Summary
Introduction
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 like pancakes and waffles—you can also turn it into maple candies with an amazing range of textures! It can be made into sticky maple taffy, or hard, molded maple sugar candy. In this science activity, you will investigate how the temperature of heated maple syrup affects what types of candies can be made from it.
Materials
- 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 cup of pure maple syrup (make sure it is not artificial maple 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° Fahrenheit or 154° Celsius
- A metal measuring teaspoon
Prep Work
- 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 heating the maple syrup on the stove. Also be sure to only use a metal measuring teaspoon, because heated maple syrup can melt plastic!
Instructions
- Heat half a cup of maple syrup over medium heat in the saucepan, uncovered, using a large spoon to stir it occasionally. 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. Now, you must stir it 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. Covering the tip of the thermometer with the hot syrup is enough to measure the temperature.
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 approximate 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, one 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?
- Look back at all your data.
Overall, how does it seem that heating the maple syrup affects the type of candy it can turn into? If you have tried store-bought maple syrup-based candies before, how are these candies similar and different?
Cleanup
What Happened?
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 sap from trees to reduce its water content, maple syrup-based candies are made by heating up maple syrup to reduce the water content further. The hotter and longer the syrup is heated, the more concentrated the sugar (and other ingredients) in it becomes as the water evaporates. 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, rougher 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.
Digging Deeper
Chemically speaking, maple syrup is a concentrated solution of sugar in water, with many minor flavoring compounds.
A solution is a mixture where one substance is dissolved into another. A solution is always homogeneous, or the same throughout. Maple syrup is a concentrated solution as it has a lot of sugar compared to the amount of water. It is made by collecting sap from certain maple trees and boiling it. The sap contains 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 further, and this makes the sugar in the candies even more concentrated than it is in the maple syrup!
When you think about your results, you can compare the texture of a caramel and a lollipop—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 it 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.
Ask an Expert
For Further Exploration
- 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?
- 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?
- 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?
Related Resources
Project Ideas
Activities
Links
- Blog Post: Candy Color Chromatography
- Blog Post: Kitchen Science Roundup!
