The Tasty Rock that Changed the World

Salt: A World History

Today’s Nat’s Notes is all about Salt! The tasty rock that changed the world.

I was recommended Salt: A World History by multiple people because the impact salt has had on the world is so much bigger than you think.

They were right to recommend it.

I was blown away by these stories about how salt has changed the world, and got really excited as I was reading to share them with you.

I love books like this that make you see such a simple thing, salt, in a completely new way.

Whether you read these highlights or listen to the episode, I guarantee you’re going to learn something that makes you look at salt in a completely new light.

I also did something a little different today. Instead of summarizing the episode in this newsletter, I pulled out 22 cool facts about salt I learned while reading.

As always, if you want to listen to the full podcast, subscribe to the Nat’s Notes podcast on YouTube, Spotify, Apple, Amazon, or anywhere else you listen to podcasts by searching “Nat’s Notes.”

This edition is sponsored by Readwise!

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Readwise is your knowledge hub for everything you read. It can automatically import your highlights from Kindle, Instapaper, Pocket, and even scan your highlights from physical books.

Then anytime you want to reference your favorite parts of a book, you can immediately search them on Readwise, or in any note-taking app you connect your Readwise to like Notion.

They also recently launched the Readwise Reader which is what I use for reading all articles now, since it has a fantastic built-in highlighting tool that makes it easy to see anything you loved from past articles you read.

This is honestly the best tool out there for getting more out of everything you read. And they’re offering readers of Nat’s Notes a 2 month free trial to check it out. Just go to to get started.

1: You die if you don’t get enough salt, but there’s no reflex for salt deficiency the way we experience thirst or hunger.

That might be why we evolved to find salt so tasty. It was a form of self-preservation.

2: Agricultural society couldn’t exist without a source for salt.

Hunter-gatherer societies got enough salt from the red meat in their diet, but once we transitioned to agriculture, we needed to supplement with salt to survive.

Farming, cities, modern life as we know it couldn’t exist without established, reliable sources of salt, which is why it became such a valuable and impactful commodity.

3: Salted and pickled food has been found as old as 5,000 years, and we probably knew how to do it long before then.

4: Until canning and refrigeration were developed, salt was the only reliable way to preserve meat and vegetables for long periods of time, so you needed salt if you didn’t want your food to immediately spoil.

This was especially important since once we transitioned to agriculture, we had more irregular harvests. You couldn’t eat all of your crops before they spoiled, so we needed salt to preserve them for when we needed them.

5: Salt breaks down the proteins in meat similar to cooking, and actually makes it easier for us to digest.

That’s why it’s much easier to eat prosciutto than raw pork.

6: We’ve been concerned about salt’s impact on blood pressure for 2,000 years.

An ancient Chinese medicinal guide called “The Yellow Emperor's Classic of Internal Medicine” says that too much salt can cause high blood pressure and strokes.

7: Salt was so essential to society that it ended up getting embedded in many fertility rites and associated with fertility.

“Celibate Egyptian priests abstained from salt because it excited sexual desire; in Borneo, when Dayak tribesmen returned from taking heads, the abstinence from both sex and salt was required; when a Pima killed an Apache, both he and his wife abstained from sex and salt for three weeks.”

8: The locations of early cities were not just based on access to water, but also access to salt.

There’s a major salt deposit in upstate New York that Buffalo used to travel to for their salt, and when we established a city there we named it Buffalo New York.

9: Early trade routes were often optimized around salt.

Rome’s first major road was called the Via Salaria the “Salt Road,” because it was used to transport salt to Rome’s military.

“By the Middle Ages, caravans of 40.000 camels carried salt from Taoudenni to Timbuktu, a 435-mile journey taking as long as one month.”

10: Salt was at times a form of money.

Roman soldiers were sometimes paid in salt, which is where the word “salary” comes from, and the term “worth his salt.”

The latin word for salt “sal,” became the French word for pay “solde,” which is the origin of the word soldier

11: Salt was a very common form of tax for governments to enrich themselves, which when overdone often led to revolt.

The revolutions in America, France, and India, were all partially motivated by unfair salt taxes.

Rome and China both levied aggressive salt taxes on their populations at various times to pay for wars and enrich the government.

12: Venice’s original wealth was built on monopolizing the salt trade in the Mediterranean.

They were one of the first societies to figure out they could make more money manipulating the salt market instead of harvesting it themselves.

For 200 years they controlled trade in the Mediterranean thanks to their aggressive monopolization of the flow of salt, and using their salt trade to subsidize other goods.

13: Sweden once bought an island in the Caribbean to get access to more salt so they could sell more salted fish from their bountiful northern waters.

Unfortunately, because of the weight of salt, transporting it back was too expensive for them to profit off the purchase.

14: Some of the most formidable navies were salt cartels, like the merchant ships from Venice and the Hanseatic league ships.

These salt cartels would often go to war with states like England, Denmark, and Spain, and win because they were such powerful navies.

15: Fish and salt cartels were brutal, almost like modern drug cartels.

The Hanseatic league which controlled the flow of fish and salt in Northern Europe during the 1200s to 1500s would regularly tie up people and throw them into the ocean if they caught them fishing in their waters.

16: When Cortez landed in the Americas, part of how he conquered the local population was by taking control of their salt works.

He knew the importance of controlling the salt trade from seeing its effects in Europe, and used it to dominate the indigenous civilizations.

17: The main product of the Carribbean in the early colonial days was not sugar, or rum, but salt.

It was one of the best early places in the new world for building saltworks to supply the colonies, because ocean water would get trapped in various bays and lakes on the islands and could be easily evaporated to harvest salt.

18: One of the first salt works established in the American colonies was on Coney Island

It was an ideal location to supply New Amsterdam, eventually New York, with salt.

19: Prior to the French Revolution, the French salt tax was so disproportionate across different regions that you would pay 20x more for salt in some cities than others.

This led to highly profitable salt smuggling, and “something close to a state of permanent warfare developed between the salt smugglers and the [salt tax collectors].”

20: Going into the American Civil War, the south only produced 1/6 as much salt as the North.

This ended up becoming a huge strategic disadvantage, especially as Lincoln sent ships to destroy Southern saltworks along the coast, especially in Florida.

Within three years of the war starting, salt prices in the South increased by 50x.

21: Drilling for salt water is how we discovered natural gas, and started cooking and heating with gas 2,000 years ago.

This was also how the first drills were developed, and the same kind of drilling technology was used for salt water and natural gas wells for over a thousand years.

22: Salt also helped us find oil wells.

Salt traps organic matter causing it to decompose into oil over time, so we have often found significant oil reserves in places that we already knew had salt licks.

Some of the huge oil reserves in Iran were found in the same places Herodotus wrote about having salt 2,500 years ago.


Thank you so much for reading.

If you learned something, please forward this to a friend.

I’ll return next week with another fascinating book to share.