We read some things about coffee that are worth noting in a post on Daily coffee news’ site: More from ASIC Portland on the cutting edge of coffee science. We asked if we could re-post some of the facts there, but got no response. So if this post is suddenly removed sorry.
Degassing of Roasted Coffee
Presented by: Dr. Samo Smrke of the Zurich University of Applied Sciences.
Dr Samo’s research included extensive work on degassing of roasted coffee, quantifying some anecdotal data:
- Dark roasted coffee degasses more than light.
- Fast roasts degas more and more quickly, and even after long term whole bean storage, a small amount of CO2 is still accessible once the coffee is ground.
- Aged coffee has a faster flow rate as espresso than fresh roasted.
- High temperature storage environments have a massive impact on freshness. In an extreme example: 70 days of resting at -25°C was roughly equivalent to two days at 35°C . Interestingly enough, oxygen was not observed as a significant staling factor at temperatures below 15°C.
Brewing and Roasting Science
Some interesting research in general brewing and roasting science was reported by various parties during the course of the symposium, and here are some highlights:
- André Eiermann, the 2017 Swiss Barista Champion, presented some research indicating that factors like higher dose, finer grind, and darker roast can increase the TDS of a capsule-brewed coffee, and that higher extraction time might correlate to lower acidity ratings. Some of his findings contradict some old, more informal data analysis I performed relating extraction and roast level.
- Claudia Passos hypothesized that spent carbohydrates from coffee brewing could be used as a delivery mechanism for medication taken by an inhaler.
- Scott Frost from UC Davis suggested that the pulsing cycle of a coffee brewer can have a dramatic effect on extraction, where shorter, more frequent cycles increase extraction.
- Dr. Jean Xavier Guidard of UC Davis noted higher TDS and more consistent results from conical shaped brewers as compared to flat bottom baskets, and that basket shape is more important than small grind adjustments in extraction.
- Mackenzie Batali of UC Davis offered insights on extraction data, noting that 50 percent of coffee is extracted within the first 200mL of brewing. A doctoral candidate, Ms. Batali mentioned she’d referenced Sandra Elisa Loofbourow’s similar analysis for Royal in her research!
- Keiko Iwasa from Suntory was able to trace some important contributors to coffee flavor, particularly fresh fruity aromas, to esters formed in roasting, themselves a result of Methanol, also formed during roasting, indicating that many of the flavor compounds we appreciate are not present at all in green coffee, but must be drawn out in the roast.
- Ralf Zimmermann of Probat demonstrated that light roasts contained the highest amounts of antioxidants in his study.
- Samuel Lopane of Clemson University was able to demonstrate that the shelf life of cold brew need not be limited by microbial activity — of which none was detected — but rather should be determined by sensory changes. He also noted that the rise in popularity of cold brew is almost certainly linked to the ability for consumers to take home specialty coffee without having to worry about how to brew it.
Additional items discussed
The rest of the article details science and studies on Plant Sceince and Pathology. Read the full post here: More from ASIC Portland on the cutting edge of coffee science.
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