen are far cheaper per cubic foot than pre-mixed cylinders, a blender usually pays for itself within a year on any bar running more than a few long-draw taps.

We carry the McDantim Trumix line of gas blenders — the industry standard, field-adjustable and accurate to ±2%:

  • Single Blender Trumix — one fixed blend output (e.g. 70/30). Ideal for a bar serving one gas blend across all taps.
  • Double Blender Trumix — two simultaneous blends from one unit (e.g. 70/30 for standard beer plus 25/75 beer gas for nitro).
  • Triple Blender Trumix — three simultaneous blends for large or mixed tap lists.
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Your System

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Gas Blend
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Serving PSI Range
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Regulator Type
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CO2 / N2 Ratio
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Gas Blend Reference Guide

Application Gas Blend PSI Range Regulator Notes
Standard beer — direct draw (under 25 ft) 100% CO2 10–14 PSI CO2 dual-gauge (CGA-320) Most beers at 36–38°F
Standard beer — long draw (25–100+ ft) 70% CO2 / 30% N2 14–30 PSI Mixed gas dual-gauge (CGA-580) Prevents over-carbonation at high pressure. BA recommended default for long draw.
Nitro stout / Nitro IPA 25% CO2 / 75% N2 (Beer Gas) 25–35 PSI Nitrogen / mixed gas (CGA-580) Requires stout faucet with restrictor plate. NOT for regular beer.
Cold brew coffee (carbonated) 100% CO2 35–45 PSI CO2 dual-gauge (CGA-320) High PSI for cold brew on CO2
Cold brew coffee (still / nitro) Pure N2 or 70% N2/30% CO2 30–45 PSI Nitrogen regulator (CGA-580) Nitrogen is inert — adds no carbonation
Hard cider 100% CO2 8–12 PSI CO2 dual-gauge (CGA-320) Lower PSI than beer; cider is sensitive to over-carbonation
Sparkling wine / Prosecco 100% CO2 8–10 PSI CO2 dual-gauge (CGA-320) Use wine-specific fittings and couplers
Hard seltzer 100% CO2 14–16 PSI CO2 dual-gauge (CGA-320) Higher carbonation than beer
⚠ WARNING: Never use 25/75 CO2/N2 (beer gas / G-mix) on standard regularly carbonated beer. It will flatten the beer within 3–5 days because CO2 partial pressure is too low to maintain carbonation. — BA Draught Beer Quality Manual, 4th Ed.
Regulator Fitting Guide: CO2 tanks use CGA-320 fittings (right-hand thread). Nitrogen and mixed gas tanks use CGA-580 fittings (left-hand thread, to prevent accidental CO2 connection). Never attempt to connect a CO2 regulator to a nitrogen or mixed gas tank.

Frequently Asked Questions About Draft Gas Blends

Can I use beer gas (25/75 CO2/N2) on regular beer?
No. Beer gas (also called G-mix) has too low a CO2 partial pressure to maintain normal carbonation in standard ales and lagers. Beer served on 25/75 CO2/N2 will go flat within 3–5 days. Use beer gas exclusively for nitro stout, nitro IPA, and other nitro-style beers that require a restrictor-plate stout faucet.
What's the difference between a CO2 regulator and a nitrogen regulator?
CO2 regulators use a CGA-320 fitting with a right-hand thread. Nitrogen and mixed gas regulators use a CGA-580 fitting with a left-hand thread — this prevents accidentally connecting a CO2 regulator to a nitrogen tank. Never attempt to force a CO2 regulator onto a nitrogen cylinder; the threads are designed to be incompatible.
Why do long draw systems need blended gas instead of pure CO2?
Long draw systems often need 20–30+ PSI to push beer through long runs of barrier tubing. At those pressures, pure CO2 will slowly over-carbonate most beers, causing persistent foaming after 3–7 days. A 70/30 CO2/N2 blend provides enough CO2 partial pressure to maintain correct carbonation while the nitrogen supplies the extra push force inertly. This is the Brewers Association standard recommendation for long draw systems.
Do I need a special faucet for nitro beer?
Yes. Nitro beer requires a stout faucet with an internal restrictor plate. The plate creates the turbulence that activates the nitrogen gas, producing the signature creamy cascade. Pouring beer gas through a standard faucet will result in uncontrollable foam. For mixed tap lists, a flow-control faucet can handle nitro at very low flow settings, but a dedicated stout faucet is still the best solution for Guinness and nitro IPAs.
Can I use pure nitrogen to dispense regular beer?
No. Nitrogen is inert and does not dissolve in beer. Using pure N2 to push beer will rapidly strip all carbonation, producing a completely flat, lifeless pour. Always maintain at least some CO2 in the blend for any beer that's supposed to be carbonated. Only pure nitrogen (or very high N2 blends) is appropriate for still cold brew coffee and other non-carbonated beverages.
How do I know what serving pressure to use for my beer?
Serving pressure depends on your beer style's target carbonation level and the beer temperature. For most ales and lagers at 36–38°F, 10–14 PSI of pure CO2 is correct. Use our calculator above — select your style and system type, adjust the pressure, and the recommended blend and PSI range will account for both carbonation requirements and system resistance.
Should I buy pre-mixed gas or use a gas blender?
If you run more than a few long-draw taps, a gas blender almost always wins. Pre-mixed cylinders are convenient for one or two taps, but you pay a premium per cubic foot. A gas blender (such as the McDantim Trumix) mixes bulk CO2 and bulk nitrogen to an exact ratio on demand, so you only buy cheap bulk gas. For most multi-tap bars it pays for itself within a year, and a double or triple unit can supply several different blends at once.

Need a CO2, nitrogen, or mixed gas regulator?

We carry the full range of draft gas equipment — CO2 dual-gauge regulators, nitrogen regulators, secondary regulator panels, and all CGA-320 and CGA-580 fittings. In stock and ready to ship from the Northeast for bars, breweries, and installers.

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Wholesale pricing available for volume orders. Call 800-821-0114 for bulk regulator packages.

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