If you’re like me, the last post on the convoluted origins of our favorite fermented condiment—ketchup—probably left you wondering: What is the difference between Roman garum than modern Thai fish sauce?
What little I know comes from an experiment performed by Sally Grainger, author of Cooking Apicus, recounted in the book Cured, Fermented and Smoked Foods. Grainger is a British chef and an experimental archeologist. She looked at studies on fish sauce amphorae (ceramic vessels) from archeological sites in Spain and North Africa. One of her more fascinating sources comes from a 2,000-year-old shipwreck discovered off the coast of Grado, Italy. The ship was full of fish—maybe even live ones. Italian researchers found that the vessel contained what amounts to a giant fish tank—a hydraulic system capable of transporting 440 pounds of live parrotfish (Scarus ssp.) from the Black Sea to the Mediterranean. The wreck also contains 600 amphorae, some with well-preserved fish sauce inside.
Using these studies and a recipe from Geoponica, a 10th century collection of agricultural lore, as a guide, Grainger added salted sardines (Pilchardus sardines) and sprats (Sprattus sprattus) to barrels, put the barrels in a greenhouse, and covered the tops with cardboard. Then she waited two months. What’s surprising, Grainger found, was that the recreated ancient fish sauce appeared to be a lot less salty than its modern Southeast Asian counterparts, with just as much protein. Salt slows down the enzymatic process, so industrial-scale fish sauces today—what you might otherwise think of cheaply made “fast” food—actually take longer to make than the ancient brews. In other words, this old, “slow food” fermented faster.
On one final note, for those of you interested in doing some fishy home-brewing, Ken Albaba, author of the forthcoming Lost Arts of Hearth and Home, told me he made a batch last year. Albaba said it was fun and, moreover, “Not stinky in the least. Almost pure umami in fact.”