finding the right ratio of sugar to corn syrup

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Difficulty 5 – 6

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Mixing Your Own Marshmallows: Finding the Right Ratio ofSugar to Corn Syrup

Abstract

Whether you’re sitting around a campfire, or drinking hot chocolate after a day in the snow, nothing says fun quite like amarshmallow! Even its name is soft and spongy! In this cooking and food science fair project, you’ll make your ownmarshmallows several different ways, and discover the three special ingredients that give marshmallows their uniquetexture. You’ll also find out why they melt so quickly. Explore the science of these sticky, spongy sweets!

Objective

To determine the ratio of sugar to corn syrup that produces the best-tasting and best-textured marshmallow.

Introduction

What’s your favorite way to eat a marshmallow? Melted in hot chocolate after a long day of sledding? Or roasted andsquished between a slab of chocolate and graham crackers while you’re sitting around a campfire? However you like them,marshmallows are an unusual type of sweet treat—spongy, sticky, and a little bit chewy, with a melting point that is just abit above body temperature, so that they start to change from a solid to more liquid state as soon as they reach the warmthof your mouth, or the warmth of your hot chocolate or campfire! They are also an ancient creation, originally coming from atall marshmallow plant that grows in swampy fields and has a soft, spongy root. The root contains mucilage, a thick, glueysubstance produced by some plants and microscopic animals to help with water and food storage, and seed germination.Some cultures used the marshmallow plant to make candy, while others used it to make medicine. The ancient Egyptians,for example, dried the root and mixed it with honey to make marshmallow treats, but the early French thought the rootlooked like lung tissue, and experimented with making medicine out of its gummy juice to soothe sore throats.

Today’s modern marshmallows contain no parts of the marshmallow plant though, because the plant is considered amedicinal herb. Instead, modern marshmallows are primarily a mix of three ingredients: sugar, corn syrup, and gelatin, withthe gelatin replacing the thick, gluey substance from the marshmallow plant. The sugar and corn syrup are heated togetherwith a little water to make a solution. The solution is warmed and brought to a boil, turning it into syrup. Because of thesugar in the solution, the boiling point of the solution becomes higher than the boiling point of pure liquid water (212°F).The greater the concentration of sugar in a solution, the higher its boiling point. As the solution boils, water evaporates,and the solution becomes even more concentrated with sugar, and the boiling point gets pushed even higher. For example,an 85 percent sugar solution has a boiling point about 28°F higher than the boiling point of pure water.

The final concentration of sugar in the syrup determines the structure of the candy that forms when the syrup cools. Thinkabout the difference between the texture of caramels and lollipops—the caramel is softer and chewier, while the lollipop ishard and cracks when it is bitten. The syrup used to make caramels is cooked until it reaches 240–250°F, at which point ithas an 87 percent concentration of sugar in solution and enters the firm ball stage (see the Exploratorium link in theBibliography for more information about this). The syrup used to make lollipops, though, is cooked until it reaches a 99percent concentration of sugar in solution (at a temperature of 300–310°F), which makes drops of the syrup turn into hard,brittle, easy-to-break threads when placed in cold water. When making marshmallows, the syrup is cooked until it reaches235–240°F, or 85 percent concentration of sugar in solution, and corn syrup is added to the solution to help prevent crystalsfrom forming in the cooled syrup. Nobody likes crunchy marshmallows!

So, where does the gelatin come in, and just what is gelatin anyway? Gelatin is that wiggly, jiggly food that seems almost magical as it suspends fruits, forms shapesand sculptures, and transforms from a solid to a liquid as soon as it hits the warmth of your mouth. It’s not magic, but special gelatin molecules are responsible forthese food tricks. Gelatin comes from collagen, the main protein in connective tissue, which is a specialized, fibrous tissue in animals that connects other tissuestogether, like tendons connect muscles to bone. The special quality of gelatin is that it is a protein that can coagulate (or come together) when it is beaten or whipped.So, to make marshmallows, hot concentrated syrup is beaten into gelatin with a mixer. The beating process forms bubbles in the syrup and protein mixture, and thegelatin coagulates at the point where the air in the bubble and the syrup-protein mixture meet, stabilizing the bubble walls so they don’t collapse.

In this cooking and food science fair project, you’ll make your own gooey marshmallows, using different amounts of sugar and corn syrup to find out which ratio ofsugar to corn syrup, makes the best-tasting and best-textured treat.

Terms, Concepts and Questions to Start Background Research

Figure 1. This photo shows a yummy marshmallow treat (called a s’more). (LarryD. Moore, 2006.)

Mixing Your Own Marshmallows: Finding the Right Ratio of S... http://www.sciencebuddies.org/science-fair-projects/project_ide...

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Solution

Boiling point

Concentration

Protein

Coagulate

Ratio

Force

Questions

From where did ancient marshmallows come, and how were they used?

What are the main ingredients in modern marshmallows?

What happens to the boiling point of a solution as the concentration increases?

Why is corn syrup added to marshmallows today?

Why is gelatin important in making marshmallows?

Bibliography

Exploratorium. (n.d.). Science of Candy: Monster Mallows. Retrieved December 16, 2009, from http://www.exploratorium.edu/cooking/candy/activity-mallows.html

Exploratorium. (n.d.). The Cold Water Candy Test. Retrieved January 21, 2010, from http://www.exploratorium.edu/cooking/candy/sugar-stages.html#softcrack

Cooking for Engineers. (2009, December 19). Marshmallows by Michael Chu. Retrieved December 18, 2009, from http://www.cookingforengineers.com/recipe/106/Marshmallows

Materials and Equipment

Square foil cake pan, 8 or 9"; round foil pie pans are a possible substitute (9)

Masking tape

Vegetable oil, like canola or safflower oil, for greasing pans

Paper towels (1 roll)

Powdered or confectioners sugar (3 cups)

Strainer, small

Large mixing bowl

Gelatin, plain, unflavored; available at grocery stores (1 box)

Fork

Small saucepan with lid

Measuring spoons

Corn syrup, like light corn syrup; glucose syrup is a possible substitute (32 fl. oz)

Granulated sugar (10 cups)

Pure vanilla extract (5 tsp.)

Dry measuring cups

Candy thermometer

Lab notebook

Electric mixer or beater

Timer

Pizza wheel

Spatula

Ruler

Large air-tight containers, or gallon-size sealable plastic bags (3)

Additional materials may be needed, depending on tests you choose to run on your marshmallows. See Testing Your Marshmallows, below, for more details.

Graph paper

Experimental Procedure

Preparing to Cook

Wash your hands.1.

Get out all cooking tools and ingredients, and set them out so they are ready to go and easy to access.2.

Identify the 240°F mark on your candy thermometer. This is the traditional temperature used to make marshmallows.3.

Preparing Your Cake Pans

Label the bottoms of three cake pan with masking tape pieces, numbered from 1 to 3. Pan 1 will contain recipe 1, pan 2 will contain recipe 2, and pan 3 willcontain recipe 3. Each recipe contains a different ratio of sugar to corn syrup.

1.

Pour a small amount of vegetable oil on a paper towel and lightly oil the three cake pans.2.

Pour a small amount of powdered (confectioner’s) sugar in the strainer and dust the inside of the cake pans.3.

If you get too much powdered sugar in the pan, hold the pan upside-down over a sink, and gently tap out the excess.a.


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Preparing Your Gelatin

Pour 1/6 cup of cold water into the large mixing bowl1.

To get 1/6 cup, just fill up the 1/3 measuring cup up halfway with water.a.

Sprinkle one packet of plain, unflavored gelatin over the cold water.2.

Mix the gelatin and water together for about 5 seconds (sec.) with a fork and set the bowl aside. This will give the gelatin time to "soften" or "bloom."3.

Figure 2. This photo shows the gelatin "blooming" in a small amount of water.

Preparing Your Syrup

Add ¼ cup of cold water to the saucepan.1.

Using the table below as a guide, add granulated sugar and corn syrup to the water in the saucepan, according to which recipe you are currently making.2.

Recipe Table

Ingredients Recipe 1 Recipe 2 Recipe 3

Sugar 1/2 cup 2/3 cup 3/4 cup

Corn syrup 1/3 cup 1/4 cup 1/6 cup

Ratio of sugar to corn syrup 1/2:1/3 2/3:1/4 3/4:1/6

Ratio, written as a decimal 1.5 2.7 4.5


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Figure 3. This photo shows the small saucepan containing water, sugar, and corn syrup, ready to be warmed on the stove to form a syrup.

Put the lid on the saucepan. An adult should closely supervise all work from this point on.3.

Turn on the stove to medium-high heat.4.

Lift the lid and check the solution in the saucepan about every 30 sec. until it just comes to a boil.5.

Remove the lid and set it aside.6.

Begin to measure the temperature of the syrup in the saucepan using the candy thermometer.7.

When using the thermometer, do not let the tip of the thermometer touch the bottom or sides of the pan. Instead, try to put the tip below the surface,closer to the middle of the pan.

a.

Continue heating your syrup solution until the temperature reaches 240°F.8.

WARNING: The syrup will be very hot, so use extreme caution when working around the pan.a.

Observe how the temperature rises. Does it go up quickly at first? What happens as the solution becomes more concentrated? Record your observations inyour lab notebook.

b.

When the temperature reaches 240°F, immediately turn off the stove and move to the next section, Making Your Marshmallows.9.

Making Your Marshmallows

Turn the mixer on low, and slowly pour the hot syrup solution into the gelatin and water in the large mixing bowl.1.

Figure 4. This photo shows the hot syrup slowly being poured into the gelatin while the mixer isoperating on low.


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Turn on the timer.2.

Gradually increase the speed of the mixer until it is operating at full (high) speed.3.

Figure 5. This photo shows how the mixture will look as you begin to operate the mixer athigh speed.

Continue to beat for approximately 11 minutes, or until the mixture starts to become very thick, glossy, and lukewarm.4.

Add ½ teaspoon of vanilla, and beat for another minute.5.

Write down the total time that you beat the recipe in your lab notebook.a.

Try to beat each recipe for approximately the same amount of time.b.

Figure 6. This photo gives an example of how the mixture will look at the end of 11minutes after you have added the vanilla, and before you beat for the final minute.

Pour a thin layer of vegetable oil on a spatula and scoop out the marshmallow mixture from the mixing bowl and into the prepared cake pan with the maskingtape piece that matches the recipe number.

6.

Use the spatula to gently smooth down the top of the marshmallow, so that it is pretty flat.7.


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Wash and dry all cooking utensils, and then repeat the entire Experimental Procedure two more times with clean materials, until all three recipes have beenprepared, so that you have a total of three trials for each recipe. Repeating the recipe makes sure that your test results are accurate and repeatable.

8.

You may want to do this step on a different day.a.

Figure 7. This photo shows the three finished recipes cooling and becoming more firm.

Allow the three marshmallow "pies" to sit out, uncovered, on a counter for at least 4 hours, or up to overnight, so that they can become firm.9.

Preparing Your Marshmallows for Testing

Once the marshmallow pies have become firm, after at least 4 hours or overnight, turn the pans over, one at a time, onto a cutting board.1.

If the marshmallow sticks to the bottom of the pan, push on the bottom of the pan a bit, or use a spatula to help lift it out.a.

Roll a pizza cutter in some powdered sugar, and then use it to cut up your marshmallow into ½-inch or 1-inch pieces, whatever you prefer. Use a ruler to helpmeasure where to cut.

2.

An alternative to the pizza wheel is to use a cookie cutter to cut out shapes.a.

Dust the marshmallows on all sides with a little powdered sugar, using the strainer.3.

Place the marshmallows in the air-tight container or plastic bag, being sure to label the container or bag with the trial number (remember, you will be performingthree trials) and the recipe number from the masking tape pieces, so that you know which recipe was used for each bag or container. The marshmallows will keepin an airtight container for up to a week, so you have around six days in which to make and test all the trials.

4.

Testing Your Marshmallows

There are many ways you can test your marshmallows. Perform each test one trial set at a time. You could do:

Melting tests: Drop three marshmallows (one from each recipe) in a pan of hot water. Because of slight variations in marshmallow sizes, you should try to pickthree that are of the same size and shape. Start a timer and see which one melts first, second, and last. Repeat the test at least three times per trial set to makesure your results are repeatable and accurate.

1.

Cutting tests: See which marshmallow is the toughest using a cheese cutter and coins, like the test described in the Science Buddies cooking and food science fairproject Tough Beans.

2.

Taste tests: Gather your family and friends and give them three samples of marshmallows, one from each recipe in a trial set. Have them evaluate the samplesfor taste and texture. Which one do they prefer? Read this Science Buddies article about sample size to determine how many volunteers you will need.

3.

Analyzing Your Results

For melting tests, average the results of your time tests from the three trials, and plot the decimal ratio of sugar to corn syrup on the x-axis, and the melting timeon the y-axis.

1.

For cutting tests, average your coin counts from the three trials (to get a measure of the force required to cut through the marshmallow), and plot the decimalratio of sugar to corn syrup on the x-axis, and coin counts (or cutting force) on the y-axis.

2.

For taste tests, make a bar chart showing the ratio of sugar to corn syrup on the x-axis, and the number of people who thought it had the best taste on they-axis. Make a second bar chart showing the decimal ratio of sugar to corn syrup on the x-axis, and the number of people who thought it had the best texture onthe y-axis.

3.

Variations

Develop other ways to test your marshmallows. For example, measure the density of the marshmallows from each recipe, using a scale, graduated cylinder, andArchimedes’ principle. Plot the ratio of the sugar to corn syrup on the x-axis and the density on the y-axis.

Choose the recipe that has a decimal ratio of 2.7 for the sugar to corn syrup. Vary the final cooking temperature (deviate from the traditional 240°F) to see howthat affects the taste, texture, melting time, toughness, and/or density. Be sure to conduct repeat trials at each temperature you test.

Break up your taste-testing volunteers into male and female, or by age, to see if there are gender or age differences in marshmallow taste or texture preferences.

For more science project ideas in this area of science, see Cooking & Food Science Project Ideas.

Credits

Kristin Strong, Science Buddies

Last edit date: 2010-03-01 12:00:00

Career Focus


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Food Science TechnicianGood taste, texture, quality, and safety are all veryimportant in the food industry. Food sciencetechnicians test and catalog the physical and chemicalproperties of food to help ensure these aspects.

BiochemistGrowing, aging, digesting—all of these are examples ofchemical processes performed by living organisms.Biochemists study how these types of chemical actionshappen in cells and tissues, and monitor what effectsnew substances, like food additives and medicines,have on living organisms.

Food Scientist or TechnologistThere is a fraction of the world's population thatdoesn't have enough to eat or doesn't have access tofood that is nutritionally rich. Food scientists ortechnologists work to find new sources of food thathave the right nutrition levels and that are safe forhuman consumption. In fact, our nation's food supplydepends on food scientists and technologists that testand develop foods that meet and exceed governmentfood safety standards. If you are interested incombining biology, chemistry, and the knowledge thatyou are helping people, then a career as a foodscientist or technologist could be a great choice foryou!

If you like this project, you might enjoy exploring careers in Cooking & Food Science.

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finding the right ratio of sugar to corn syrup

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