Long-form coffee science articles grounded in peer-reviewed research.https://jayarr.coffee/deep-brew/https://jayarr.coffee/deep-brew/research/aroma-staling-kinetics/https://jayarr.coffee/deep-brew/research/aroma-staling-kinetics/Coffee's most potent sulfur odorants are also its most fragile. What studies measured in whole beans, ground coffee and brewed coffee, how fast each loses aroma, and why.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/chlorogenic-acid-cascades/https://jayarr.coffee/deep-brew/research/chlorogenic-acid-cascades/Chlorogenic acids are coffee's main phenolic compounds, and roasting breaks most of them down into the compounds behind much of its bitterness. This note sums up what the research shows.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/coffee-climate-change-data/https://jayarr.coffee/deep-brew/research/coffee-climate-change-data/How climate change is affecting coffee in Brazil, Vietnam, Colombia, Ethiopia, Indonesia and Central America: heat, robusta's sensitivity, suitable land and recent harvests, with each figure dated.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/cultivar-roast-profiles-hoos/https://jayarr.coffee/deep-brew/research/cultivar-roast-profiles-hoos/Rob Hoos sorts Arabica cultivars into four groups by how they like to be roasted. What his book Cultivar (2025) recommends for each, how he hedges it, and how to use it on a first roast.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/espresso-physics-darcy-law/https://jayarr.coffee/deep-brew/research/espresso-physics-darcy-law/How Darcy's law describes water moving through an espresso puck, why flow rises only with about the square root of pressure, and what measured puck resistance shows about puck prep.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/extraction-sequence-explained/https://jayarr.coffee/deep-brew/research/extraction-sequence-explained/Coffee's compounds dissolve at different speeds, so taste changes as extraction rises. What measurements show about what comes out first and last, and where the sour-sweet-bitter story breaks down.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/flavor-volatiles-oav-guide/https://jayarr.coffee/deep-brew/research/flavor-volatiles-oav-guide/Roasted coffee holds about a thousand volatile compounds, but a few dozen carry its aroma. How odor activity values rank them, what omission tests showed, and where the ranking fails.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/maillard-caramelization-strecker/https://jayarr.coffee/deep-brew/research/maillard-caramelization-strecker/Roasting browns coffee through three linked reactions: the Maillard reaction, the Strecker degradation inside it, and caramelization. This note covers what each makes and what roasters can steer.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/melanoidins-body-color-health/https://jayarr.coffee/deep-brew/research/melanoidins-body-color-health/Melanoidins are the brown polymers roasting makes. What studies show about how much coffee holds, how roast changes them, and their roles in color, crema, body, staling and health.Thu, 12 Mar 2026 00:00:00 GMThttps://jayarr.coffee/deep-brew/research/sweetness-paradox-roasting/https://jayarr.coffee/deep-brew/research/sweetness-paradox-roasting/Roasting leaves very little sugar in coffee, yet a good roast can taste sweet. The research points to aroma and to less sourness and bitterness; sugar itself may matter only in the lightest roasts.Thu, 12 Mar 2026 00:00:00 GMT