Testing sugar content in cacao

Cacao staff at BFREE are learning to harvest cacao pods when they are the sweetest. Last month, Elmer Tzalam and Mark Canti harvested cacao pods to test sugar content at different stages of ripeness. They carefully opened each pod one at a time. Then they scraped out several beans and place them in a mesh bag. They squeezed a few drops of juice from the bag onto a tool called a refractometer. Finally, they held the refractometer to their eye and looked into the direction of a bright light source. As a result, they received a reading of “degrees brix” which is the sugar content of an aqueous solution. 

One degree Brix is 1 gram of sucrose in 100 grams of solution and represents the strength of the solution as percentage by mass. Brix Refractometers are built to measure the sucrose content of a sample through refraction. These meters are capable of incredibly quick and accurate results and are used often in the food and beverage industries. 

The wild, heirloom criollo cacao at BFREE has never been grown in a farm setting. Therefore, the data we collect is new information to the cacao industry and is part of our efforts to characterize this ancient heirloom fine flavor variety. By using tools like the refractometer, we will begin to better understand the most desirable moment to harvest a pod.

Additional info about how Brix refractometers work

Traditional refractometers are handheld analogue instruments. They are held up to the light, so that it shines through the sample. The light is then directed through a prism and lenses onto a measurement scale. A shadow will be case on the measurement scale at the angle where total internal reflection occurs. Observing this shadow through the eyepiece gives the brix reading.

A special thanks to Skyler and Austin from the visiting ARRC group for their enthusiastic participation in this process.

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