An Introduction Into Home Coffee Roasting

From Avacuppa Wiki

1 Coffee Roasting
2 Profile Roasting
3 Sample Roast Profile and Log
4 Related topics:

[edit] Coffee Roasting

Coffee roasting is simply the application of heat to the raw coffee beans. The only 3 criterias are:

the heat must be applied evenly - this would mean constant stirring and/or agitation of the beans.
apply the lowest heat possible - this is to avoid scorching and tipping of the beans.
the roasting process must be done in the shortest possible time - this is to avoid baking the beans.

Baking, as mentioned in criteria 3, produces undeveloped beans where the essential chemical (like caramelization of carbohydrates) and physical transformation (i.e., expansion) of the bean did not take place).

One first glance, criteria 2 and 3 above seems to be criteria contradicting each other. However, thinking about these 2 criteria together would suggests that there is a narrow range of temperature and time (thus, a window) that would be optimum in bringing out the best attributes of any given coffee bean. This temperature and time window would be affected by the following:

roaster being used due the efficiency and type of heat application(convective, conductive and/or radiant)
bean type due to the its density and moisture content (these attributes affects the thermal conductivity of the beans)

Determining the optimum temperature and time window for any given coffee bean could only be done by trial and error. Hence, it might be a good idea to find out if other roasters had a roast profile or any information (i.e., cupping notes) about the bean. When roasting, it is always useful to log information about your roast. A sample roasting log can be found here. Knowing exactly (or at least having a good idea) what a bean is doing at any point in time during the roast is key to have a coffee roasted just they way you like it.

The roaster you are using is of secondary importance only, the more important thing is to intimately know your roaster. In other words, a roaster using a cheap 'Heat Gun / Dog Bowl' (HG/DB) setup would most certainly produce an excellent roast compare to a roaster that simply push a button on an expensive roaster without taking into consideration the bean type and the roast profile that is it best for that bean. In summary, experience and knowing your bean and roaster are the keys to becoming a good roaster.

[edit] Profile Roasting

Profile roasting means you have a predetermined action plan when roasting. Thus, for any given time during the roasting process you would know when to do the following:

apply more/less heat
what type of heat to apply (conduction, convection and/or radiant heat)
apply more/less air (most roasters for home use do not have airflow control)

The information that could be included in the roast profile are:

Bean type (i.e., Ethiopian Sidamo)
Bean density (high, medium, low)
Moisture content
Weight before the roast
Weight after the roast (this information is required to know what the bean weight shrinkage is aka percent loss)
Date of the roast
Cupping notes of the roasted coffeee
Comments

When you do not have a roast profile for a certain bean type yet, it would be a good idea to search the internet for one (preferably, the roast profile did use the same roaster you have). The roaster manufacture usually provide some roast profile you can use (or information you can use to start a roast profile).

Once you have a roast profile and feel that you can still improve on it, then by all means make some subtle changes to it (this is the advantage of being a home roaster, you can tailor your roasts to suit your taste).

Your cupping notes will be guide you on whether you have arrived at the perfect roast profile for that bean or go on and continue the quest.

Note that for all greens beans we sell in Avacuppa, we have a roast profile you can use as a start. The roast profile, however, is specific to roasting using Gene Cafe.