Learn when to use 60/40 vs 70/30 CO2/nitrogen mix. Cellar gas setup explained.

If you’re running a pub, bar, or restaurant with draught beer, understanding beer gas is essential. The wrong gas mix affects your pour quality, causes excessive foam, and wastes product.

This guide explains beer gas mixes, when to use each type, and how to set up your cellar gas correctly.

What is Beer Gas?

Beer gas is a mixture of carbon dioxide (CO2) and nitrogen (N2) used to dispense draught beer and cider.

• CO2 maintains the carbonation in the beer—the fizz and sparkle
• Nitrogen provides the pushing pressure without adding extra carbonation

The ratio between these two gases affects how the beer pours and tastes.

Why Not Just Use Pure CO2?

Pure CO2 works for some applications, but it causes problems with many beers:

Over-Carbonation If the dispense pressure is too high (which it often needs to be for long runs or vertical lifts), pure CO2 dissolves into the beer. This makes it overly fizzy, changes the taste, and causes fobbing (excessive foam).

Nitrogen Solves This Nitrogen doesn’t dissolve into liquid as readily as CO2. By mixing nitrogen with CO2, you can push the beer at higher pressures without affecting the carbonation level.

Common Beer Gas Mixes

60/40 Mix (60% CO2, 40% Nitrogen)

Best for: Most lagers, standard ales, and ciders

This is the most common beer gas mix in the UK. It provides enough CO2 to maintain carbonation while the nitrogen enables higher pushing pressure without over-gassing.

Use 60/40 for:

• Standard lagers (Carling, Fosters, Stella, etc.)
• Mainstream ales on keg
• Most ciders
• General cellar gas applications

70/30 Mix (70% CO2, 30% Nitrogen)

Best for: Some premium lagers and higher-carbonation products

Slightly higher CO2 content for products that require more carbonation or shorter dispense runs.

Use 70/30 for:

• Some premium lagers
• Shorter dispense runs
• Products specified by the brewery as requiring 70/30

30/70 Mix (30% CO2, 70% Nitrogen) – Stout Gas

Best for: Stouts and nitrogenated beers

Higher nitrogen content creates the creamy, cascading pour characteristic of stouts like Guinness.

Use 30/70 for:

• Guinness and similar stouts
• Nitrogenated ales
• Some craft “nitro” beers

Pure CO2 (100%)

Best for: Post-mix soft drinks and some specific products

Used for soft drinks and occasionally for products with very short runs where over-carbonation isn’t a concern.

Use pure CO2 for:

• Post-mix soft drinks (Pepsi, Coca-Cola, etc.)
• Some speciality products as specified by the supplier

How to Choose the Right Mix

Check with Your Brewery or Supplier

The brewery or drink supplier will specify which gas mix their product requires. This is the definitive answer—always follow their guidance.

Consider Your Setup

Long Dispense Runs If your beer lines run a long distance from cellar to bar (or include vertical lifts), you’ll typically need a nitrogen-containing mix to allow higher pushing pressure.

Short Runs Very short dispense runs might work with pure CO2 or higher-CO2 mixes.

Multiple Products Most cellars use 60/40 as a standard because it works for the widest range of products.

Beer Gas Setup Guide

Equipment Needed

• Gas cylinder (appropriately sized for your usage)
• Primary regulator (connected to the cylinder)
• Secondary regulator(s) (to fine-tune pressure at each product)
• Gas lines (food-grade tubing)
• Connectors (to attach to kegs)

Typical Pressures

These are starting points—adjust based on your specific setup and product requirements:

Factors that affect pressure requirements:

• Length of beer line
• Vertical lift (cellar to bar height difference)
• Line diameter
• Temperature
• Product specifications

Troubleshooting Common Problems

Beer is too foamy/fobbing

• Pressure may be too high
• Beer may be too warm
• Lines may need cleaning
• Wrong gas mix for the product

Beer is flat

• Pressure may be too low
• CO2 may have run out
• Gas may not be connected properly
• Keg may be empty or faulty

Beer tastes off

• Lines need cleaning
• Beer is past its best
• Temperature issues
• Wrong gas type

How Much Gas Will You Need?

Gas consumption depends on volume dispensed and how efficiently your system runs.

Rough Guide for a 50L Cylinder:

These are estimates—actual consumption varies significantly based on sales volume and system efficiency.

Signs You’re Using Too Much Gas

• Frequently running out mid-week
• High foam/waste levels
• Hissing sounds (gas leaks)

If you’re going through gas faster than expected, check for leaks and ensure pressures aren’t set too high.

Beer Gas vs Cellar Gas – What’s the Difference?

These terms are often used interchangeably. Technically:

• Beer Gas typically refers to the mixed gas (CO2/N2)
• Cellar Gas is a general term for any gas used in cellar dispense

In practice, when someone says “cellar gas,” they usually mean beer gas (60/40 or similar mix).

Connecting and Changing Cylinders

Safety First

• Always store cylinders upright and secured
• Keep cylinders in well-ventilated areas
• Never store near heat sources
• Use the correct regulator for the gas type

Changing a Cylinder

1. Turn off the cylinder valve (clockwise)
2. Release pressure from the regulator
3. Disconnect the regulator from the empty cylinder
4. Connect the regulator to the new cylinder
5. Open the new cylinder valve slowly
6. Check for leaks (use leak detection spray or soapy water)
7. Adjust pressure if necessary

Ordering Beer Gas

When ordering beer gas, you’ll need to specify:

• Gas type (60/40, 70/30, 30/70, or pure CO2)
• Cylinder size (depends on your consumption)
• Quantity (how many cylinders)

For most pubs and bars, 60/40 mix in standard cylinders is the default order. If you dispense stouts, you’ll also need a separate 30/70 (stout gas) cylinder.

FAQ

Can I use one gas type for everything? Not ideally. Stouts require a different mix (high nitrogen) than lagers. However, 60/40 works for most non-stout products.

What happens if I use the wrong gas? Using too high a CO2 concentration causes over-carbonation (fizzy, foamy pours). Using too low causes flat beer. Using the wrong mix on stout won’t give you the proper creamy cascade.

How do I know when the cylinder is running low? Most regulators show cylinder pressure. When it starts dropping significantly, you’re running low. Ordering before it empties avoids running out mid-service.

Can I mix different gas types? No. Use pre-mixed gas from your supplier. Attempting to mix gases yourself is dangerous and won’t produce consistent results.

Is beer gas the same as CO2? No. Beer gas is a CO2/nitrogen mix. Pure CO2 is different and used for specific applications (mainly soft drinks).

Summary

• 60/40 (CO2/N2) is the standard for most lagers, ales, and ciders
• 70/30 is used for some premium lagers and specific products
• 30/70 (stout gas) is required for Guinness and similar stouts
• Pure CO2 is mainly for post-mix soft drinks
• Always follow brewery/supplier recommendations for gas type
• Proper pressure settings prevent foam issues and maintain quality

Related Articles:

• CO2 for Beverage Dispensing: Complete Setup Guide
• How Much Does Industrial Gas Cost in the UK?
• Gas Cylinder Safety: Storage, Handling & Best Practices