Post-harvest processing for reduction of bean bitterness
Posted in: Tech Help, Tips, Tricks, & Techniques
I am looking to amass as much detailed information on post-harvest/fermentation techniques as I can get my hands on. I am particularly interested in any stages of the process that might be used to reduce bitterness in the processed beans.
I am currently sourcing my beans from a grower in Sarawak, Malaysia. He grows a range of high yield genetic strains in his sun plantation (over 10 types from places all over the world including Ghana and Brazil). He harvests pods on day 1 of his cycle, splits pods on day 2 and leaves in baskets, he begins a 3 box fermentation on day 3 (shifting beans from box to box after 40 and 80 hours). He halts fermentation at 120 hours, briefly washes in a bucket and then sun dries over 3-4 days if the weather is good.
Would more frequent aeration in the later stages of fermentation reduce bitterness? Would a longer period of pre-drying before fermentation be useful? More pod storage? Better insulation of fermentation boxes to reach higher peak temperatures? Should the microbial fauna be kickstarted with additions i.e. sourdough starter etc?
I have read some vague descriptions of an interesting bag fermentation process being used by the Camino Verde farm in Ecuador. The sources imply that it yields very good flavour results from basic high yield varieties. Does anyone know the details of this approach?
Any assistance at all with these questions would be greatly appreciated!