Coffee Roasting Machines- Coffee Roasters Australia

The way in which coffee is roasted can have a profound effect to its taste. Roast too quickly at too high a temperature, and you'll scorch the exterior of the bean. Roast too slowly at too low a temperature and you'll sap the bean of its flavour. Over the years, numerous roasting methods have been developed to address these challengers, all with the same objective: To transfer heat to the coffee bean, initiating a series of chemical reactions that prepare it for consumption. Most roasting methods include the following six phases:

1. Drying Cycle:
This is the first phase of the roasting process, when the temperature of the beans rises to 100 degrees centigrade. Also in this phase, the beans change from a bright green colour to a pale yellow.

2. First Crack:
When the beans reach 160 degrees centrigrade, complex chemical reactions begin to occur causing a cracking sound.

3. Roast initiation:
The beans swell to 140 - 160% of their initial size. Elements within the beans begin to caremalise, giving the beans their brown colour.

4. Pause:
In this phase, the audible cracking ceases, but the reactions continue. The time of this silence will depend on the amount of heat applied by the roaster.

5. Second Crack:
The progressive dehydration of the beans has made them brittle. As a result, more cracking can be heard. It is at this stage that elements in the bean begin to carbonise, producing the burnt characteristics of extremely dark roasts.

6. Stopping the Roast
Once the optimal amount of roasting time has elapsed, the beans must be cooled quickly. This is usually accomplished by introducing large amounts of cool air.

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