Optimizing Harvest Timing for Enhanced Hop Quality in a Subtropical Climate Alvaro J. Bautista* and Shinsuke Agehara University of Florida, Institute of Food and Agricultural Sciences, Gulf Coast Research and Education Center, 14625 County Road 672, Wimauma, FL 33598, United States *Presenter: Alvaro J. Bautista Corresponding author: Shinsuke Agehara (sagehara@ufl.edu) Hops (Humulus lupulus L.) are a key ingredient in brewing, contributing bitterness, aroma, and microbiological stability. While traditionally cultivated in temperate climates, our previous research has demonstrated that subtropical regions like Florida offer unique opportunities for hop production, enabling two production cycles per year with supplemental lighting. Harvest timing is critical for optimizing hop cone biochemical composition, particularly alpha acids (AA), beta acids (BA), and essential oils, which directly influence beer quality. This study examined the seasonal and developmental dynamics of ‘Cascade’ hop cone chemistry to determine the optimal harvest window for both spring and fall growing seasons. Data were collected from 2021 to 2024 from the plants established in 2021 at the University of Florida’s Gulf Coast Research and Education Center in west-central Florida. Cone samples were collected at different days after flower induction (DAFI) to assess changes in AA and BA, cohumulone and colupulone, and essential oil composition. Acid levels showed significant seasonal variation. In spring, AA and BA ranged from 9.38% and 5.48% in 2021 to 4.48% and 2.0% in 2024, respectively. In fall, AA and BA ranged from 4.7% and 2.49% in 2021 to 2.97% and 2.0% in 2024, respectively. Acid accumulation also showed seasonal patterns, peaking at 36–48 DAFI in spring compared to 24–30 DAFI in fall. In contrast, cohumulone and colupulone maintained stable levels around 27.54% of total AA and 47.79% of total BA, respectively, throughout the study. Essential oil content increased during cone maturation, reaching its optimal aromatic profile at 36–42 DAFI (1.5 ml/100g). Myrcene (81.8% of total oil), the dominant terpene across all seasons, followed the same trend as total essential oil content. Humulene and caryophyllene peaked between 24 and 36 DAFI (19.7% and 10.9.% of total oil, respectively), while geraniol and linalool remained stable (0.5% and 0.7% of total oil, respectively) throughout maturation. These findings provide a foundation for optimizing hop production in non-traditional climates and highlight the importance of precise harvest timing to enhance hop quality for brewing applications. Future research will explore additional environmental, physiological, and management factors influencing hop maturation under subtropical conditions.
