How To Teach Science… With Candy (Part 3)
Let’s review a couple of things before we dive into another way to change the texture of candy. First of all, you learned the following rule in Part I of How To Teach Science With Candy:
THE MORE WATER A SYRUP CONTAINS, THE SOFTER THE CANDY WILL BE
This rule has to do with the TEMPERATURE of the heated sugar water solution. The higher the temperature of syrup, the less water it will have as it boils off and DIFFUSES into the atmosphere.
In Part II of How To Teach Science With Candy, you learned about another rule in candy making:
HOT SYRUPS FORM ROUGH, JAGGED CRYSTALS AND COOLER SYRUPS FORM SMOOTH, SMALLER CRYSTALS
This means that hot syrups contain many ATOMS that have absorbed a lot of energy and are bouncing around inside the solution. All of this bouncing keeps sugar molecules from binding together very easily into crystals. (How easy would it be for you to hold on to someone if an army of people kept slamming into you?) However, the few crystals that DO happen to form grow very quickly as ATOMS continue to bind to their surface.
So the big question is – How do we make smooth textured candies?
Before we tackle that question, let’s review the four main concepts of science:
IT’S TIME TO STIR THINGS UP!
You just read that “cooler syrups form smooth, smaller crystals.” Therefore, all you need to do is make certain that the syrup you have cooked is cooled down considerably before you start…
STIRRING!
As a syrup solution cools, its ATOMS are DIFFUSING their energy into the bowl and the environment in the form of heat. As this energy leaves the ATOMS, they slow down to the point where they are not bouncing into each other anymore. When this happens they cannot bind to the crystals that exist within the syrup. However, you can force sugar molecules together by STIRRING the solution!
In fact, you create a massive amount of sugar crystals as you stir the cooled syrup. This means the DENSITY of sugar crystals increases as long as you keep stirring the solution! This is very good if you want a smooth candy with lots of tiny crystals!
Remember… larger crystals are formed in hot syrups as many of the newly created tiny crystals are broken apart by fast moving sugar molecules.
Not only are there slower moving sugar molecules in a cool syrup, there is another cool trick to making smooth candies with lots of tiny crystals:
As more and more sugar crystals are formed within the cool syrup, there are fewer sugar molecules floating around in the syrup. With fewer free sugar molecules moving around, the existing crystals will be unable to grow very large!
This is the secret to having bulging arm muscles when making fudge. In order to get the smooth texture of this delicious dessert, you need to mix the cooled syrup very hard for a very long time! Because if you stop stirring, you stop making smaller crystals! This means the existing crystals in the syrup immediately begin to grow very large! This will make the texture of your fudge gritty and coarse.
It may SOUND like it’s no big deal, but you’ll be sweating before you’re done! It take a lot of stirring to make fudge!
Okay… quick review:
Hot syrup = fewer, large crystals
Cool syrup = more, smaller crystals
Making crystals = no destruction or creation of any atoms (Don’t’ forget the LAW OF CONSERVATION!)
Learn more about chemistry concepts (and many more) in the Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!
