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Bloomin’ Chocolate

2609_imageAt my house Valentine’s Day means chocolate, the queen of all candy.  But have you ever opened a chocolate bar and found something that looks like this?

This whitish pattern on the surface of chocolate is called a bloom.  Blooms most often occur when chocolate is stored at a temperature that is too warm.  The fat begins to change form and push up through the chocolate causing this interesting pattern.

Occasionally you will see a similar effect caused by sugar.  You can tell the difference by touching the surface.  Fat blooms will be smooth and slightly greasy to the touch.  Sugar blooms will be dry and crumbly.  Rest assured that the chocolate is still safe to eat, although the texture may not be as smooth.  You can learn more about chocolate blooms at How Stuff Works.

If you want to grow your own blooms, simply take  some chocolate and melt it (either in the microwave or a warm, sunny window) until it just barely starts to melt.  Then put it in the fridge until it cools down again.  You will probably need to repeat this process several times before you see a result.

So how can you make a science fair project out of bloomin’ chocolate?  Here are a few questions to investigate:

  • Does the percentage of cocoa and/or sugar in chocolate affect how quickly chocolate blooms?
  • Choose just one type of chocolate and experiment to find the quickest method to causing a bloom.
  • Can you “unbloom” chocolate?  Try melting the chocolate all the way and then cooling it.
  • Is the bloom just on the surface or all the way through the bar?
  • Which type of chocolate blooms easiest; milk, dark or white?

Can you think of other questions to investigate?