The significance of Water activity Curve in Solar treatment of Alida Manor Coffee

Wilford Lamastus, the owner of Alida Manor, talks about sun treatment.

The process of solarization treatment

The so-called sun treatment (Natural process), strictly speaking, should be called "whole berry drying". It is the oldest and seemingly simplest treatment: for more than a thousand years, the principle is to harvest coffee berries, spread them on the ground and dry them, then remove the dried peels / pulp / coffee shells, and then get raw beans, that's all.

But this seemingly simple operation actually has the most complex and difficult-to-control microbial action and flavor products!

Let's start with the role of microorganisms: hundreds of thousands of microorganisms are basically divided into three categories: fungi, bacteria, yeast, etc., and these microorganisms have different preferences for environment and nutrients, such as aerobic / anaerobic, temperature, water activity, carbohydrate types, pH values. It's all different. A single water activity environment, from 0.88 to 1.0, 0.80 to 0.88, and 0.60 to 0.80, can respectively create a favorable environment for these three types of microorganisms (for example, fungi can adapt to the lowest water activity and can move above 0.60; yeast can work in an environment of 0.80 to 0.88, but ordinary bacteria can't!) . If coupled with the supply of large or small amounts of carbohydrates (which can be regulated by the maturity of coffee varieties and berries), and the rate of drying. We can create whether a specific type of microorganism is active or not, and regulate the degree and type of fermentation to a certain extent.

This is why the key factor of "drying rate" is specifically mentioned. Because in principle, the drying rate is the key to the operation of the traditional sun method to regulate the flavor.

Significance of water activity curve

Of course, strictly speaking, Wilford grasps the "water activity curve" of the peel and pulp layer during sun treatment; the first effect of this curve is the fermentation rate: the higher the water activity, the faster the fermentation rate. In addition, this curve will also affect the type of fermentation: different water activity regions are suitable for different types of microorganisms, but also suitable for different biochemical pathways of fermentation. More importantly, the microbial activity promoted and inhibited by the continuous action of this curve from beginning to end determines the transformation of peel and pulp contents and the accumulation of primary biochemical products. Combined with the subsequent chemical condensation reaction, volatilization and infiltration, the flavor of this batch of sun-dried beans was determined.

This seems to be a traditional and basic operation of drying beans, but in fact, there are a lot of details to pay attention to! In fact, many farms and processing plants trying to make excellent sun-cured coffee have been stumped. Friends who have drunk Alida's micro-batches of dried beans the next day must be able to feel clearly that the style and beauty of these batches of coffee are rare all over the world.

Compared with many farmers who prefer to go to the cutting edge to seek a breakthrough, under the trend of investing in anaerobic treatment, Wilford also began his research and a few experiments, but he did not seem to be in a hurry. The editor guessed that his old god had his reason: first learn to walk, then learn to run. If we can not grasp the key of traditional solarization in the regulation of microorganisms, the introduction of more complex new technologies will not bring any advantages. Of course, the editor is also looking forward to what a unique and fascinating taste Wilford, who already knows the key to the regulation of microbes and their chemical reactions, will produce when they officially enter the field of anaerobic fermentation.