Refining and Conching: Unlock the Bean’s Potential

From by Institute of Culinary Education
Refining and Conching: Unlock the Bean’s Potential

By Michael Laiskonis—ICE Creative Director


The final steps in processing our bean-to-bar chocolate make up the longest phase of the manufacturing process—a waiting game where the true essence of the bean, its complex flavor and its silky texture are unlocked. At this point, we focus on physically breaking the bean's coarse texture, revealing subtleties beneath its bitter astringency and liberating its cocoa butter. Though we add ingredients at this stage, there is also an aspect of elimination—the refining stage is followed by conching, which peels away unwanted volatile flavors.

Sifting the Finished Chocolate


My last post dealt with handling the roasted bean—crushing it into nibs, separating its shell, grinding it into fluid cocoa liquor and extracting pure cocoa butter. During this final stage, the chocolate maker faces the challenge of tasting a bean's full potential and identifying the subtle nuances within. While the goal of the “craft” chocolate maker working primarily in single origin batches is often to enable the expression of that bean's inner essence, an industrial manufacturer's typical aim is to create consistency from batch to batch, from year to year. Neither approach is qualitatively better or more difficult—just two possible approaches employed in the final stage of chocolate making.


Different kinds of machines can carry out the task of refining (stone melangeurs, roller refiners, scraped-surface refiners, etc.). In the lab, our coarse chocolate liquor enters a 10-kilogram capacity ball mill—a temperature-controlled tank that contains roughly 60 pounds of hardened steel-grinding media (ball bearings, essentially, in two sizes). With agitation, the steel balls begin breaking down the fairly large particles in the liquor, refining them down to a target of around 20 microns—in terms of scale, one micron (µm) is one-millionth of a meter (or one-thousandth of a millimeter). More accurately, true particle size in chocolate will lie along a curve, or a distribution, some smaller and some larger than our target. Looking closely at the structure of chocolate, it is simply very small solid particles (cocoa solids, sugar and sometimes milk solids) dispersed in fat—cocoa butter. Because the threshold of perception of a particle on our palate is in the neighborhood of about 35µm, a smooth, creamy mouthfeel depends upon breaking down the solids below that mark. Particles that are too small (below 15µm), however, will create too much surface area for the available cocoa butter, thus adversely affecting the flow properties of the chocolate with increased viscosity.


Keep reading to learn more about this vital stage in the chocolate making process.