Simple integrated condensate capture systems for effective VOC emission control in coffee roasting facilities

Coffee roasting emits substantial quantities of volatile organic compounds (VOCs), contributing to air pollution and creating occupational health risks for workers and nearby communities. Small-scale roasteries, which represent the majority of global operations, typically lack effective and affordable emission control technologies. In this study, we developed and field‑tested two low‑cost, integrated condensate capture systems, a conical hood captor and a cylindrical captor, designed for direct application to a 10‑kg gas‑fired batch roaster. Both systems were evaluated under real commercial conditions using Arabica (Coffea arabica) and Conilon (Coffea canephora) coffees. The conical hood achieved condensate recovery rates of 1.03–1.46 g/min·kg (109–144 g per 10‑kg batch), while the cylindrical captor recovered up to 150 g per batch. The collected liquids were acidic (pH 2–4) and rich in total organic carbon (up to 73.34 mg TOC/kg coffee), containing hazardous alpha‑diketones (diacetyl, 2,3‑pentanedione) and valuable aroma constituents such as caffeine, acetic acid, and furfural. Emission abatement ranged from 969 to 3767 mg VOC/Nm³, corresponding to reductions of up to 40 % relative to uncontrolled processes and 14–27 % below regulatory benchmarks. These results provide the first field‑scale demonstration that simple, scalable condensate‑capture systems can substantially mitigate VOC emissions and occupational exposures in small-scale coffee roasting. The approach offers a practical technological pathway for emission reduction in decentralized food industries, supporting environmental quality and worker health.