The science of chocolate

Chocolate is a science, and master it I have not. (Worse, it has prompted flashbacks to grade 11 chemistry, which was and remains the nadir of my academic career.) Working with chocolate requires finesse (of which I have little) and patience (of which I have even less).

The chocolate familiar to many home cooks (chocolate chips, et cetera) isn’t the kind of chocolate with which one can make bonbons, garnishes, and other flights of semi-sweet fancy. Nay, for our purposes, we’re working with couverture, which, by definition must include 30% cocoa butter.  (Chocolate chips are an entirely different formulation, with a much lower percentage of cocoa butter and, often, other emulsifying agents and oils.)

Most of our couverture is supplied by Barry Callebaut (the largest manufacturer of chocolate in the world, and in no way affiliated with the Calgary-based chocolatier of a similar name).  Like wine, couverture is varied, diverse, and often influenced by the region, climate and terroir in which it was grown.

Pre-crystallization (a.k.a., Tempering Chocolate)

Chocolate must first be tempered, or, more accurately, pre-crystallized, before it can be used for moldings, garnishes, and other applications. (Tempering is no longer the preferred term since it is too often confused with temperature, which is merely one aspect of the pre-crystallization process; the other two being time and manipulation.)

To understand pre-crystallization, it helps to have a clear definition of chocolate itself: a suspension of dry particles (cocoa powder) in a fat structure (cocoa butter). Pre-crystallization renders this structure a stable one.

Chocolate, a polymorphic fat (meaning it is changeable) is difficult to make stable because its crystalline structure is so varied. In fact, scientists have identified the following chocolate crystals:

  • Alpha
  • Gamma
  • Beta Prime
  • Beta
  • Beta V
  • Beta VI

Gamma, Beta Prime and Beta are of little concern to us since they are only present when chocolate is in its liquid form. For our purposes, we are concerned with Alpha, and Beta V and Beta VI (a polymorph of Beta V that occurs with time) crystal structures.

Our aim was to create the conditions for the formation of Beta V crystals, which is the most desirable crystalline formation for chocolate work. (Alpha crystals are very unstable; Beta VI crystals, like Beta V, are semi-stable, but less desirable. Beta V crystals have a melt temperature of 34.5C; whereas Alpha crystals have a much lower melt temperature of 27.3C, Beta VI higher at 36.6C.) Chocolate, properly tempered and containing a majority of Beta V crystals, has glossy shine and snap.

There are two methods to pre-crystallize chocolate:

  • Method One (a.k.a., Seeding)
    • Take chocolate to between 40 and 45C, guaranteeing all crystals have melted.
    • Seed the liquid chocolate with already-tempered solid chocolate and agitate to bring the mixture’s temperature down to between 32 and 33C, during which time Beta V crystals from the solid chocolate will mix with the liquid chocolate and aid in its proper crystallization.
    • Method Two (a.k.a., Tabling)
      • As with Method One, take chocolate to between 40 and 45C, set aside 1/3 of the melted chocolate and hold at that temperature.
      • With the remaining 2/3 chocolate, pour onto marble slab and manipulate to bring temperature down to 27C, which forms both Beta V and Alpha crystals.
      • Heat the tabled chocolate to 32C by adding the reserved 1/3, which eliminates the Alpha crystals, leaving only Beta V (because Beta V do not melt until 34.5C).

As is the case with so many things, often the best laid plans can go awry – and the same holds for pre-crystallizing chocolate.  There is such a thing as too many crystals: over-crystallization will make the chocolate too thick, even if it has reached the desired temperature.

Assorted Chocolates

Having become familiar with tempering and basic chocolate work, we progressed to the manufacture of assorted chocolates, including:

  • Dragee
  • Almond Rocher
  • Mint Fondant
  • Rigi-peaks
  • Mint Meltaways
  • Chocolate Truffles
  • Walnut Bonbons
  • Toasted Hazelnut Marzipan
  • Hot Chocolates
  • Blueberry Tea Chocolates
  • Spring Chocolates
  • Coffee Pralines
  • Coconut Rum
  • Knackerli
  • Pina Colada

Along with my partner, I tackled the Hot Chocolates, Coffee Pralines and Mint Fondants (more commonly known by their trade name, Peppermint Patties).

The Hot Chocolates were particularly challenging, since they involved a number of steps: making a layer of cinnamon marshmallow (not nearly as mysterious as I had thought: glucose, air and gelatin); a layer of ganache; a layer of tempered chocolate (serving as the “foot” or base for the pieces when it comes time to enrobe them); and a final, enrobed coating of tempered chocolate.

At each stage, the layers had to set before the next could be applied. And in the case of the final, enrobed coating, care had to be taken when dipping each piece in the chocolate to ensure a vacuum was created (eliminating air bubbles beneath the outer coating – accomplished by quickly and rapidly dunking the piece in the chocolate) while at the same time allowing only enough chocolate to coat the piece so that it did not run or create a foot once set on the acetate to harden (accomplished by bouncing the piece halfway down the end of the dipping fork, then carefully scraping the bottom of the piece over a piece of piano wire).

We had mixed results with the Coffee Pralines. While the coffee ganache filling was silky smooth and incredibly rich, the milk chocolate shell was, on many pieces, unacceptable. (The milk chocolate had not been properly tempered, thus creating an inferior, even ugly final product.) Nevertheless, it was a valuable lesson in making molded chocolates, which is a time-consuming and delicate process.

First and foremost, the mold must be clean and dry. (Water, even in the minutest amount, will cause chocolate to seize up.) Then, depending on how the top of the chocolate will look, garnish may be placed inside the mold. Once any garnish (be it spackled, coloured cocoa butter or, as in our case, painted coffee beans) are hardened, an initial coating of the desired chocolate must be painted on the inside of each mold to ensure no air pockets or crevasses remain unfilled; then, chocolate is poured into the molds and the mold is inverted and drained of any excess to create the outer shell. The mold should be left, upside-down to allow the shell to harden. Once hard, fillings (in our case, the coffee ganache) can be piped into each shell, enough room at the top of the pieces for chocolate to cover them. Again, after the filling has hardened, more chocolate is poured atop to create the bottoms; acetate is pressed on top and excess chocolate scraped out and away from the mold. Once hardened, and after placed in the refrigerator to allow the chocolate to contract, which aids in their removal, the molds can be emptied of their contents.

The Mint Fondants were a simple, yet delicious item that simply involved pureeing fondant with fresh mint, warming it to a temperature no hotter than 72C, then piping it into molds. Once firmed up, the molds can be lifted away, leaving little minted fondant disks, which are then enrobed in chocolate to create an outer coating.

Among the other chocolates made, a few stood out for their interesting technique or notable method.

The Mint Meltaways (also known by their trade name, Icy Squares) demonstrate an important chemical phenomenon known as utechtiques. Mint Meltaways include both coconut and cocoa fats. Each fat has a different melt temperature. When combined, however, while one might assume the melt temperature of the mixture would be an average of the two, in actual fact, the melt temperature is even lower than the lower of the two fats. This chemical reaction ensures the meltaway is barely firm at room temperature and, once eaten, melts in the mouth almost immediately.

Dragee, like the Minted Fondants, are dead easy, but definitely worth noting since they require almonds be cooked in sugar. This process, similar to caramelizing sugar, differs in that the presence of the almonds actually encourages the sugar to crystallize (undesirable when making caramel). This gives the almonds that distinctly caramelized flavour, while at the same time coating them in crunchy, crystallized sugar. Once cooled, the almonds are tossed in tempered chocolate: the chocolate binds to the nuts and, as the nuts are agitated, hardens, leaving the nuts with a chocolate shell. (The nuts should be tossed three or four times, to ensure the coating is thick enough.) Finally, the coated nuts are tossed in a little cocoa powder to add a little bitterness.

Knackerli, despite the unusual name, are nothing more than chocolate disks onto which any assortment of fruits, nuts or other garnishes can be set. I consider them a welcome addition to any box of chocolates, since they offer a brief reprieve from the richness of other molded delights, and the promise, however false, of some nutritional benefit.

Finally, there are truffles. Long a favourite among, well, almost everyone, truffles are merely ganache, rolled into balls, then coated with tempered chocolate and, sometimes, rolled in a final garnish of nuts, sprinkles or, say, shredded coconut.

  1. Tosin said:

    Hello, what about tempering coloured cocoa butter. i tried making on, i heated the cocoa butter to 40C, reduced it to 27C and then heated it back to 30C yet the cocoa butter stuck on the acetate sheet. Just wondering what i am doing wrong

    • krisade said:

      I do not believe you can treat cocoa butter the same as chocolate; it cannot be tempered. Coloured cocoa butter ought to be used like food colouring, to change the colour of white chocolate. Add a few drops of your coloured cocoa butter to liquid white chocolate, then temper the coloured chocolate as you would normally.

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