Roasting converts the nicely fermented beans to a awesome smelling and tasting nibs. Roasting has three purposes, flavor development, sterilization and loosening up the nibs prior to winnowing. There are several style of doing it but all of them follow the same general rule, keep the beans rolling at temperature of 90 to 135 degrees Centigrade for one to two hours. These values varies in accordance with the variety, origin and desired flavor outcome. There are tricks that uses high starting temperature then lowering it toward the end.
Oven roasting. It can be accomplished by placing the bean on perforated trays by single layer. Increasing it will reduced its efficacy. Another problem with this method is the distribution of heat inside the compartment. Tray rearrangement maybe necessary to compensate for this. Ovens are much much cheaper and easier to source than good drum roaster. The only thing that is holding me back from acquiring one is its size. I don’t have space for it.
Drum roasting. The queen or roasting. Everywhere I look, they are talking about the horizontal drum roaster. The concept is so simple. The beans are continuously tumbled inside a rotating and heated drum until the set outcome is attained. There are many variants. From DIY manual rotate, drill powered up to very sophisticated that can be afford only by large capitalist. Oh! Sorry, the expensive that I ma referring to are coffee roasters. Brands that have RPM control can be used successfully for cacao.
Pan roasting. It is the oldest method of roasting. Placing the beans on pan. Firing up the heat source. Then continually mixing the beans until the desired result is achieved. What are the cons of this roasting style? Well, ask me? When I said “mix it continually”, it means mix it for few seconds, stop for a while, then mix again. The beans that are temporarily stuck in bottom are likely to get burnt which is not desirable. The longer the stop the more scorched beans . We want it roasted, not burnt.
There is no option for temperature control. Memorizing the flame glow is always the first bet. Better if a metal built thermometer is available, intermittent checking can be done. Other parameters such as roasting duration and bean flavor could be set and assessed. I am still doing the pain in the ass pan roasting. Doing my very best to overcome the cons. I cannot delegate the task to others due to its complexity. The risk involved is too great, loosing valuable customers. The plan for acquiring a drum roaster is already on the line. We recently talked to a supplier but got screwed up.