Abstract

Objective

Introduction

Did you know that butter is actually an ancient food? Records show that butter was being manufactured at least 2000 years before the birth of Christ! The earliest recipes for the manufacture of butter come from the Arabs and the Syrians. The original recipes call for the use of a vessel made from the skin of a goat. The skin was sewed together tightly, leaving only a small opening through which to add the cream. The vessel was then suspended from tent poles and swung until the butter formed. In the earliest centuries, butter was made and shipped from India. In the 12th century, the Scandinavians made butter and sent it to the rest of Europe. Nowadays, India consumes more butter than any other nation.

Butter is used in so many products, including cake batters and pastries, usually to produce a flaky or creamy texture and a delicious, rich flavor. But how can shaken cream simply turn into butter? Traditionally, when milk is allowed to sit for a while (up to a week), fat from the milk floats to the top. This fat is called cream. The cream is continually skimmed from the surface of the milk until no more is available. Cream is the source of butter. It takes about 21 pounds of fresh milk to make just 1 pound of butter! The cream must then be agitated (stirred up) so that the fat globules in the cream get shaken out of position. This causes the fat globules to clump together. The clumping first allows tiny air bubbles to be trapped in the cream, forming a light and airy product you might have had, called whipped cream. But if the agitation is continued, the fat globules start to clump so much that the air can no longer be held by the cream, the whipped cream seizes, and butter forms. This process is called churning.

A few years ago, we were told that butter was too high in fat and bad for your health. However, we now know that, in moderation, butter is an excellent source of vitamins and dietary cholesterol. So it turns out the ancient Greeks had it right—they thought butter had medicinal properties.

In this cooking and food science fair project, you will make your own butter. But is making butter a simple process? Does butter get formed by just shaking some cream around? You will see how temperature affects butter making and if using a souring agent, such as yogurt, helps or hinders.

Figure 1. A bowl of delicious homemade butter, ready to spread on your favorite treats!

Terms, Concepts, and Questions to Start Background Research

• Fat
• Churn
• Vitamin
• Cholesterol
• Souring agent
• Rancid

Questions

• What is fat?
• How do different cultures use butter in their cuisines and their traditions?
• What kinds of milk do people use to make butter?
• What is a vitamin?
• What makes some butter yellow and some butter more white?

Bibliography

The following website is a great one for all kinds of information about butter:

• Webexhibits. (n.d.). Butter Through the Ages. Retrieved March 10, 2009, from http://www.webexhibits.org/butter/index.html

This website has images that show the progression from cream to butter.

• Chu, M. (2005, June 3). Making Butter. Retrieved March 10, 2009, from http://www.cookingforengineers.com/article/113/Making-Butter
• Wikipedia Contributors. (2009, February 9). Butter. Wikipedia: The Free Encyclopedia. Retrieved March 10, 2009, from http://en.wikipedia.org/w/index.php?title=Butter&oldid=269509641

This science fair project is based on one found at the following website:

• Science Kids at Home. (2008). Making Butter. Retrieved March 10, 2009, from http://www.sciencekidsathome.com/science_experiments/making-butter.html

Materials and Equipment

• Glass canning jar with seals and rings, 1-quart (qt.), clean (1)
• Liquid measuring cup
• Heavy whipping cream (6 cups)
• Cups (6)
• Teaspoon
• Plain yogurt, small tub (1). The yogurt must have live and active cultures—check the ingredients label.
• Stopwatch
• Bowl
• Plastic baggies, sandwich-size
• Permanent marker
• Lab notebook
• Graph paper
• Optional: Digital camera

Experimental Procedure

1. Set out the clean jar and its lid.
2. Set out six cups. Using your liquid measuring cup, pour ½ cup of heavy whipping cream into each of the six cups and let them sit out at room temperature for 5 hours.
3. Now put 1 teaspoon (tsp.) of your souring agent, yogurt, into the empty and clean glass jar.
4. Into the jar with the yogurt, pour one of the ½ cups of the room-temperature cream.
5. Replace the lid on the jar.
6. Start shaking the jar. At the same time, start the stopwatch.
7. Shake the jar until butter forms. Initially, you will see and hear the cream slosh around. The cream will gradually thicken as the jar is shaken. Eventually, the cream will get so thick that it won't move much as you're shaking. Continue to shake the jar a little while longer, even if you don't hear any sloshing.
8. Once you have shaken the cream enough, the whey will separate from the butter. This change happens very suddenly. The butter will be a pale yellow color, while the whey will be a thin, milky liquid (that's basically how buttermilk is made). Stop the stopwatch when the whey and butter separate. Note down the time it took to form butter in a data table, like the one below, in your lab notebook.

Condition	Trial	Time Until Butter Forms (sec)	Observations
Room-temperature cream with 1 tsp. yogurt	1
	2
	3
Room-temperature cream without yogurt	1
	2
	3
Cold cream with 1 tsp. yogurt	1
	2
	3
Cold cream without yogurt	1
	2
	3

7. Carefully pour the whey out of the jar. Keep the whey in a cool spot for use in other recipes. Replace the lid and shake the jar for another 7 seconds to smooth out the butter and to remove any more whey.
8. Pour out any remaining whey and remove the lump of butter from the jar. Place it in a bowl of cold water. Wash your hands and gently knead the butter to remove any extra whey. Use your fingers to drain the liquid from the bowl and repeat this process a few more times. If all the whey is not removed, the butter will go rancid faster. Transfer the butter into a plastic baggie. Label the plastic baggie with the initial conditions of the cream (room temperature or refrigerated) and whether or not yogurt was used. Keep the butter in the refrigerator.
9. Clean the jar and the lid.
10. Now add one of the ½ cups of room temperature cream to the jar, but do not add any yogurt. Repeat steps 5–9. Record all data in your lab notebook.
11. Repeat steps 3–10, with the room-temperature cream, two more times. You should now have six batches of butter made from room-temperature cream. Three of the batches should have yogurt in the butter, and the other three should not have yogurt in the butter. Remember to always record your data in your lab notebook.
12. Repeat steps 3–11 three times, using cold cream straight from the refrigerator and a clean jar and lid. Do not bring the cream to room temperature. Record your data in your lab notebook.
13. If you would like, you can take a picture of each type of butter to include in your presentation.
14. Now that you have a complete set of data, it is time to analyze it. Graph the data on a scatter plot. If you would like to learn more about graphing, or would like to make your plots online, visit the following website: Create a Graph. Click on the XY button and then on scatter plot.
15. Label the x-axis Initial Conditions and the y-axis Shaking Time. Did temperature matter? What about whether or not yogurt was used? If there is a difference, what is the reason? How spread apart is the data for each initial condition?

Variations

• Compare the taste of your homemade butter to store-bought butter. Can you see and taste the difference?
• Weigh the amount of cream that you start with. Weigh the amount of butter that you end with. What percent of cream turned into butter?
• Ghee is a product that is made from butter and is also known as clarified butter. Make ghee from your butter. Explore how making ghee extends the shelf life and extends cooking temperatures.

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

Credits

Michelle Maranowski, PhD, Science Buddies

Last edit date: 2009-04-13 12:00:00