Edwin Martinez wrote:
Matthew P. Williams wrote:
......This indicates that washing is an enzymatic, not microbial, process.
you mean fermenting?
I think this is where my confusion lies - it seems like the term fermentation
has been loosely applied to the washing process.
Fermentation is an active process (energy is consumed), while enzymatic activity is passive. Fermentation is an anaerobic microbial conversion of carbohydrates to byproducts like acids or alcohols. Pectinase enzymes, on the other hand, catalyzes hydrolysis of polysaccharides in the mucilage.
There may be historical precedence for the misappropriation of "fermentation": In the same section of the Wintgens book Coffee: Growing, Processing, Sustainable Production
it is mentioned that in the past, Saccharomyces
(brewers yeast belongs to this genus) was sometimes added to washing tanks to expedite the washing process. Adding yeast eventually fell out of favor (I wonder why!!), but this may be the source of the residual misnomer.
Anyway - I'm not at all trying to say that fermentation doesn't occur, I am trying to understand the washing process better, and I have been confused by the interchangeable usage of "washing" and "fermentation". Knowing that enzymes are at play makes me scratch my head when I'm told that fruit is fermented off of the parchment.
Edwin, your post sheds a lot of light on the washing process - I am sure you are intimately involved with it. I'd like to paraphrase the process to see if I am on the right track.
After pulping, the beans are held in tanks, and clean water is added. The beans are soaked until enzymes free the mucilage from the seed. When all the mucilage is off the parchment, washing has reached a critical point: the seed in the parchment is no longer protected by the mucilage layer. If the beans are not washed immediately, they are susceptible to taints from fermentation that may occur in the washing slurry from yeast contaminants fed by mucilage.
Do I understand this correctly?
Mmm, juicy. Tastes like juice. Bean juice.