Mad about Science: Peanut butter

By Brenden Bobby
Reader Staff

Peanut butter and jelly sandwiches are an American staple, but have you ever stopped to ask yourself why? What is it about solid nuts transformed into a non-Newtonian fluid that speaks to simpler times?

The answer to that is actually pretty straightforward: one of the greatest and most destructive economic downturns of all time.

Peanut butter is a spreadable paste made from blended peanuts and hydrogenated oils. In many cases, sugar and trans fats are added to the mixture to make the taste more appealing, though at the expense of our waistlines.

You may associate the invention of peanut butter to George Washington Carver, but it already existed for at least two centuries in some form before he published How to Grow the Peanut and 105 Ways of Preparing It for Human Consumption in 1916.

There is evidence to suggest that peanut butter originated in the Inca Empire — likely sometime in the 16th century, prior to the Spanish invasion — where it was used as a remedy for aching gums. This seems to be backed up by modern nutritional sciences, as peanut butter is a soft food that’s high in protein and vitamin E, which helps provide antioxidants to cells while boosting your immune system.

Before you eat an entire jar of peanut butter to help shake off the common cold, be aware of the adverse effects of consuming large amounts of sugars and trans fats. These are both core causes of obesity, and by extension the development of type 2 diabetes. As is the case with most nutrition, moderation is the key to living a healthy life.

Two tablespoons is considered one serving of peanut butter. The sugar content varies by brand, with natural peanut butter having about one gram of sugar per serving, while more processed products can have up to four grams per serving. This isn’t a huge amount, but it does add up if you eat a lot of it.

As a non-Newtonian fluid, peanut butter has interesting properties shared with other condiments such as ketchup and mayonnaise. It stays in one place and doesn’t flow easily until force is applied. This is considered a Bingham plastic — a non-Newtonian fluid whose other examples include mud and toothpaste. Interestingly, the TSA classifies peanut butter as a liquid, since it will mold to fit the shape of the container in which it’s transported, even when it behaves as a solid until pressure is applied.

Despite claiming all the fame surrounding peanut butter, George Washington Carver wasn’t actually involved with inventing peanut butter at all. Three other men were credited with the invention of modern peanut butter after patenting mechanisms for creating the sweet treat.

Marcellus Gilmore Edson was the first to patent the process in 1884, which involved rolling roasted peanuts between two heated surfaces. John Harvey Kellogg, founder of Kellogg’s cereal company.

(Bonus fact: Kellogg, Idaho, is not named after the cereal tycoon, but instead named after Noah Kellogg, a mining prospector. This makes a lot of sense when you consider that Kellogg is a mining town and not a cereal town.)

In 1895, Kellogg patented the process for creating peanut butter from raw peanuts rather than roasted ones. Despite his fame, modern peanut butter production is largely done by first roasting the peanuts.

In 1903, Ambrose Straub patented a machine that would grind peanuts to make peanut butter. It’s likely that this is the origin of the peanut butter machines you find in the bulk food sections of grocery stores like Yoke’s Fresh Market.

Peanut butter hit its cultural stride during the Great Depression, when it became a cheap and easy source of protein for starving families. Much like Kraft American cheese, it grew to prominence during WWII and remained a cultural mainstay during the postwar period once the G.I.s returned home.

Modern industrial peanut butter manufacturing begins with roasting the peanuts. Controlling the cooking process is essential, so the moment the peanuts reach a desired temperature — transforming from their natural white to the beige-brown we recognize — they’re directed under cooling jets that blast them with cool air. This keeps them from cooking too much and losing their oil.

A blancher removes the skins of the peanut by rolling them between two rubber belts. Each peanut is then split and its bitter core is removed. These two components are repurposed for animal feed. 

At this point, the peanuts are dropped into the grinder and mixed with other ingredients: sugar, salt and hydrogenated oil. Now it looks like a recognizable peanut butter as it is heated and cooled one more time, then extruded into jars to be sealed and packaged for distribution. 

It’s a relatively uncomplicated process, but the machines involved are quite complex to produce such a simple product. Making peanut butter at home requires only an oven, a blender, peanuts, some salt and oil. You can even add sweeteners or seasonings to your peanut butter to mix up the taste. If you’re making crunchy peanut butter, set aside some chopped-up peanuts and mix them in at the end of the process.

Many nuts can be converted into nut butter of some kind, though peanut butter is one of the easiest and tastiest to make.

Stay curious, 7B.