Homemade and small scale chocolate making has followed an arc similar to the beer industry where a "golden age" declines through consolidation to industrial dominance from which an "artisan" resurgence grows. In the early 20th century there were a relatively large number of chocolate makers where most of them were small-scale producers. As the century progressed, a number of factors drove the industry to consolidate where essentially all the small-scale makers were bought, or they went out of business. The global industry today is dominated by the "big five": Hershey's ® , Mars ® , Ferrero Rocher ® , Cadbury ® , and Nestlé ® . However, over the last 15 or so years, a number of small but dedicated "bean to bar" chocolate makers have been springing up .

The key to high quality confectioner chocolate is the size of the fat crystals in the final product. If the crystals are too large, the chocolate is too grainy, and if they are too small, they accumulate too much fat and the product is slimy or slick. Although chocolate contains basically two ingredients (cocoa nibs and sugar), it requires some specialized equipment to fully process. There needs to be a process to get the fat crystals down to less than 30 microns, and often times there is an additional refinement step known as conching to develop the desired flavors and textures. An old method to reduce the crystal size to the desired size, which is not used by large-scale producers, is the use of a malangeur, which is essentially a stand mixer where the mixing blade is replaced with two big granite rollers.

The Charlie Papazian for the current chocolate resurgence is John Nanci, who is responsible for bringing chocolate making to the home hobbyist by introducing inexpensive countertop melangers. Melanging and conching both mix and aerate, and melanging does generate heat, but not as much as that used in the conching process. After more than 100 years it is still not clear the relative importance of conching and how much of its role can be duplicated only with melanging.

Caitlin Clark and colleagues at Colorado State University looked to address the question of the effect of time and temperature on the quality of finished chocolate when using these small-scale melangers and they summarized their findings in a Nature Scientific Reports paper. Of interest to the home chocolate maker, they found that melanging results in very similar flavor outcomes as conching when used to refine chocolate and that the final flavor of chocolate made in a melanger is far more dependent on time spent in the melanger than on the temperature of the chocolate system.

From the data presented here, one might predict a flavor progression in the samples from time point to time point. Chocolate pulled from the melanger at 8 h would be dominated by floral and fruity notes. Allowing melanging time to continue up to 16 h would bring out a more roasted, toasty, and nutty flavor profile with rancid or sweaty undertones. A melanging time of 24 h would offer a well-rounded profile with compounds from a number of different chemical and flavor classes represented. However, further testing is needed to confirm this prediction. Sensory tests may illuminate interactions between compounds that cannot be predicted by metabolomics data alone.

Incidentally, when doing some background research for writing this summary, I found that this article is a writeup of her Master's thesis on this topic, which contains more information that was not included in the scientific paper.

Clark, C., Bettenhausen, H.M., Heuberger, A.L. et al. Effects of time and temperature during melanging on the volatile profile of dark chocolate. Sci Rep 10, 14922 (2020). DOI: https://doi.org/10.1038/s41598-020-71822-0