Why Swiss Cheese Has Holes


As long-time readers know, on Fridays — like, you know, today — I do a week-in-review type of thing. Today, I want to talk about Monday’s bonus fact — a bonus fact that you haven’t seen yet because I screwed something up. As the title suggests, I’m going to talk about why swiss cheese has holes. And along the way, I’ll talk about the screw-up.

Monday’s story was about swiss cheese, and Agorscope, a Swiss government agency, created a way for cheesemakers to add special bacteria for the sole purpose of detecting counterfeit swiss. You can read that here, and you’ll see that there’s neither a bonus fact nor a featured article from my archives. What happened was simple: I wrote a bonus fact and chose that “from the archives” story, but then somehow copy/pasted over that work with the main story. So you got the main story twice, but no bonus fact or archive selection.

The archive selection was going to be “The History of Fondue and the Cheese Cartel that Popularized It,” which I wrote on May 20, 2015. The exact date of publication is important, so make a note of it. Here’s the bonus fact from that story:

The holes in Emmental cheese is caused by a gas emitted by a bacteria — gas which doesn’t escape during the cheese making process. Wikipedia explains: “In the late stage of cheese production, P. freudenreichii consumes the lactic acid excreted by the other bacteria, and releases carbon dioxide gas, which slowly forms the bubbles that make holes. Failure to remove CO2 bubbles during production, due to inconsistent pressing, results in the large holes (‘eyes’) characteristic of this cheese.”

When I wrote that back in 2015, I’m pretty sure I was right — or, rather, that’s what we collectively thought was the right answer at the time. In any event, I moved onto the next day and the next fact and story.  I didn’t go back to verify that the carbon dioxide theory was still true — why would I? But in writing Monday’s story about swiss cheese, I came across a new theory. This new theory became my (accidentally deleted) bonus fact for Monday’s newsletter. I’ll not bother to re-write it; instead, I’ll just share this article and the quote below from the BBC:

Scientists say they have discovered why Swiss cheese has holes in it: apparently, it is all down to how dirty buckets are when the milk is collected.

Contrary to what cartoons have suggested over the years, the holes are not made by mice eating their way through the cheese.

And nor are they produced by carbon dioxide released by bacteria, as popular scientific belief held.

Instead, a Swiss laboratory says they are created by flecks of hay.

Agroscope, a government agricultural institute, said “microscopically small hay particles” would fall in to buckets collecting milk, and develop into bigger holes as the cheese matures.

That BBC article was published on May 28, 2015 — about a week after I wrote my original article about fondue. And the agency that did the study, Agroscope, was the same agency that came up with the bacteria I spoke about in Monday’s newsletter.

I really like it when things like that come together, even if it means the fact “changed” a week or so after I initially wrote about it. And because I screwed up the copy/paste, I have added reason to talk about it today. So out of two mistakes of a sort comes another fun story. I’ll take that as a win.

The Now I Know Week in Review

Monday: The Secret of the Swiss Cheese: See above! 

Tuesday: The Problem With Jam: This has nothing to do with grape jelly or strawberry preserves, or anything else that goes well with toast.

Wednesday: The Balloon Shields: How balloons kept bombs away.

Thursday: The Den of Unanimity: Going into the lion’s den — literally — to make sure everyone gets to vote.

And some other things you should check out:

Some long reads for the weekend.

1) “Day of Rage: An In-Depth Look at How a Mob Stormed the Capitol” (New York Times, 40-minute video, June 2021). I’ve gone back and forth about whether to share this one. The reason against: it is, by definition, very political. But that’s the only reason. First, it is exceptionally well done, taking dozens of sources of video footage and editing them to tell one story. Second, it’s about an important topic. And finally, and most importantly for me, I actually learned a lot of new things from it. That surprised me — I’ve been following the developments and investigations into the insurrection closely, and yet, this wasn’t just review.  Rep. Adam Kinzinger calls it “a must-watch video” and he’s right: it is.

2) “Unknown Knowns” (Issues Magazine, 8 minutes, Fall 2020). Former U.S. Secretary of Defense Donald Rumsfeld passed away earlier this week, causing this article to pop onto my radar. Rumsfeld once noted that “there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say, we know there are some things we do not know. But there are also unknown unknowns—the ones we don’t know we don’t know.” He was mostly ridiculed for this, but I have to admit, I’ve always found it to be a very useful framework. 

This article, though, goes one further. It notes that it misses a category: unknown knowns. Basically, there is a category of things we know, but we either choose to recognize that we know it or we subconsciously block out that knowledge. This is a look into why we do that, and how we can avoid fooling ourselves.

3) “The Internet Is Rotting” (The Atlantic, 26 minutes, July 2021). Websites go offline, newsletters disappear into the trash, etc. What happens to all of the stuff online that can’t be found? Is that knowledge lost forever? Here’s a look into a problem that digital was supposed to solve.

Have a great weekend!