Jason Crawford

Early in Pasteur's career, when he was still more of a chemist than a microbiologist, because microbiology barely existed at that point,

Pasteur was asked to help the wine, beer, and vinegar makers of France.

Something that seems almost comically utilitarian when you look back at what an amazing scientist this guy was.

But Pasteur didn't think of this work as beneath him.

And he went out and he helped these folks with their fermentation processes.

They were having trouble.

They weren't getting consistent results.

Sometimes the wine or the vinegar or whatever would turn out bad.

They didn't know why.

So Pasteur goes and he's exploring what is going on with this fermentation, what causes the different outcomes.

And he realizes something that had been hypothesized or had been put forth by others but that had not been conclusively demonstrated and had not been accepted generally, which is that microbes in the wine, beer, et cetera, were actually driving the fermentation process.

The scientific establishment at the time did not want to believe this.

It smacked of vitalism.

But Pasteur, through diligent and careful experiments, showed that the microbes, the yeast and bacteria and so forth that we found in these substances were not just incidental, nor were they simply feeding off of the fermentation, but they were actually driving it.

And in fact, through this, he discovered that part of what was going on was that fermentation was driven by anaerobic metabolism in these microbes, that when they were cut off from oxygen, when they could not use oxygen, they switched to metabolizing sugars and turning it into alcohol and carbon dioxide.

So I just think this is amazing, right?

Pasteur goes into this like very utilitarian, just kind of like process optimization within industries, not even industries, but like crafts, you know, that had been around for thousands of years.

And along the way in, you know, just trying to make wine and beer better, he discovers these fundamental principles of microbiology.

So it's interesting to me how he was able to sort of pivot from a very utilitarian practical concern to a very scientific theoretical concern.

But he also pivoted in the other direction as well, perhaps even more dramatically.