Homemade Butter

ButterBigger

Despite the misconception among certain pop culture icons that butter is a carb, butter, like other fats and oils, is a lipid. Broadly defined, lipids are any molecules that have hydrophobic, or water repelling, characteristics.  In contrast to simple molecules like water (H20) or sugar (C6H12O6), butter does not have one molecular formula; rather, it is a mixture of triglycerides. Here is what a triglyceride looks like [1]:

triglyceride

Triglycerides are molecules made of three fatty acids bound to glycerol, a sugar alcohol. Fatty acids are long hydrophobic chains of hydrogen and carbons that repel water. Triglycerides do not have to be the same three fatty acids, but can be mixed and matched. For example in butter, oleic acid (32%), myristic acid (20%), palmitic acid (15%) and searic acid (15%) make up the greatest percentage of the fatty acids [2].

buttercontent

In addition to all these lipids, surprisingly, butter contains water. While oil and water don’t normally mix, in butter, tiny microscopic water droplets are dispersed within the fat.  This is commonly known as a water-in-oil emulsion. An emulsion is any mixture of two liquids that don’t usually mix. The opposite of a water-in-oil emulsion would be an oil-in-water emulsion in which oil droplets are entrapped within water.

To understand the secret of how butter can be made of two immiscible liquids, we need to delve back into the molecular structure.  Butter is made from the cream, which has a higher fat content (15-25%) than milk (5 – 10%) [3].  In milk and cream, which are oil-in-water emulsions, the fatty triglycerides stay suspended in liquid because they are encapsulated in tiny fatty spheres or globules. Each globule is surrounded by a nanoscopically thin layer of phospolipids and stabilizing proteins. Phospholipds have hydrophobic lipid tails that love to repel water; they also have hydrophilic, or water loving, heads that contain a phosphate group (thus the name, phospho-lipid). Here is a picture of a phospholipid [1]:

phospholipid

The phospholipids organize themselves in a thin layer so that the water repelling hydrophobic portions are aligned with the fatty acid chains while the water loving hydrophilic heads interact with the milk liquid.  This allows the fats to remain dissolved in the milk and float around like little water balloons.

Milk Fat globule. (A) Diagram of the phosopholipid layer surrounding a fat globule [3]. (B) Cryo-electron microscopy image of a fat globule [4]. The scale bars are 0.1 μm.

Now, that we have talked about the structure of butter, how to get from cream to butter?  (Remember: milk and cream are oil-in-water emulsions and butter is a water-in-oil emulsion.) The oil-in-water emulsion of the cream is reversed into a water-in-oil emulsion in butter. During the churning or mixing process of butter making, the fatty globules in the cream break open to release the entrapped fat molecules. The hydrophobic fat molecules clump together and mix to form larger fat globules that coalesce into larger solid fat droplets. This processes pushes out the liquid portion and the solid portion becomes the butter.  Since these types of fat molecules typically melt at temperatures of 30 to 41°C (86 to 106°F), this means that at cool temperatures below approximately 39°F (4°C), the remaining liquid gets trapped within the solid fat matrix and is unable to separate out of the butter [5].

milktobutter

Below is a recipe for making your own homemade butter. You don’t need fancy equipment or churners like your ancestors used; a well-sealed glass jar works wonders.  The shear forces generated by rigorous shaking are sufficient to convert your cream into butter.

Ingredients

Heavy whipping cream (6 cups makes about 1lb of butter)
Salt, to taste
Jar with lid, any size

Procedure

1. Fill the jar about ¾ of the way to the top with the heavy whipping cream and close the lid.

2. Shake the jar for about 4-5 minutes until the cream begins to thicken. Shake longer if you wish for a thicker consistency.

The shaking motion breaks down the fat globules. The membranes surrounding each fat globule break, releasing the hydrophobic triglycerides. The triglycerides clump together and push away the hydrophilic liquid, the buttermilk.

3. Drain off the buttermilk and place butter in a small bowl. Knead the butter under cold running water to remove any remaining buttermilk.

4. Salt to taste. Form butter into a ball or log. Serve immediately or refrigerate.

Recipe Adapted From:

Online Resources

  1. General Chemistry Online: What is the chemical structure of butter?
  2. “Overview of the Buttermaking Process” from University of Guelph

References Cited

  1. K562. Overweight & obesity. http://www.indiana.edu/~k562/ob.html
  2. Fatty acids in butter. Percentage composition from Practical Physiological Chemistry, P. B. Hawk, O. Bergeim, Blakiston:Philadelphia, 1943.
  3. Gallier, S. et al. 2012. Structural changes of bovine milk fat globules during in vitro digestion. J Dairy Sci. 95(7): 3579- 3592.
  4. Robenek, H. et al 2006. Butyrophilin controls milk fat globule secretion. PNAS. 103 (27): 10385-10390.
  5. Butter: Some Technology and Chemistry. http://drinc.ucdavis.edu/dfoods1_new.htm

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

Read more by Vince Reyes


Butter Basics & Carl Sagan’s Apple Pie

CarlSaganPie

The New York Times discusses the proper care and handling of butter in baked goods, and Carl Sagan’s epic baking advice gets turned into an awesome recipe. Tastes like science! Read more

The Science of Pie: 2013 Event Recap

On Sunday we held our third and final 2013 Science and Food public lecture: The Science of Pie. Renowned pastry chef Christina Tosi joined us all the way from New York to explain her process for creating new desserts, and Los Angeles native and super-star baker Zoe Nathan shared her tips for baking the perfect apple pie. Guests indulged in delicious goodies from Zoe Nathan’s Huckleberry Café, Compost Cookies from Momofuku Milk Bar, and espresso brewed by four talented baristas.

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Zoe Nathan and Christina Tosi answer questions from the audience after their lectures.

And, of course, there was pie.

For weeks, students from the UCLA Science and Food course have been studying the apple pie and using scientific inquiry and experimentation to try to create the “ultimate” apple pie experience. Students examined everything from how different apple varieties behave in pie filling to how the size and shape of the pie affects baking. Several students also played with unconventional ingredients, including avocado oil, yogurt, chia seeds, and whiskey.

ScienceOfPieCooking

Students prepare their apple pies the morning of the event.

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Students share their research projects and apple pies with the public.

The students presented their research projects and pies at Sunday’s event. While the public enjoyed sampling the scientific treats, the pies were scrutinized by an esteemed panel of judges made up of chefs (Christina Tosi and Zoe Nathan), food critics (Evan Kleiman and Jonathan Gold), and scientists (UCLA Professors Andrea Kasko and Sally Krasne). After tasting the pies a talking with the students, the public voted for their favorite pie and the judges settled on three additional stand-outs. The lucky winners all took home wonderful prizes from our friends at Breville.

Best Overall Pie
Alia Welsh (Team Sablé)
Apple pie with shortbread crust and streusel topping.
This solo effort explored the vast parameter space of pie, studying the effect of fat content and temperature on the texture of the shortbread crust, as well as the effect of pH on the browning of the streusel topping. The final winning pie had shortbread made with room temperature standard American butter.

Best Tasting Pie
Stephan Phan, Kevin Yang, Amirari Diego (Team Apples to Apples)
Deconstructed apple pie with pie crust crumbs and spherified apples.
Using the technique of spherification, this team applied their knowledge of diffusion and gelation to prepare “reconstituted” apples. They found that optimizing both the calcium chloride concentration and gelation time was key to making a delicious modernist apple pie.

Judge’s Favorite Pie
Qiaoyi Wu, Qinqin Chen, Michelle Cheng (Team Aπ3)
Pie crust made with different liquids, including vodka, beer, and sparkling water.
Seeking to perfect pie crust texture, team Aπ3 experimented with different liquids that may impede the formation of gluten protein networks. Gluten gives structure and stability to pie dough, but can also make pie dough dense and tough when over-developed. The team examined the porousness, density, and browning of pie crusts prepared with three different liquids compared to water and concluded that vodka creates the flakiest pie crust.

People’s Choice Award
Elan Kramer, Caleb Turner (Team “Insert Team Name Here”)
Frozen apple pie with peanut butter mousse.
This student duo thought outside the box with this creative apple and peanut butter pie. To create the ultimate peanut butter experience, the team experimented with the effect of egg white content on the texture and density of the peanut butter mousse.

The Science of Pie was the perfect end to a fantastic lecture series. We are so grateful to our amazing lecturers and all the people and sponsors who made the lectures possible. And although the 2014 lectures might seem impossibly far away, don’t worry—the Science & Food blog is not going anywhere! Keep an eye on out for more exciting food science posts, profiles, recipes, and maybe even a few videos through the rest of the year.


Liz Roth-JohnsonAbout the author: Liz Roth-Johnson is a Ph.D. candidate in Molecular Biology at UCLA. If she’s not in the lab, you can usually find her experimenting in the kitchen.

Read more by Liz Roth-Johnson


Christina Tosi

Christina Tosi is the chef, owner, and founder of Momofuku Milk Bar, called “one of the most exciting bakeries in the country” by Bon Appetit Magazine. Her desire to explore new flavors and push creative boundaries has resulted in never-before-seen desserts including “Cereal Milk” soft serve, “Arnold Palmer” cake, and corn cookies. Christina lives in Brooklyn, New York with her three dogs and eats an unconscionable amount of raw cookie dough every day. Read more

Zoe Nathan

Zoe Nathan is the co-owner of several Los Angeles restaurants, including Huckleberry Bakery and Café and Milo and Olive. An avid baker, Zoe honed her craft at Tartine in San Francisco where she learned the value of using color as a flavor. At her own restaurants, she has received widespread acclaim for her pastries.

See Zoe Nathan speak at our next 2013 Science & Food public lecture!

The Science of Pie
Featuring Chefs Christina Tosi and Zoe Nathan
Sunday, May 19 @ 2:00pm
Covel Commons Grand Horizon Room (map)
BUY TICKETS

Image credit: Emily Hart Roth

Image credit: Emily Hart Roth

What hooked you on cooking?
I wanted to do something with my hands and was searching for a way to express myself in a way that I could connect with people around me instantly. I loved being able to make something and have someone eat it right away and hopefully enjoy it and understand where I’m coming from. Plus it just makes me really happy!
The coolest example of science in your food?
For me it’s the process of baking. Working with so few ingredients, and then deciding on different processes that will create totally different things to eat. That’s why I never worry about someone stealing a recipe from me, because at the end of the day, it’s not knowing what goes into baking something that makes it special, it’s how you bake it.
The food you find most fascinating?
Bread. For exactly the same reason as above. It’s all about process. That’s why I laugh when people say, “You can only make great Sourdough in San Francisco, or Bagels in New York,” but then I see people try with bad ingredients and a sloppy process. If you care enough you can make great bread anywhere.
One kitchen tool you could not live without?
Mixing bowls!
What scientific concept–food related or otherwise–do you find most fascinating?
The concept I find the most important in baking is the process of caramelization. You can use all the right ingredients and even the right process, but if you don’t get the right caramelization and color on a bake good it simply doesn’t look or taste good.
Five things most likely to be found in your fridge?
Eggs, kale, milk (I have a 2 year old), Dijon mustard, cream cheese.
Your best example of a food that is better because of science?
I’m not a big fan of modern science in cooking, but I’m super happy to have freezers so that I can freeze my scones and biscuits so that I can put the maximum amount of butter inside without having it leak out. I’m happy for convection ovens so my baked goods get that extra little jump. I’m happy for steam on my bread oven so my bread gets that nice shine. I’m also happy for bright lights so my bakers can come in at 3 a.m. and still feel safe!
Your all-time favorite ingredient? Favorite cookbook?
Salt is my all-time favorite ingredient. I have so many cookbooks that I love I can’t choose one.
How do you think science will impact your world of food in the next 5 years?
Honestly, I think it’s mostly negative. I think a lot of people eat processed foods because they’re easier to get because science has made them taste good and last a lot longer than it actually should. Because of all the big advancements in technology people are also used to getting what they want quickly, but good cooking is a patient thing, so I think fewer and fewer people know how to cook. I also think young cooks who are obsessed with immersion circulators and cvap machines often don’t know how to cook a piece of meat on a grill or in a pan which is a shame because that’s how it tastes best.
Your standard breakfast?
Leftovers from whatever my son hasn’t eaten and he eats pretty well. When I actually take the time to make it for myself it’s oatmeal cooked in homemade almond milk.

Celiac Vaccines & Whole-Grain Breads

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Scientists study a vaccine to cure celiac disease, while Mark Bittman shares his tips and tricks for making whole-grain breads at home. (Hint: you’ll want to get out your food processor!) Read more

Reinventing the Egg

Even if you’re not watching your cholesterol, there are plenty of reasons to avoid eating eggs. Ethical issues aside, industrial eggs provide only about 20% of the energy it takes to produce them. And while some egg substitutes do exist, they often pale in comparison to the real thing. Josh Tetrick, the CEO of Hampton Creek Foods, thinks we can do better. Read more