Scrumptious Science: Shaking for Butter
Have you ever wondered how butter is made? Butter is used in many tasty applications – hot pancakes with butter running down the sides, freshly baked biscuits and pastries with butter, and hot flaky potatoes with melted butter, to name just a few. Yum! While making butter can be hard work, it can also be easily made at home. In this activity you’ll not only get to find out how butter’s made, but also how temperature affects the butter-making process. And then you may enjoy the fruits (or rather, butter!) of your labors!
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
Butter is an ancient prepared food, having been made by people at least 4000 years ago. Some of the earliest known recipes call for the use of a vessel made from animal skin. The skin would be sewed together tightly, leaving a small opening through which to add fatty milk or cream. The vessel would then be suspended, such as from wooden poles, and swung until butter formed. For the last century, butter has been progressively produced in factories and is now used in many products, including cake batters and pastries, usually to produce a flaky or creamy texture and a delicious, rich flavor.
One traditional butter-making process begins with making cream. When milk sits out, tiny fat molecules float to the top of the milk, forming a layer of cream that can be skimmed and collected. To make butter from the cream, the cream is agitated (stirred up) so that the fat molecules get shaken out of position and clump together. Eventually, after enough agitation, the fat molecules clump so much that butter forms. When butter forms, the fat molecules have clearly separated from the liquid in the cream, and this liquid can be removed and made into buttermilk.
Extra: Repeat this activity a few more times. Do you get similar results each time you use cold heavy whipping cream or room-temperature cream, or is there variation in your results?
Extra: Weigh the amount of heavy whipping cream that you start with and then weigh the amount of butter that you end with. What percent of cream is turned into butter?
Extra: In this activity you investigated how temperature affects turning heavy whipping cream into butter but you did not quantify the temperatures you used. You could repeat this activity but this time use a thermometer to measure the temperature of the cream when you put it into the glass jar. You could even try some different temperatures of cream and see how that affects the process. How do different temperatures of cream affect the butter-making process?
Observations and Results
Did it take a much longer amount of time to make butter using the cold heavy whipping cream compared to using the room-temperature heavy whipping cream? Aside from this difference, did both butters seem similar?
As you shook each jar, you should have seen and heard the cream initially slosh around, and then gradually thickened. Eventually, after several seconds (but less than two minutes), it should have become so thick that it didn’t move much as you shook the jar. At this point the cream had likely turned into whipped cream. After you shook the jar for about 5 to 20 minutes total, the cream should have abruptly turned into butter. This likely happened much quicker for the room-temperature cream than for the cold cream. (For example, the room-temperature cream may have become butter after 5 to 6 minutes, whereas the cold cream took 13 to 15 minutes of shaking.) As the cream is shaken, the fat molecules get out of position and clump together, eventually clumping so much that butter forms. At this point the fat molecules have clearly separated from the liquid in the cream. When molecules are heated, they move faster because they have more energy. Consequently, the molecules in the room-temperature cream moved faster than the ones in the cold cream, allowing the room-temperature fat molecules to clump together faster and form butter faster.
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Teisha Rowland, PhD, Science Buddies
Science Buddies |
Chemistry, fat, heat
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