Barista Magazine

Apr-May 2012

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environment clean and keep the coff ee from developing off -fl avors. Once the coff ee is deemed ready for washing, it is generally sent through channels of water where the coff ee is washed clean of its mucilage. In Ethiopia though, the coff ee does not go immediately to be dried. It is generally sent to another tank for post fermentation soaking. In this tank coff ee will spend another 12 to 24 hours (sometimes longer) under clean water. EXCEPTIONS I am unaware of any coff ees being processed in eastern Ethiopia using the washed method, so that is a diff erent coff ee altogether. In the southwestern regions of Ethiopia though, 72 eco-pulpers have been installed which are not compatible with this wet fermentation process. I have also seen, depending on a river's contamination, washing stations using dry fermentation, but it is rare. I have also heard about and seen a few producers in Latin America, Uganda, and even certain areas around Lake Toba (Dolok Sanggul in particular) in Sumatra that use wet fermentation. But again, this is rare and usually for shorter timeframes, and typically without post fermentation soaking. SUMMARY Fermenting the coff ee in water for 48 to 72 hours, washing, soaking in water for 12 to 24 hours, and then sending it to be dried. FLAVORS Of all the processing techniques, wet fermentation really stands out, as it is likely the most diff erent. T e real question that comes to my mind is how much fermentation is really going on, or is it really just the pH and solvency of the water that eventually deteriorates the mucilage enough to be washed off ? T e reason this comes to mind is that wet fermentation, in my experience, produces a very clean and transparent cup. Lighter tones tend to be accentuated, and acidity tends to be moderately high but somehow also rounded. I oſt en notice in this process that green or vegetal notes can also become very clear. T inking particularly of Ethiopia and the coff ees around Dolok Sanggul in Sumatra, these coff ees are prone to showcasing a green tea note, or even a minty quality. Some even go as far as a raw, nutty, savory, or peppery quality, begging the question: is transparency always what you want? Of course, sometimes that clear, transparent cup is simply amazing and helps to defi ne that coff ee. DOUBLE FERMENTATION—KENYA PROCESS WET FERMENTATION—ETHIOPIA PROCESS Ethiopia seems to always deserve its own special category in the world of coff ee, and the washed process that was born in the 1950s in Yirgacheff e is no diff erent. While other places practice wet fermentation, there is simply no other place in the world like the south of Ethiopia where I have seen such a regionally defi ning processing practice that is as unique as it is extensive. As you might have assumed it can all be summed up with one word: water. Water is not the fi rst thing that generally comes to mind when people outside the coff ee world think of Ethiopia, as they tend to think of the dry eastern regions of Ethiopia. But in the south, it is lush and green and water is used more extensively than anywhere else I have ever seen when they are processing washed coff ee. Regarding the process itself: aſt er pulping, the coff ee goes into concrete tanks that are then fi lled with water for the coff ee to ferment in. Not only does the water cool the environment that the coff ee is fermenting in, but it also serves to slow the reactions that cause the mucilage to break down. T is combined with high altitude (i.e. cool temperatures) all results in fermentation times that generally range from 48 to 72 hours. During those 48 to 72 hours, the fermentation water can also be changed multiple times, which slows the process more, but the intention is to try to keep the 44 barista magazine Kenya is known in the coff ee world for its extreme dry fermentation times. While Kenya does have longer dry fermentation times than any other country I have visited, the fermentation times have actually been shortened in recent years due to the recirculation of pulp water. T e recirculation of used pulping water so it can be used again for more pulping adds more enzymes, bacteria and sugars, and likely changes the pH of the water, therefore speeding up the time it takes for the mucilage to break down. Before this recirculation became common practice, I was oſt en told dry fermentation times could go up to 72 hours. Today, while not all places recirculate the water, many do and the average fermentation times recorded particularly around Nyeri are between 18 and 48 hours, with 30 being a good average. Getting to the process itself: coff ee is pulped and then put into a fermentation tank overnight. T en it will either be taken out the next aſt ernoon and washed clean, or it may be leſt in that tank, or moved to a secondary tank for another day of fermentation. All of this is done without water being used except to move the coff ee from one tank to another. Once the coff ee is ready, it is washed and sent to a post washing soak tank where it will be soaked for 12 to 24 hours (or sometimes longer). SUMMARY Dry fermentation for 18 to 48 hours (30 hour average), washing. T en 12 to 24 hours of post fermentation soaking. T en sent to be dried.

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