Part 1 : Cocoa Butter

Several weeks ago, I gave a tour to a group of chocolate enthusiasts. Our conversation quickly progressed from a general beginners’ overview to an in-depth discussion of our farmers’ fermentation process, terroir, genetics, Dandelion’s roast profiles, and tempering.

Tempering is a tricky subject. When I began working at Dandelion Chocolate, tempering was the most intimidating step of the process for me. What exactly is tempering? My cookie cutter answer usually goes something like this:

Tempering is a process in which we raise and lower the temperature of chocolate to allow crystals to form. Certain crystals form a structure that results in a shelf stable chocolate with a shiny sheen, nice snap, and smooth texture. Crystals in this stage are known as Form V crystals, and they provide the foundation for well-tempered chocolate bars.

Credit: Laurie Frankel

Usually, people are satisfied with this answer. It’s short, simple, and glosses over some complicated details; not so for this tour group. At the end of the tour and another round of insightful questions and comments, one woman asked, “What and how exactly is the crystal structure formed in a well-tempered chocolate bar?”

I looked at her blankly because I didn’t know the answer, and I wasn’t entirely sure what she was asking. Did she want me to draw the crystal structure showing the carbon bonds that symbolize chocolate? Was she asking what kind of crystals are required? Her question and my inability to answer it at the time prompted me to do some digging. The following is what I have interpreted from various textbooks (yes, textbooks!) on chocolate.

The first step to understanding tempering is to understand the cocoa bean. Cocoa beans are made up of about 50% cocoa butter and 50% cocoa solids. Cocoa butter is a natural fat present in cocoa beans, and is integral to tempering due to its ability to crystallize, or to form crystals, at different temperatures. The crystalline structure of cocoa butter is what determines the appearance and texture of chocolate.

Cocoa butter crystals can pack themselves (molecularly) into six forms. Each crystalline form has a different melting point and the higher the form, the higher the melting point. In other words, Form I has a crystalline structure with the lowest melting point (16°-18° C) while Form VI’s structure has the highest (34°-36° C). The various crystalline structures make chocolate appear different to the casual observer.

While our chocolate bars are tempered into Form V, other unstable crystalline forms can be found throughout Dandelion’s chocolate making process. These unstable forms usually result in an uneven appearance–light brown spots or pale surface swirls on the chocolate, for example. These spots and streaks are known as bloom, and they appear due to a natural separation of unstable cocoa butter crystals from cocoa solids. Untempered, bloomed chocolate breaks apart easily, but is still edible and tasty. In fact, we eat it all the time for quality control. So, why do we temper chocolate?

Bloomed chocolate is easier to break apart (sort of).

The most important reason is to keep chocolate shelf stable. Form V chocolate contains the most stable cocoa butter crystals due to the fact that they won’t melt until 85°F/29°C – which is well above external body temperature. This crystalline structure allows our chocolate bars to retain their glossy sheen and shape when they are stored in a cool, dry place. Dandelion Chocolate’s bars can usually be kept in this condition for up to a year. Shelf stability is also the reason why many chocolatiers temper chocolate for their bon-bons and truffles.

At Dandelion, we use a continuous tempering machine designed and built by FBM Boscolo, the Unica. This machine allows us to control the temperature of the chocolate in three different steps – but we only use two. First, we raise the temperature of the chocolate to 50°-54° C in order to melt away any crystals that may have formed. Then, we lower the temperature and agitate the chocolate to encourage the development of a Form V crystalline structure. Done correctly and with some time, Form V chocolate will contract from our mold as it cools, leaving us with a beautiful, shiny, dark chocolate bar.

Stay tuned: In the next post, I will write about other factors that affect the tempering process.

References

Minifie, Bernard W. Chocolate, Cocoa, and Confectionery: Science and Technology. 3rd ed. Gaithersburg, Maryland. 1999. Print.