Key concepts
Food science
Have you ever cooked up homemade candy? Maybe from chocolate—or table sugar? Maple syrup is not only deliciously gooey and great on breakfast foods such as pancakes and waffles, it can also amazingly turn into maple candies with a range of textures. For example, it can be made into sticky maple taffy or hard, molded maple sugar candy. Early spring is the time of year when maple producers in North America start to tap their trees and collect the sap to turn it into maple syrup, so it's a perfect time to explore this tasty, fascinating food. In this science activity, you will investigate how the temperature of heated-up maple syrup affects what types of candies can be made from it.
Chemically speaking, maple syrup is a concentrated solution of sugar in water, with many minor flavoring compounds. It is made by collecting sap from certain maple trees and boiling it. The sap contains a lot of sugar, primarily in the form of sucrose, although there are also small amounts of glucose and fructose. The sap is gently boiled until it is the right consistency—not too watery (or the maple syrup could easily spoil) and not too thick (or the sugar in the maple syrup could harden and crystalize).
How does boiling the sap change its consistency? When a sugary solution is heated, some of the water evaporates, and this makes the sugar more concentrated in the solution and the overall product thicker. As the heated maple syrup cools, sugar molecules (the smallest particles of the sugar) can form crystals. The amount of crystals that form depends on how concentrated the sugar is.
This same principle is used to turn maple syrup into different types of sugary candies. To make maple candies, maple syrup is heated more, and this makes the sugar in the candies even more concentrated than it is in the maple syrup!

  • Baking pan or hard candy molds
  • Cooking oil if using candy molds. If you are using a baking pan, you can use wax paper instead of cooking oil.
  • Half a cup of pure maple syrup (make sure it is not imitation syrup!)
  • Stove (use adult assistance when using the stove and handling hot objects)
  • Saucepan
  • Large spoon for stirring
  • Candy thermometer or digital thermometer that can withstand temperatures of at least 310 degrees Fahrenheit or 154 degrees Celsius
  • A metal measuring teaspoon
  • Place your baking pan or hard candy molds on the counter next to the stove.
  • If you are using a baking pan, cover it with a sheet of wax paper or lightly grease it with cooking oil. If you are using hard candy molds, lightly grease the molds with cooking oil.
  • Make sure an adult helps and supervises while using the stove and heating the maple syrup. Also be sure to only use a metal measuring teaspoon, because the heated maple syrup can melt plastics!
  • Heat half a cup of maple syrup over medium heat in the saucepan, uncovered, using a large spoon to stir it occasionally at first. Use a thermometer to carefully measure the temperature of the maple syrup as you begin to heat it up. How quickly does the temperature of the maple syrup increase?
  • Bring the maple syrup to a boil and allow it to cook, uncovered, while you stir frequently to make sure it does not burn. Carefully use the thermometer to measure the temperature of the maple syrup as you continue to heat it. How quickly does the temperature increase now?
  • When the temperature of the maple syrup reaches 230 to 235 degrees Fahrenheit, carefully use a metal measuring teaspoon to take an approximately one-teaspoon sample of the heated maple syrup. Quickly pour the teaspoon of heated maple syrup onto the baking pan or candy mold. Do not touch the candies until they have cooled! How easy is it to scoop and pour the heated maple syrup? What is its consistency like?
  • Similarly take four more samples as the maple syrup heats, specifically one sample each at 245 to 250 degrees Fahrenheit, 255 to 260 degrees Fahrenheit, 270 to 280 degrees Fahrenheit and 300 to 310 degrees Fahrenheit. Keep track of which candy came from which temperature sample. How easy is it to scoop and pour each of the different samples? How are they similar and different from each other? What do you notice about the maple syrup in the saucepan as the syrup is heated up?
  • When you have made your five samples, let them all cool to room temperature and then investigate them. What is the color of each sample? Is it transparent? Does it feel sticky, smooth and/or rough? Does it seem caramelized? Is it flexible, or does it break when bent?
  • When you are done making your visual observations, try tasting—or having a volunteer taste—each sample. How does each one taste? Which is the sweetest? Which has the best texture? Which one do you like the most overall?
  • Overall, how does it seem that heating the maple syrup affects the type of candy it can turn into? How are these candies similar to, and different from, maple syrup–based candies that you can buy?
  • Extra: You could try this activity again, but this time make several samples (at least three) at each temperature you test, and invite friends and family for taste testing. Which samples do other people prefer? Is it always the same, or do some people prefer different aspects?
  • Extra: Maple syrup is mostly made of the sugar sucrose and water. There are many different types of sugars, and you could design a way to make solutions of these other sugars and similarly test them. Do they make candies similar to the ones made with heated maple syrup?
  • Extra: Repeat this activity using imitation maple syrup instead of real, pure maple syrup. Does imitation maple syrup make candies the same way that pure maple syrup does? If it makes different candies, how are they different?
  • Extra: Another way to make different candy samples is by doing the "cold water candy test" (check out the "More to explore" section for a link and details). Try making maple candy samples using maple syrup heated to different stages according to this test. How do the candy samples compare to each other? How are they similar to, or different from, the candy samples made in the first activity?

Observations and results
Did the hottest temperatures make the darkest, stiffest, sweetest candies, while the lowest temperatures made honey-colored, transparent, sticky candies?
Just as maple syrup is made by boiling and concentrating sap from trees, maple syrup–based candies are made by heating up maple syrup to concentrate it further. The hotter and longer the syrup is heated, the more concentrated the sugar (and other ingredients) in it becomes as the water evaporates away. This is why you should have seen that the candies made from maple syrup that was heated the longest (to around 270 to 310 degrees Fahrenheit) was the darkest (a light or dark brown color), non-transparent, rough in texture, stiff when you tried to bend them (breaking cleanly), but quite sweet! Meanwhile, the candies made from maple syrup that was not heated as long (to around 230 to 250 degrees Fahrenheit) should have been the most like maple syrup—they should have been honey-colored, transparent, sticky but smooth in appearance, and very flexible, but not super sweet.
When you think about your results, you compare about the difference between the texture of caramels and lollipops—the caramel is softer and chewier, while the lollipop is hard and cracks when it is bitten. The syrup used to make caramels is cooked until it reaches 240 to 250 degrees Fahrenheit, at which point is has an 87 percent concentration of sugar and enters the "firm-ball stage." The syrup used to make lollipops, however, is cooked until it has a 99 percent concentration of sugar (at a temperature of 300 to 310 degrees Fahrenheit), which makes drops of the syrup turn into hard, brittle, easy-to-break threads when placed in cold water.
To clean the saucepan, spoons, stove or other kitchen items that may have gotten hot maple syrup on them, soak them with hot, soapy water and then scrub the remaining maple syrup off.
More to explore
The cold water candy test, from Exploratorium
Making Maple Syrup Candy: How Does Temperature Affect It?, from Science Buddies
Maple Candy and Other Confections (pdf), from The Ohio State University Extension
Science Activities for All Ages!, from Science Buddies

This activity brought to you in partnership with Science Buddies