A Brief Introduction to Food Preservation Techniques

Find out how ancient humans were able to preserve meat and ensure adequate salt intake by curing meats.

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Clearly, one significant challenge to early humans was how to manage quantities of meat, poultry, fish, and other perishables beyond what people could eat immediately during one or two meals. The development of methods to preserve meat and foods such as grains, milk, and other perishables helped steer humans on our evolutionary path. Sometimes our contemporary fascination and desire for the latest unique food or flavor overlooks how a long history of necessity and struggle for survival are the foundations of extraordinary tastes and unique cultural expressions. The practice of salting and dry curing was an essential preservation technique to manage fresh meat resources and to survive harsh winter months. These preserved foods served as a pantry when food was scarce. Our forebears preserved a remarkably diverse array of great-tasting foods using different combinations of techniques.

Because food preservation was critical to human survival, air- and sun-drying most likely preceded salt and dry curing, all dependent upon favorable geography and climate. In Asian, Egyptian, and Middle Eastern deserts, air- and sun-drying methods sufficed; strips of meat would dry quickly in these arid, hot environments. Archaeological evidence from early cave dwellings in Africa and the Middle East reveals soot deposits on ceilings and walls from fires used to keep people warm, cook food, and provide protection. Prehistoric humans hung meats from the ceiling to dry and smoke.

The Quechua, Aymara, and Inca peoples, living in South America’s Andes Mountains and taking advantage of the high-altitude cold and dry atmosphere, utilized freeze-drying methods to preserve potatoes centuries before high-tech machinery created foods for long-distance hikers. Variations of jerky, derived from the Quechua word ch’arki, meaning dried, salted meat, were found throughout the Americas. In similar fashion Inuit and other arctic dwellers preserved wild salmon by hanging butterflied fish in cold, dry winds. Some two thousand to three thousand years ago in North America, Native peoples cut strips of bison, venison, elk, llama, and moose meat to air- and sun-dry. Many tribes pulverized the jerky and added fat, dried berries, and flavorings to produce pemmican, a lightweight, energy- and protein-dense food. They later taught these techniques to Europeans. Robert Peary took pemmican on his expeditions to the North Pole, while Roald Amundsen and Ernest Shackleton carried it to the South Pole.

Although definitive evidence does not exist for dates of its initial discovery, humans, whether nomadic or sedentary, later developed salt curing as a technique to preserve what they gathered and hunted or their first harvests. A fundamental necessity for early salt-curing practices was access to the mineral resource, and therefore, the technique appeared in different places around the world. These sources included evaporated ocean water, prehistoric deposits, saline pools, and myriad other sites. Since humans and other mammals require salt to live, our ancestors knew where to find adequate supplies. At certain times and places, eating meat was as much about salt requirements as the other physical needs for proteins, fats, and other nutrients.

The word “cure” stems from the Latin word curare, “to take care of.” Beyond a method to preserve food, cure relates to healing or restoring health, a medical remedy, or the means to correct something troublesome or detrimental. The linguistic intersection of food and medicine expresses clearly that ancient peoples both understood and nurtured a close physical relationship between what they ate and human health.

Most important for our focus on dry-cured meat, by 3000 BCE China and Middle Eastern civilizations used salt curing for a variety of foodstuffs. The practice of preserving meat with salt appears to have originated in Asian deserts:

Saline salts from this area contained impurities such as nitrates that contributed to the characteristic red colour of cured meats. As early as 3000 BC in Mesopotamia, cooked meats and fish were preserved in sesame oil and dried salted meat and fish were part of the Sumerian diet. Salt from the Dead Sea was in use by Jewish inhabitants around 1600 BC, and by 1200 BC, the Phoenicians were trading salted fish in the Eastern Mediterranean region. By 900 BC, salt was being produced in “salt gardens” in Greece and dry salt curing and smoking of meat were well established. The Romans (200 BC) acquired curing procedures from the Greeks and further developed methods to “pickle” various kinds of meats in a brine marinade.

On a trip to China in 1986, as our party passed through rural villages, I saw whole dried corn cobs, cascades of chiles resembling Mexican ristras, and bundles of odd-looking mahogany-colored pods, all hanging under roof eaves to dry in the sun. The dark red-brown pods were lawei, a southern China cured-meat specialty that resembles Native American jerky. During the lunar calendar’s twelfth month, the ancient Chinese made numerous gifts to their gods, including large quantities of sacrificial animals, poultry, and fish. To preserve the leftovers, the populace, especially in southern provinces with short winters, created lawei. The cured meat took many forms: pork (làròu), sausage (làcháng), even chicken (làji?) and fish (làyú). “Historical records show that more than 2,000 years ago, Confucius charged every student some làròu as a tuition fee,” a reflection of its culinary value and financial worth. For làròu, làji?, and làyú, the meat was cut in strips, marinated in salt and spices, and then hung to dry. In “Guangdong, Sichuan and Hunan, smoking the meat is an indispensable final step to infuse it with an appetizing color and fragrance. Làcháng, the fatty sausages often used in southern cooking, are prepared in a slightly different way – seasoned sliced pork is stuffed into a pig’s small intestines and hung to dry.”

Early humans made sausages from cleaned, cooked intestines stuffed into stomachs. The use of intestines and stomachs reflected a need to utilize the entire animal. The stomach was large enough to accommodate other ingredients, such as grains, spices, and other offal. Haggis, Scotland’s national dish, is a combination of ground sheep offal, oats, fat, spices, and other items stuffed into the animal’s stomach and boiled. The organ’s resiliency and strength made it possible to thoroughly cook the pudding.

In ancient Rome, while the elite ate the best cuts of pork, the poor enjoyed different types of fresh and smoked sausages; in Latin, botulus (or botellus, for a small sausage). Named after its origin in the southern region Lucania (today’s Basilicata), Lucanian sausage is one of the earliest documented botuli. De re coquinaria (“On the Subject of Cooking”), a late fourth- or early fifth-century CE compilation of Roman recipes, describes one for Lucanian sausage that contained pounded pork spiced with pepper, cumin, savory, rue, parsley, bayberries, garum (a Roman fish sauce), fat, and pine nuts. After being thoroughly mixed, the concoction was forced into intestines and smoked.

From the Romans to the present, we find recipes very similar to Lucanian sausage, from French boudin to blood sausage, mortadella to frankfurters. The technique of finely pounding, mincing, or emulsifying meats into sometimes nearly liquid compositions, combined with other ingredients, created savory dishes – the original pudding – that solidified when stuffed by medieval European cooks into different-size casings and then boiled or steamed. Linguists suggest the term “pudding” came from the French “boudin,” whose origin in turn was the Latin “botellus.”

The process of dry-curing sausage differs from that for hams, but each must achieve a similar end point of safety. If preservation techniques are not applied, sausage and ham spoil, and if done improperly, these meats are potentially dangerous. Whether we consider whole muscles such as ham or the chopped, ground, minced, or otherwise cut-up meat of sausage, all must be treated with salt to cure, killing off bacteria and other harmful micro- organisms. Through osmosis, salt draws water from bacteria cells, drying them out until rendered harmless. Dry-cured sausage (in contrast to fresh sausages like boudin and Lucanian sausage) was mixed with salt and often saltpeter (potassium nitrate), both of which kill microbes such as bacteria.

In addition to the word “pudding,” another noteworthy bit of Roman historical and linguistic lineage relates to ham-curing practices. The word “prosciutto” comes from the verb prosciugare, which in Italian means “to dry from the inside out.” Prosciugare is a combination of the Latin pro (before) and exsuctus (past participle of exsugere) “to suck out [the moisture].” Hence, it means to dry up, all dried up, or lacking juice. The exact historical sequence of ham curing in Europe remains hidden. We know that 2,200-year-old Greek curing techniques guided later Roman practices, while the Larousse Gastronomique argues that Gaul was the origin of cured ham somewhere between 200 and 100 BCE. Whether true or not, cured hams were certainly known and consumed by Romans. Roman aristocracy enjoyed both cooked hams (prosciutto cotto) and cured hams(prosciutto crudo [raw]), certainly as early as 160 BCE, if not earlier.

Roman senator Marcus Cato the Elder described how to salt hams in De agri cultura (“On Farming”) ca. 160 BCE. The techniques he described are still the basic recipe used today to make both prosciutto di Parma and prosciutto di San Daniele. For centuries regional ham producers worked with the four seasons, each approximately three-month period providing critical temperature and humidity differences to stimulate salt penetration and enzymatic transformation deep in the muscles. Farmers or a norcino, a traveling butcher, would slaughter hogs in November or December, and the process to cure the hams began. Except for the hog’s exposed exterior and skin, the ham muscles are sterile unless diseased or damaged in some way.

To preserve the whole muscle, therefore, requires specific salting techniques; after trimming, the exposed flesh is covered with dry salt, while the skin receives a wet salt. After salt was applied, the hams were hung in caves, where cold temperatures and wind helped retard spoilage, as the salt began its penetration into the meat. Hams would be washed and sometimes re-salted, and hung to dry for about three months. Prior to the last aging phase, a producer coated each ham with sugna, a mix of spread- able fat, salt, pepper, and occasionally rice flour, to protect them from excessive drying and hungry insects. During the final step the hams hung in a cool cellar, and as temperatures and humidity changed, the magical alchemy occurred as the ham slowly dried. Depending on the size of the ham and variations in weather, it could age for twelve or more months. Although techniques to produce Parma and San Daniele prosciutto differ, both regions reflect a fundamental reliance on climate and geography. The unique characteristics of wind, temperature, humidity, and geology (at least before the twentieth-century introduction of refrigeration removed a key variable from the production of both regional hams) contribute to distinctive differences in terroir.


This excerpt is from Jeffrey P. Robert’s book Salted and Cured: Savoring the Culture, Heritage, and Flavor of America’s Preserved Meats (Chelsea Green Publishing, April 2017) and is reprinted with permission from the publisher.

 Jeffrey P. Roberts is president of Cow Creek Creative Ventures, which is dedicated to developing solutions in the areas of agriculture and food policy, conservation, the environment, and community economic development. He is the author of The Atlas of American Artisan Cheese (Chelsea Green, 2007) and Salted and Cured (Chelsea Green, 2017). He teaches the history and culture of food at the New England Culinary Institute, is a visiting professor at the University of Gastronomic Science, provides consulting services to a wide array of small-scale food producers, and is a frequent speaker in Europe and the United States on artisan food, sustainable agriculture, and the working landscape.

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