How to Roast Coffee

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Tuning Your Roaster

HTR 1.04 Gas Supply

Before you buy a roasting machine, you must ensure that your roastery’s gas supply is sufficient to power the burner. An inadequate gas supply limits your batch capacity and causes your roasts to take too long to complete — which is not ideal for either flavour or productivity.

 

Appropriate Gas Pressure

Most countries in the world measure the pressure in their gas mains in kilopascals (kPa); other units of pressure commonly used for gas supplies include millibars (mbar), pounds per square inch (psi), and inches of water column (inches wc).

To help you handle this situation, the following calculator allows you to quickly convert from one unit of pressure to another.

The gas pressure available varies by geographical area In Australia, for example, commercial properties usually provide gas mains pressure between 1.1–2.75 kPa. In the UK and many European countries, the gas pressure in the mains network is typically 7.5 kPa, while the pressure in the internal pipework is reduced to 2.1 kPa by a regulator at the gas meter.

The optimal gas pressure is generally at the top of the manufacturer’s recommended range. In other words, if the manufacturer recommends 2.5–3 kPa, try to bring 3 kPa to your machine. If you’re not sure of the pressure that your machine requires, look for a description of the specifications that is usually posted on the serial plate, which may be mounted on the side or back of the machine. If in doubt, consult with the manufacturer about the specifications of your machine.

You can adjust the pressure of the gas reaching the roaster by fitting an appropriate regulator. If the pressure available from the mains is lower than what is needed at the roaster, it may be possible to install a gas booster to increase the pressure.

 

Gas Flow

A roaster doesn’t just need a specific pressure to operate correctly — it also needs a sufficient amount of gas available. If the gas pipe feeding the roaster is too narrow,