Long before modern refrigeration, the ancient Inca Empire was preserving food for years and moving it across vast distances. Archaeologists have now uncovered rare evidence of that system in Peru. 

The unearthed freeze-dried potatoes. Image credits: L. M. Valdez in Valdez and Bettcher 2026

Two freeze-dried potatoes, called chuño (an ancient potato snack), dated to the 15th or 16th century, were found by archaeologists inside a storage room at the Inca site of Tambo Viejo.

The discovery reported in a recent study is remarkable not simply because the potatoes survived for roughly 500 years, but because they were found far from the only places where they could have been made. 

According to the researchers, the freeze-dried potatoes were originally made in the freezing highlands of the Andes before being transported to the coast. Their presence at Tambo Viejo amounts to evidence of the food-storage and distribution network that helped sustain the Inca Empire across a vast territory.

A broken storage jar preserved a 500-year-old meal

Archaeologists have known from historical accounts that freeze-dried potatoes played a central role in feeding the Inca Empire. Warehouses stocked with preserved food are thought to have supported soldiers, workers, and communities during shortages.

“Early colonial period documents inform us that the freeze-dried potatoes were safely stored for extended periods of time in state-controlled warehouses,” the study authors note.

Yet physical archaeological evidence has been extremely scarce. This is because potatoes are about 80 percent water and usually decay quickly after harvest. As a result, researchers have had written descriptions of chuño production, but very few surviving examples. 

Before the new discovery, only one comparable archaeological find had been reported from the Inca world.

The current discovery was made during excavations at Tambo Viejo, an Inca provincial center in Peru’s Acarí Valley. During the 2024 field season, researchers uncovered a small storage room containing a clay vessel buried in the floor. 

Although the upper half of the container was missing, the soil inside had protected its contents for centuries. As archaeologists removed the sediment, they found two shriveled potato-like objects resting near the bottom of the vessel. 

The researchers immediately recognized them as chuño, which is still made in parts of the Andes today.  It is believed that the potatoes’ survival was helped by the extremely dry conditions of the Acarí Valley. 

The arid environment slows the decay of organic materials that would normally decompose. The same conditions have preserved other ancient remains at Tambo Viejo, allowing the freeze-dried potatoes to survive for centuries.

Moreover, the potatoes were found alongside an Inca pottery fragment and a broken spindle whorl, a tool used for spinning fibers into thread. These associated artifacts helped confirm that the storage room belonged to the Inca occupation of the site during the 15th or 16th century.

What the potatoes reveal about the Inca Empire

Chuño is created through a simple but effective preservation process. Potatoes are repeatedly exposed to freezing nighttime temperatures and strong daytime sunlight. Over multiple cycles, moisture is removed from the potatoes, creating a lightweight product that can remain edible for years without refrigeration.

However, the freeze-drying process requires regular hard frosts and therefore can only be carried out at elevations above roughly 3,600 meters (11,800 feet) in the Andes. 

Tambo Viejo, however, sits on Peru’s warmer coastal plain, where such conditions do not exist. This means the potatoes must have been produced in the highlands and transported to the coast. 

This is clear and direct evidence that the Inca Empire operated a large-scale food distribution system that linked distant regions. Since chuño could remain edible after long periods in storage, it was an ideal food reserve. 

Such preserved supplies helped the Inca administration support laborers, military campaigns, and large construction projects while reducing the risk of food shortages.

“Given that potatoes spoil quickly, chuño production was a savvy strategy not only to prevent the loss of important food but also to create large volumes of food reserves that were used to support imperial projects,” the study authors added.

Researchers believe llama caravans carried the chuño along the Inca road network, moving food across hundreds of kilometers. Since freeze-drying removes most of the water, the potatoes would have been much lighter and easier to transport than fresh crops.

Ancient lessons for modern food security

Beyond revealing how the Inca Empire moved food across vast distances, the discovery also highlights the value of preservation techniques developed centuries ago. 

According to the researchers, chuño production was a practical strategy that reduced food loss and created reserves that could be stored for long periods and used when needed.

This ancient solution to food preservation may hold lessons for a world grappling with food waste and food security today.

“We still have so much to learn from the people of the past. Food security is a main concern, even in our times; yet we waste food, perhaps more than at any time in human history,” Lidio Valdez, lead researcher and an archaeologist at the University of Calgary, told Live Science.

Relatively few Inca sites along Peru’s coast have been systematically excavated, raising the possibility that additional examples of chuño and other preserved foods could emerge in future investigations. 

The study is published in the Journal of Field Archaeology.