What are the two primary factors in roasting that contribute to bitterness?

The two primary factors in roasting that contribute to bitterness are indeed the products of Maillard reactions and caramelization. During the roasting process, the Maillard reaction occurs between reducing sugars and amino acids, creating complex flavor compounds. While this reaction is crucial for developing a wide range of desirable flavors and aromas in coffee, it can also produce bitter compounds, especially if the desired roasting time or temperature is exceeded.

Caramelization involves the thermal degradation of sugars, which can also lead to bitterness when sugars are heated beyond a certain point. This process creates new flavors and colors but can introduce bitterness if not carefully managed. Both Maillard reactions and caramelization are critical in determining the final flavor profile of roasted coffee, making them key contributors to perceived bitterness.

In contrast, dehydration and fermentation would not be the primary drivers of bitterness in the context of roasting, as they relate more to the processing of green coffee beans rather than direct effects during roasting. High temperatures and humidity can influence the roasting environment but do not accurately pinpoint the biochemical reactions that lead to bitterness. Lastly, chlorogenic acids are present in green coffee beans and may contribute to bitterness, but they are influenced during roasting through the reactions mentioned rather than being standalone factors in bitterness production during the roasting process.