Superheated Solution for Processing Cascara
This is what normally happens to cascara; It is shot out the back of the coffee mill, dried, and used for compost.
By Dan Bolton
Sourcing cascara is not for amateurs, observes Nanelle Newbom, a veteran San Diego coffee roaster and buyer with 14 years’ experience in specialty coffee.
“Literally if you don’t know your mill and carefully learn the process and communicate clearly you could end up buying the top layer of a compost pile that got somewhat sun-dried,” she says.
“But if you do your job you could find really clean, dried fruit that has been carefully processed and tastes amazing,” she adds, “It’s not for amateurs (yet).”
ALSO: Now is the Time for Cascara
David Seminsky, a China-based entrepreneur who founded Sumerian Coffee, (www.sumeriancoffee.com), understands what a pain it is for farmers to meet roaster requests for quality cascara – especially if those roasters want to dig on price. The product has great potential but processing is difficult, he explains.
“Oxygen is the enemy when it comes to food. It makes food more susceptible to microorganisms that create pathogens - bacteria. This is why farms have been challenged to broadly distribute cascara. After the seed has been de-pulped, ideally the pulp needs to be dehydrated within 24 hours.
Photo courtesy David Seminsky
Superheated Solution for Processing Cascara
Superheated steam dehydration equipment, like that pictured above, is being modified to process and dry cascara.
Seminsky, who spends his time developing ways to impact the coffee value chain through innovation, discovered a firm that builds equipment for NASA is developing a superheated steam dehydration system to process coffee pulp.
“Why is this a revolutionary innovation for coffee? How do you dehydrate with steam? Seems counterintuitive?” he asks excitedly.
“This is what coffee innovation looks like,” writes Seminsky
“Steam that boils from your cup or a pot at 1000 C is saturated. Superheated steam is anything above that temperature. It’s a law of thermodynamics that steam doesn’t like to be above 100o C. It likes to remain at saturation. When heated above 100o C steam looks for ways to return to saturation,” Seminsky explains. “Thus if you have a closed vessel filled with steam at a temperature of 140oC and you add biomass ― in this case, wet coffee cherry pulp ― it will extract the moisture from the pulp in its attempt to return to 100 o C. It dehydrates and sterilizes with zero exposure to oxygen. The polyphenol TAC (total antioxidant capacity) is optimized.”
The process under development can transform 1 metric ton of pulp into 100 kilos of cascara every 45 minutes. The system also captures the steam extracted from the pulp and re-condenses it into water that can be used for cooking, cleaning, at the washing station, and potentially even as drinking water.
The dried weight of pulp is approximately 10% of the total mixture. “Imagine, if you start with 1,000 kilos of wet pulp, normally destined for compost, you will end up with 100 kilos of cascara and 900 liters of clean water,” says Seminsky.
“Yes, I know. It’s amazing,” he said.