Agri Evolve’s yeast fermentation process

Step 1

The amount of yeast to be used is calculated based on the weight of the coffee being fermented: 1kg of coffee cherries or pulped coffee = 1g of yeast

Agri Evolve’s standard batch is 5MT of coffee and 5kg of yeast. It is also important that the cherries used are of a high quality (fresh and ripe).

The yeast strain used is Saccharomyces Cerevisiae.

Step 2

The amount of water to be used is calculated based on the amount of yeast being used:

1kg of yeast = 10 litres of drinking water

Since Agri Evolve’s standard batch uses 5kg, they require 50 litres of drinking water.

Step 3

The water is now fed into a container at a temperature between 25 and 37 degrees celsius.

Step 4

Next the yeast is added, stirred gently, and left to stand for 10 minutes, when it is stirred again to break up any clumps.

Step 5

This mixture will be left to stand for another 10 - 20 minutes, at which point the temperature of the mixture, as well as the temperature of the coffee to be fermented must be taken. These temperatures should not exceed 10 degrees celsius.

Step 6

It is recommended that, for volumes of coffee exceeding 1MT, the mixing of yeast solution and coffee is done in stages.

For their standard batches, Agri Evolve starts with a tank of 2.5MT coffee. To this they add half of the yeast solution, then stir gently to combine. Next they add the remaining 2.5MT of coffee, and stir in the second half of the yeast.

Step 7

The coffee will then be left to ferment for 72 hours, following which the liquid is drained, and the fermented coffee is taken out to dry on raised sun drying beds.