Book SummarySalt, by Mark Kurlansky

1-Page Summary1-Page Book Summary of Salt

Salt is one of the cheapest, most commonplace items: It sells for less than a loaf of bread, and during winter, we scatter it liberally on roads and sidewalks. However, there was once a time when salt was considered rare and valuable. In Salt, Mark Kurlansky argues that throughout much of human history, salt was a precious commodity—one that significantly shaped civilizations. He traces the history of salt, describing the role it played in nourishing our ancestors, driving innovation, building empires—and even provoking rebellions.

Kurlansky, an American journalist, has published over 30 books on topics ranging from the history of cod to the history of nonviolent activism. While Salt is also a history book,...

Salt Summary What Is Salt?

When most people think of salt, they likely picture a sprinkling of white crystals and imagine a salty taste. However, according to Kurlansky, salt is more than this. He explains that salt is a term chemists use to describe a compound that’s produced when an acid reacts with a base. Kurlansky elaborates on the diversity of salts with the following facts:

Fact 1: Only some salt is edible. Some of the most common edible salts include table salt (sodium chloride) and baking soda (sodium bicarbonate). Inedible ones include barium chloride, a highly toxic salt used to make red pigments. (Shortform note: Some edible salts, such as table salt, are toxic if you eat them in extremely large quantities.)

Fact 2: Salt can taste salty, sour, or bitter. For instance, magnesium chloride...

Salt Summary Salt’s Biological Significance

According to Kurlansky, salt has played an important role throughout history because it’s necessary for humans’ and animals’ survival. Salt is crucial to cell function, brain and nervous system function, and digestion. Each of these bodily processes uses up salt, so we need to consume it to replenish our salt levels.

(Shortform note: Why is salt necessary for these bodily processes? When you eat salt, it separates into its two component ions, chloride and sodium. These ions dissolve in the fluid surrounding your cells and help conduct electricity that powers your cells. This electricity allows you to contract your muscles and transmit nerve impulses. Additionally, both of these ions play a crucial role in digestion: Chloride...

Salt Summary Salt’s Culinary Significance

In addition to enabling our survival, salt has culinary significance. Kurlansky argues that salt has played an important role in shaping cuisines around the world. First, salt preserves food, making it possible to eat when food production is low (such as during droughts). Second, salt is a seasoning that makes food more flavorful and palatable. In this section, we’ll further explore these two uses of salt.

Use 1: Preserving Food

According to Kurlansky, for most of history, salting was the primary method of preserving food. Only recently in modern history have we reduced our dependency on salt preservation, due to innovations such as refrigeration, freezing, and canning.

(Shortform note: While salt is no longer the primary way of preserving food, it’s still used as one of several preservatives in many shelf-stable foods. Studies reveal that when food manufacturers reduce the salt content of processed meat and cheese, it’s more likely those foods will carry bacteria responsible for botulism (a life-threatening illness that attacks your nervous system).)

Here, we’ll explore two main methods of preserving food with...

Salt Summary Salt’s Impact on Innovation

Because salt is necessary for life and eating, people throughout history have been motivated to develop ways to harvest it. Kurlansky argues that throughout history, salt has driven technological and scientific innovation. We’ll begin this section by exploring where salt is found on Earth so that we can better understand salt-harvesting innovations. Next, we’ll describe two of the main ways salt was harvested throughout history. Finally, we’ll examine how salt also played a role in other industries’ innovations.

Where Is Salt Found?

Kurlansky explains that salt is found:

• In water: Salt is found in oceans, springs, and some lakes.
• Underground: Underground salt deposits containing rock salt (salt in hard, mineral form) can span hundreds of miles. Some take the form of salt domes (mounds of salt that form when tectonic activity forces underground deposits upward).
• Above ground: Some mountains also contain large deposits of rock salt.

According to Kurlansky, for centuries, scientists have wondered and debated why the earth is so rich in salt. Today, there’s a general consensus that **salt deposits on land and underground got their salt from...

Salt Summary Salt Industries’ Impact on the Environment

Kurlansky argues that throughout history, salt industries and salt-related innovations have degraded the environment. Environmental damage in the English county of Cheshire, England’s leading salt producer for several centuries, exemplifies several of the ways salt industries can degrade the environment:

• Destruction of forests. Wood fueled Cheshire’s brine-boiling process of harvesting salt, and by the 17th century, salt harvesters had cleared most of the county’s forests.
• Air pollution. In the late 1800s, coal-burning furnaces fueled brine-boiling—and filled Cheshire’s skies with black plumes of soot.
• Sinkholes. Starting in the 18th century, sinkholes began wrecking homes and bridges in Cheshire. When harvesters pumped excessive brine from underground reserves, groundwater filled the gaps and dissolved the salt rock, causing sinkholes.

Salt Industries’ Impact on the Environment Today

Although today’s salt...

Salt Summary Salt’s Economic and Political Significance

Salt industries throughout history may have damaged the environment, but leaders of salt industries believed this damage was worth it—because salt production was extremely lucrative. Kurlansky argues that for most of human history, salt had both economic and political significance due to the profitability of the salt industry. In this section, we’ll explore how salt has shaped economies and politics for millennia. We’ve organized this section into three themes: the role salt played in 1) trade, 2) empire-building, and 3) rebellions and wars.

Theme 1: The Salt Trade Was Widespread

According to Kurlansky, salt was one of the first commodities traded over vast distances. For instance, around 2800 BCE, Egyptians exported salted fish to the Phoenicians, who occupied the North African coast. The Phonecians then traded Egyptian salted fish and North African salt with the rest of the Mediterranean.

(Shortform note: Other historical records reveal that the ancient Egyptians may have been engaged in long-distance trade of other goods even earlier than this. Artifacts from the fourth millennium BCE reveal that [pre-dynastic Egyptians traded with ancient...

Shortform Exercise: Review What You’ve Learned From Salt

Take some time to review the main takeaways from Salt.

The author claims that throughout history, salt has played a significant role in shaping cuisines, innovation, the environment, politics, and economies. Which of these impacts did you find most surprising? Why?