This summer, I had the pleasure of having coffee in Palo Alto with Eva. She had been to the Exploratorium the day before, where, in the gift shop, she picked up a couple cool science books for the sprogs. “Of course, you’ll have to blog them!” she said.

Of course!

Today, we look at one of those books.

Louis Pasteur and Pasteurization

Written by Jennifer Fandel

Illustrated by Keith Wilson, Rodney Ramos, and Charles Barnett III

This book isn’t a biography of Louis Pasteur. Instead, it’s a discussion of what he discovered and (more importantly, from the point of view of the Free-Ride offspring) how he discovered it.

We start with a glimpse of life in the mid-1800s, when the guy who milks the cow coughs into his hands and then sets about the task of milking without stopping to wash those hands.

Hands which the sprogs would call “germy” but which people at the time would not, since no one knew that germs caused disease.

The elder Free-Ride offspring was actually a little surprised that in those times scientists had already seen germs through microscopes. It’s just that no one knew what those microorganisms did. (People also weren’t clear on where microorganisms came from, but we’ll get to that in a moment.) And, knowing that germs existed wasn’t really enough to keep people (especially non-scientists) from spreading them, which meant that your morning milk could be a good source of calcium and tuberculosis.

When Pasteur enters the story, he’s not focused on milk but on wine. He was asked to solve the mystery of why some batches of wine went bad. A peek under the microscope showed the good wine to be populated by yeast and the bad wine to have some yeasts and a lot of rod-shaped microorganisms. The winemaker was happy to have a way to tell good wine from bad before selling it, but Pasteur wanted to know more.

It turns out that people in the mid-1800s thought that yeast was a product of wine fermentation rather than an ingredient required to make things ferment. Pasteur sets up a nice experiment with water, sugar, yeast, and nitrogen in sealed flasks to see which of these ingredients was necessary for fermentation. (He used four flasks; you can probably figure out how he had to set them up to answer the question.)

After he learned all kinds of nice things about yeast, he figured out that those rod-shaped microorganisms in the bad wine were the same ones that can be found in spoiled milk. (As it happens, we are using the same kind of lactic acid producing bacteria right now to pickle slices of daikon radishes.)

The next challenge was figuring out how to get rid of the unwanted microorganisms.

The book goes on to describe Pasteur’s experiments in developing a process (Pasteurization) that would kill the bad bacteria without spoiling the taste of the wine. It also discusses the experiments Pasteur performed to demonstrate that microorganisms are not the product of spontaneous generation, but are kicking around in the air we breathe (and into which we sneeze).

The elder Free-Ride offspring was taken by the fact that, after Pasteur’s discoveries, city dairies started offering a service where you could bring in your raw milk to get it pasteurized. Another surprise was that these experiments were not originally driven by an effort to stop the spread of disease, but to an effort not to sell bad wine.

I pondered whether these experiments would ever have been done in the first place if microorganisms didn’t make things taste different. Some of the microorganisms featured in the story — like the germ that causes tuberculosis — apparently didn’t make the milk taste any different at all.

This isn’t really a little-kid book, but the comic book style of presentation will grab middle-grades grade school kid. The discussions of Pasteur’s methodological experiments are especially nice.

Finally, the younger Free-Ride would like to contribute a related joke:

A princess told her maid that she wanted to take a bath in milk.

The maid asked, “Would you like it pasteurized?”

The princess answered, “No, up to my shoulders will be fine.”