September 2025 The Independent Voice

The benefits were clear, especially in an industry that advocates for producers’ economic and social empowerment. Yet, some coffee professionals are still hesitant to accept them….”

Potassium: A Silent Partner in Kona Coffee Quality

The Role of Potassium in Coffee Flowering, Cherry Set, and Cup Quality
Potassium (K) is thought of as the “quality nutrient” in coffee production. Unlike nitrogen, which drives vegetative growth, potassium plays a pivotal role in the flowering and maturation phases of the coffee tree. Its influence spans three critical stages:

 Flowering: Potassium regulates water movement and enzyme activation, which are
essential for flower initiation and development. Adequate potassium ensures
synchronized and vigorous flowering, setting the stage for uniform cherry development
(1).

 Cherry Set and Expansion: During fruit formation, potassium facilitates carbohydrate
transport from leaves to developing cherries. This nutrient is vital for cell expansion,
sugar accumulation, and overall cherry weight (1). Deficiencies during this stage can
lead to poor fruit set, smaller beans, and increased susceptibility to pests and diseases.

 Cup Quality: Potassium enhances sugar-to-starch conversion and influences the
concentration of flavor precursors such as chlorogenic acids and amino acids (2). These
compounds are critical during roasting, where they transform into the aromatic and
flavor-rich compounds that define Kona coffee’s signature profile.

Please continue to the full report  to learn about the ‘Challenges of Potassium Sufficiency in West Hawaii’s Lava-Based Soils’, ‘How to Know When Your Trees Are Potassium Sufficient’, ‘Final Thoughts’, and ‘References’.

A study by the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) and the Smithsonian Tropical Research Institute (STRI) has found that carbon markets undervalue shade-grown coffee farms. The research, published in Communications Earth & Environment, analyzed 67 studies from around the world’s coffee regions. The findings revealed that coffee farms currently store about 482 million metric tons of carbon in aboveground biomass. However, if all shade-grown farms were converted to sun-grown monocultures, the resulting tree loss could release 174-221 million metric tons of carbon, far outweighing the estimated 82-87 million metric tons that could be gained through global tree-planting initiatives on sun farms. This imbalance points to a troubling incentive problem: carbon credit systems often reward planting new trees but not protecting existing ones. Farmers may be pushed toward replacing older, carbon-dense trees with younger species that store far less carbon. The study also highlights biodiversity risks, as shade-grown farms with diverse native tree canopies support roughly four times more bird species than monoculture systems. The researchers argue that carbon payment frameworks must shift to reward conservation of mature shade trees, not just new plantings.

Kokua Kailua

Sammi Piasecki and Margo Zenk manned the KCFA booth in the August Kokua Kailua Stroll. They enjoyed a successful day giving away coffee posters, selling logo merchandise, and talking Kona coffee with the public.

Study: Farm Level Bacterial Communities Affect Coffee Flavor
https://tinyurl.com/2wx9du8k

“A recent study led by a team affiliated with the Smithsonian Bird Friendly coffee program suggests the bacterial community surrounding coffee plants may have a pronounced effect on coffee flavor.

Published in June in Scientific Reports, the study also establishes a relationship between types of crop management systems — namely full sun or shade coffee — and the bacterial communities on coffee cherries and in the soil.

“Overall, what drives improved coffee flavor is relatively unknown, with likely many complex factors being involved,” the authors wrote. “However, evidence from our study suggests that the bacterial community in the soil and cherries may play a role in coffee quality outcomes.”