The by-products of coffee processing are mainly coffee pulp, parchment husks and coffee husks. The main environmentally sustainable alternative uses include soil conditioner, fertilizer, mulch, animal feed, alcohol, bio gas, charcoal, heat energy, wax, and acids.
Coffee chaff from coffee roasting and spent coffee grounds from coffee manufacturing can also be used as CO2-neutral fuels. Spent coffee grounds from soluble coffee production can be burned as renewable fuel which replaces or reduces fossil fuel use for other production stages.
Four common sustainable coffee by-products include the following,
- Coffee pulp is a rich source of nutrients: 0.5% nitrogen; 0.15% phosphorus, and 0.5% potassium.
- Coffee pulp can be treated and used as organic fertilizer.
- Usually the coffee pulp is placed on piles and left to compost for about 3 to 12 months.
- During that time, coffee pulp turns into rich, black humus excellent for composting.
- Using organic fertilizers improves soil conditions and increases agricultural yield.
- Farmers save money otherwise spent buying inorganic fertilizers.
Mushroom planting soil
- Coffee pulp can also be used as planting soil for mushroom production.
- When used for this purpose, the coffee pulp is fermented for about two days.
- The coffee pulp is then pasteurized with hot water, drained, dried and mixed with mushroom spores.
- Next, the mixture is put in plastic bags with holes where the mushrooms develop for about 3 to 4 weeks.
- When the mushrooms grow out of the holes, they are collected.
- One bag allows for about 2 to 3 mushroom harvests.
- The fresh mushrooms are for table consumption or they can be dried for sale.
- The income from mushroom growing can be significant for the farmers who do this.
Animal feed supplement
- Coffee pulp is very rich in nutrients.
- Coffee pulp can be dried and used in animal feed.
- The pulp needs to be treated as quickly as possible to prevent the development of fungi.
- Usually, coffee pulp is treated with calcium hydroxide and dried under pressure.
- Another way to dry pulp, in the absence of industrial equipment, is to mix the coffee pulp with sugar cane molasses or other inorganic substances before storing the mix in silos.
- The resulting silage is available for use after 3 weeks and can remain stored for up to 18 months.
- The use of coffee pulp for this by-product appears to offer limited value because the cost of processing the pulp can exceed the gain derived from its use.
- The research on the effects of caffeine, potassium and other natural chemicals in the pulp on the health of animals is ongoing and will be influential for the future of this by-product.
Energy source for heat exchangers of coffee driers
- The most energy consuming step in coffee processing is drying.
- Sun drying is very common and offers many benefits but has drawbacks as well.
- Sun drying conserves energy, minimizes the use of fossil fuels and reduces costs.
- However, parchment coffee can be contaminated with dust and dirt during the sun drying process.
- Rainstorms happen without warning and are a challenge for farmers to prevent bean re-wetting which can promote bacterial infections and moldy growth.
- Because sun drying is time intensive, many coffee processors choose mechanical drying. The downside is that the cost to operate mechanical dryers is high and can cut down on margins.
- Using coffee parchment husks as the energy source for burners for heat exchangers of coffee driers is both a great environmentally friendly waste-recycling and energy-saving solution.
With international markets changing and the economic pressures mounting everywhere, crops such as coffee require innovative thinking to improve efficiency, cost effectiveness, quality and competitiveness. Sustainable coffee by-product development will continue to be a fast growing and important field of research.
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Timothy (“Tim”) S. Collins, the author, is called by those who know him “Gourmet Coffee Guy.” He is an expert in article writing who has done extensive research online and offline in his area of expertise, coffee marketing, as well as in other areas of personal and professional interest.
Come visit the author’s website: http://www.ourgourmetcoffee.com
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