WHY DO SOME COFFEE BEANS HAVE LOWER CAFFEINE?

Varietal Differences: Coffee beans come from different species of the Coffea plant, with the two most commercially significant being Coffea arabica and Coffea canephora (commonly known as Robusta). Arabica beans, prized for their nuanced flavours and smoothness, generally contain less caffeine than Robusta beans. Robusta, on the other hand, is known for its higher caffeine content and stronger, more bitter flavour profile.

Growing Conditions: The environment in which coffee plants are cultivated plays a crucial role in determining caffeine levels. Factors such as altitude, soil composition, climate, and rainfall can all influence caffeine synthesis within the beans. Generally, coffee plants grown at higher altitudes tend to produce beans with lower caffeine content. This is believed to be an adaptive response to the stress of growing in harsher conditions, where caffeine acts as a natural insect repellent and protective mechanism for the plant.

Processing Methods: The method used to process coffee beans after harvesting can also impact their caffeine content. There are two primary processing methods: the dry/natural process and the wet/washed process. In the dry process, beans are dried with their fruit pulp intact, which can result in a slower breakdown of caffeine. Conversely, the wet process involves removing the fruit pulp before drying, which may lead to some loss of caffeine during fermentation and washing.

Roasting Profiles: Roasting is where green coffee beans are transformed into the aromatic brown beans we recognise. Interestingly, caffeine is relatively stable during the roasting process, meaning that the duration and temperature of roasting don't significantly alter caffeine content. However, darker roasts tend to have a slightly lower caffeine content by volume compared to lighter roasts, as the longer roasting time can lead to some caffeine degradation.

Blending and Mixing: Coffee blends, which combine beans from different origins and varieties, offer roasters an opportunity to create unique flavour profiles while also potentially moderating caffeine levels. By blending beans with varying caffeine content, roasters can tailor their blends to achieve desired taste characteristics and caffeine potency.