Water and coffee: Processing

To process green coffee to the stage ready for roasting, it needs to be fermented to remove all the mucilage from the bean. Mucilage is the sticky, fruity part which is between the skin and bean, it is a little like grape, but only a very thin layer between bean and skin.

Coffee is generally either processed ‘natural / sun dried’, or ‘washed’. For washed coffee, once the cherry has been picked from the tree, within 6 hours it needs to be pulped to remove the skin, and soaked in water to ferment. In that first 24 hours the mucilage is disolved, it then needs to be dried in the sun for between 5- 9 days to reduce moisture levels to between 10.5 – 11.5% which means it can safely sit for a year ready for roasting.

washed coffee ready for floaters to be removed

In countries where water is short, or for reasons which natural coffee is wanted, coffee is not water fermented, but dried in the sun in the cherry form. Once the cherry is picked from the tree, it is put straight onto raised beds to dry in the sun as a cherry, this may also take a week to dry.

Washed coffee is often dried on concrete patios, but natural coffee is usually dried on raised beds to allow air flow under beans.

Part of the water processing is floating the cherries in water, the good sink and the under / over ripe cherries, and sticks etc all float and are scooped off and discarded. This process removes a lot of defects, so washed coffee will inherently have a lower defect count then natural coffees, putting washed coffee in a higher quality level.

Once the coffee is washed, there is a lot of water which has all sorts of contaminants left in it from the coffee, which poison rivers, killing marine life due to changes in ph level etc.

 

Research and industry development has produced methods of cleaning the water which can be done at local processing plants with manageable installation costs. Small processing plants may be build by co-ops throughout the region of their farmers, to reduce work for farmers, give better control over quality through access to proper machinery, and to reduce their environmental impacts. These processing plants may have water cleaning facilities depending on the size.

Water treatment method used by PRODECOOP in Nicaragua:

3 steps are used here to process the water: physically, chemically and biologically.

PRODECOOP Esteli, Nicaragua 2009. Wet mill with water treatment plant under construction.

Physically: Once the coffee is washed it is removed from the water, and the water is put in tank 1 for a while to allow large particles to settle, the top of the water is then drained to tank 2 leaving the ‘scum’.  Water left in tank 1 evaporates under the clear roof , and the dry muck is scooped out and used as organic compost.

Water settling tank 1, with pipes to feed Calcium hydroxide.

Chemically: next Calcium hydroxide is used which further separate sediment from good water, and is separated again.

Biologically: finally the water is pumped to run down a rough ramp with jagged stones protruding, this agitates the water creating turbulence and mixing water with oxygen. The water is cycled over the ramp more than once to finish the cleaning, and ph levels are  acceptable, it is then reused or put back into river.

the treated water is pumped from tank 2 to run down the ramp

Pollution of rivers is a big problem in coffee producing areas, as many different coffee farmers spread for miles will be reusing the same river water as it runs down the mountain. Co-ops can play a key role in increasing production efficiencies and best practice as they hold a collective responsibility on behalf of locals, and have resources to build processing and water cleaning stations.

Another good reason to buy from co-ops.

Do Micro Lots matter to Producers

Remarks from the SCAA lecture about ML’s

On the pannel there was a spead of industry people; co-op members, brokers, roasters, researchers.

+if you only buy a ML from a producer and not their normal harvest this is NOT seen as good practice in “relationship trade” (by some producers) its like only going out for dinner with a friend when they are shouting dinner.

+Skimming the best out, on the whole doesn’t greatly reduce the quality of the main harvest, rather- that the good quality beans are missed in the cup when left in normal harvest, so skimming can be a good way of achieving a special lot, esp when already harvested or harvest special lots at “optimum picking time”.

+Farmers (from CENFROCAFE in Peru) who attained a ML once never received it again, seemed like luck to them. This brought about big disappointment. They have often had to re-blend ML’s back into normal coffee as they had no buyers. It was mentioned that farmers (in private) like the idea of ML’s- its the co-op who mainly talk about jealousy among producers.

+In peru, ML are seen as a seperate business, requires farmer to file tax return (which the co-op would normaly do) this is also on a higher tax code and rate, and requires accountant. Also land lots which have produced ML’s are seen as more valuable so land tax and value go up too.

+everyone wants to taste samples of ML’s, but few actually buy.

+Roasters are creating (perceived) demand for ML’s, not lead by customers or market.

+ML’s can be useful for producers to develop a “new” flavour profile to meet a market, and apply these agronomic practices to main crop. (To me this seems like the best role of ML’s -develop best practice at micro level, test it on market, and roll out macro level if successful)

+There is a need to increase confidence between producers and roasters, conducting dialog and questions around adding value and ways to make ML’s work for farmers is very important as ML’s increase in trade.

Peoples Coffee has held off from pushing for ML’s from our producers due to the feedback we get when raising this topic. It is a lot of extra work for farmers and the co-op to produce, and outside of the COE auction system- it’s hard to find buyers to pay what the farmers would like to receive for all the extra work.

However some of our producers are now offering special lots which may be skimmed or ML’s, which we will be receiving later in the year !! (july 2012??)

I think it is more beneficial to raise quality of total harvest, rather than focus on ML’s which only see a few mouths. Then, when we talk about quality it is relating to our bread and butter coffee, not the ML’s which make up 0.1% of business. This issue is frustrating when other roasterys talk about buying the highest quality coffee for high prices, but it only relates to 0.1% of their business as ML’s. (Stumptown is often mentioned in this capacity)

René