Mixed Gas Fundamentals

Mixed Gas Fundamentals

Gas (CO2 and sometimes N2) is a normal ingredient in beer. Gas is also the method we use to push beer from the keg to the glass. The right balance of mixed gases will keep the dissolved gas levels perfect. The wrong balance will damage the beer by changing dissolved gas levels in the beer. Any change in gas levels will affect the flavor and appearance of the beer. The primary concern is gas content change, with the key elements: pressure and temperature.

Pressure is the force of gas molecules hitting the walls (and floor and ceiling) of a container. The amount of force (pressure) depends on the number of molecules hitting the surfaces and the speed at which they hit. For example, imagine an empty beer keg with 15 psig of CO2 sitting in a cooler, not connected (without at coupler.)

Our keg contains an unchanging number of CO2 molecules. If you take it into the sun and let it warm up, those molecules will move faster, hitting the walls harder, exerting more pressure. If you put the keg into the freezer, the molecules will slow down, hitting the walls with less speed, dropping the pressure.

Blender Technology

McDantim, Inc. has specialized in on-site gas blenders since 1988 with over 200,000 Trumix® systems around the world. Blenders are a unique design approach to blending on-site and offer value to the entire gas management system.

By selling the McDantim Trumix® blender, you have committed to providing the most consistent, most cost effective, and most reliable tool available for providing mixed gas. The more you learn about using and choosing the right blend and the right gas source, the better service you provide for your customers. In all cases, the real reason for using mixed gas is to help the retailer deliver the same beer the brewer brewed. We do this by making sure that the gas content of the beer remains constant until the keg goes empty, no matter how long that is.

Why Mixed Gas?

Potential Customers need Mixed Gas for two reasons:

1. They are serving a nitrogenated beers.

2. They dispense some or all of their beers over the "balance point". (The pressure above which 100% CO2 will over-carbonate the beer.)

All beers have CO2 dissolved into them. Nitrogenated beer has N2 dissolved into it also. To properly serve nitrogenated (nitro) beers mixed gas must be used.

1. Pure CO2 will allow the N2 to come out of solution.

2. Pure N2 will allow the CO2 to come out of solution.

In either case the beer no longer looks or tastes the same . The correct blend with these beers is usually dictated by the brewer but in most cases it will be 25 to 30% CO2 and the rest Nitrogen. Guinness, for example, recommends 25% CO2 with the beer dispensed at 30 psi. Maintaining the correct blend and dispensing pressure are necessary to maintain the correct proportion of both gases. Note: With most nitrogenated products a restricting/agitating faucet (often referred to as a Guinness or stout faucet) will greatly enhance the appearance of the nitrogenated effects.

Beers served above the balance point are a different story altogether. All beers, whether Budweiser or Black Butte Porter have a certain amount (vol./vols) of CO2 dissolved in the beer. The carbonation is an ingredient chosen carefully by the brewer. Our job is to pick a blend that maintains this level of dissolved CO2. We use the temperature and dispense pressure of the system conditions and chose a blend of CO2 to match. Nitrogen simply provides the extra pressure necessary to dispense the beer.

The correct blend keeps the beer at the correct carbonation level throughout the whole keg, no matter how long it is on tap.

Mixed Gas will (used correctly in a properly designed system):

• Keep a "nitro" beer properly carbonated and nitrogenated

• Keep beers properly carbonated, no matter how long they're on tap

• Prevent beers from going flat

• Prevent beers from going wild

• Prevent wasted beer

• Reduce foaming problems due to temperature fluctuations.

Mixed Gas will not:

• Give your beer the creamy head of a "Guinness"

• Fix Beer that is already over-carbonated

• Eliminate all foaming in poorly designed or maintained dispense systems

Too much CO2 in the blend will:

• Cause foaming and over-carbonating. (It's just a matter of time.)

Too little CO2 in the blend will:

• Cause the beer to go flat. (Guaranteed, it's just a matter of time.)