Effects of Coffee Bean Thermal Treatments on Particle Size Distribution and Espresso Bioactive Compounds

(1) Background: Variations in bean temperature before grinding are a little-studied factor, but they can potentially influence the characteristics of the resulting powder and the chemical and physical properties of the espresso beverage. This study investigated the effect of two heat treatments, heating and cooling, applied to coffee beans immediately before grinding. (2) Methods: The analyses focused on powder particle size distribution (laser diffraction), impact on the operation of the coffee grinder (noise and electrical absorption), chemical-physical properties of the beverage, caffeine and chlorogenic acid content (HPLC-DAD) and profile of volatile organic compounds (HS-SPME-GC-MS). (3) Results: Heating induced a decrease in the content of caffeine and chlorogenic acids and a change in the aromatic profile consistent with phenomena like accelerated aging (increase in hexanal). Cooling treatment had similar, but less pronounced, effects, although it reduced caffeine extraction and some aromatic compounds. (4) Conclusions: The study demonstrated that the temperature of the coffee beans prior to grinding is a key factor to consider in terms of the particle size distribution of the resulting coffee grounds, as well as the content of bioactive compounds and volatile organic compounds, which can significantly influence various aspects of the final espresso’s quality