CHOCOLATE :: tempering

history : the plant : tempering : chocolate truffles

If you have ever melted chocolate you may have noticed that when it cools and becomes solid it is no longer hard and snappable but often soft and less pleasant to eat. To get chocolate to be that perfect hard, snappable feel that is loved across the world we need to temper it.

Before I get all technical it is useful to know that when liquid chocolate re-solidifies into its solid state the fats in the cocoa butter starts to crystallize.

Uncontrolled crystallization of cocoa butter typically results in crystals of varying size, some or all large enough to be clearly seen with the naked eye. This causes the surface of the chocolate to appear mottled and matte, and causes the chocolate to crumble rather than snap when broken. The uniform sheen and crisp bite of properly processed chocolate are the result of consistently small cocoa butter crystals produced by the tempering process.

The fats in cocoa butter can crystallize in six different forms. The primary purpose of tempering is to assure that only the best form is present. The six different crystal forms have different properties.

crystal melting temp notes
I 17°C (63°F) Soft, crumbly, melts too easily.
II 21°C (70°F) Soft, crumbly, melts too easily.
III 26°C (78°F) Firm, poor snap, melts too easily.
IV 28°C (82°F) Firm, good snap, melts too easily.
V 34°C (94°F) Glossy, firm, best snap, melts near body temperature (37°C).
VI 36°C (97°F) Hard, takes weeks to form.

Making good chocolate is about forming the most of the type V crystals. This provides the best appearance and texture plus they are the most stable crystals so the texture and appearance will not degrade over time. To accomplish this, the temperature is carefully manipulated during the crystallization.

The chocolate is first heated to 45°C (113°F) to melt all six forms of crystals. Then the chocolate is cooled to about 27°C (80°F), which will allow crystal types IV and V to form (VI takes too long to form). At this temperature, the chocolate is agitated to create many small crystal "seeds" which will serve as nuclei to create small crystals in the chocolate. The chocolate is then heated to about 31°C (88°F) to eliminate any type IV crystals, leaving just the type V. After this point, any excessive heating of the chocolate will destroy the temper and this process will have to be repeated.

Two classic ways of tempering chocolate are:

  • Working the melted chocolate on a heat-absorbing surface, such as a stone slab, until thickening indicates the presence of sufficient crystal "seeds"; the chocolate is then gently warmed to working temperature.
  • Stirring solid chocolate into melted chocolate to "inoculate" the liquid chocolate with crystals (this method uses the already formed crystal of the solid chocolate to "seed" the melted chocolate). It is this method that hipo hyfryd chocolatiers use.

Some of the text and the images were extracted from Wikipedia. All text is available under the terms of the GNU Free Documentation License.