Chocolate Heat Treating

This time of year is filled with lots of holiday cheer and many traditions that run throughout generations year after year. A common tradition for many is baking delicious treats to share with others during this season of giving. One common ingredient is chocolate, and who doesn’t love a good piece of chocolate? When thinking of chocolate, what comes to mind? The way it’s made, the way it tastes, the texture, or a favorite memory of a trip to the candy store?

Did you know that chocolate and metals are similar? At Applied Process one of the heat treatment cycles we do is a temper; a heating and cooling cycle to alter the properties of the iron or steel to the desired properties for our customer. Chocolate also gets tempered to achieve desired properties. Tempering is the process of melting and cooling chocolate so it will be smooth and glossy when it sets. A major difference between metallurgical tempering and chocolate tempering: metallurgically a temper is well below the melting point of the material – that’s the golden rule in the heat treatment business: Thou shalt not melt thy customer’s parts.

When you buy chocolate it means that it is already in temper – or that all of the fat crystals are aligned to give the chocolate perfect snap and shine. Untempered chocolate is often gray, streaky, and soft. Chocolate has different tempering temperatures based on fat content (dark, milk, or white) like metals have different tempering temperatures based on alloy content. Dark chocolate is the best for tempering because it’s more stable and easier to temper than milk or white chocolate. White chocolate has a lower melting temperature because it does not contain cocoa solids – it’s a mixture of cocoa butter, milk solids, and sugar and therefore can scorch easily. Milk chocolate melts at a lower temperature than dark chocolate, but higher than white. Milk chocolate will not achieve the snap that dark chocolate will.

Tempering metal isn’t the same as tempering chocolate – but there are some similarities. One is the quality of your material. Low quality chocolate will make low-quality candies just like you can’t fix a bad casting or forging with the best heat treatment. Heat treating affects the crystal structure of metals…and tempering chocolate realigns the fat crystals to give the desired snap and shine to the chocolate.

Whatever tradition it may be for you this holiday season, we hope you enjoy it!