Ryerson prof shares chocolate secrets

If that beautiful box of premium chocolates you received for Valentine’s or Easter has been stored in the refrigerator, don’t be surprised if the sweets develop a hazy tinge.

“When chocolate is subjected to variable temperatures its exterior gets chalky and it no longer looks appetizing,” says Derick Rousseau, a food science professor at Toronto’s Ryerson University.

He says the condition is known as fat bloom and occurs for a number of reasons, but often results when chocolate is exposed to temperature fluctuations.

When the temperature of the chocolate goes up and down, some of the cocoa butter in the chocolate melts and resolidifies. A small amount of this resolidified cocoa butter will end up on the surface as microscopic crystals or bumps. This produces the hazy whiteness called fat bloom, Rousseau explains.

“As consumers of chocolate we say, ‘gosh, the sheen has gone and it looks kind of chalky and not very appetizing.”

“But it hasn’t gone mouldy, and you can eat it. The texture might not be exactly the same, but it is still fine to eat.”

Rousseau says another drawback in storing chocolate can happen when it is exposed to damp and wet conditions. This is called sugar bloom.

“If chocolate is exposed to humid conditions, moisture in the air will condense the surface of the chocolate and dissolve the sugar. When conditions become dry again, the sugar will re-crystallize and the surface will look hazy.”

Rousseau’s work examines the microscopic appearance (the microstructure) of chocolate and the physical and chemical factors that negatively affect its quality and shelf life. His research is aimed at helping to keep chocolate fresher and tastier.

Here are some of his tips on storing chocolate:

• If stored properly, chocolate can last for years. Filled chocolates and truffles are best consumed within a month.
• To preserve the flavour of chocolate, it must be kept in a cool, dry, well-ventilated place where there is little variation in temperature and low humidity.
• To avoid fluctuations in temperature, do not store chocolate in cupboards right next to your fridge or stove.
• Chocolate should be stored in an airtight container.
• Because chocolate contains fat, it easily absorbs other flavours and odours. Don’t store near chemicals, cleaning products, perfume, air fresheners or anything else you don’t want to taste in your chocolate.

– The Canadian Press