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Fish sauce is the mother of all condiments. Most prevalent today in Southeast Asian cuisines, 2,000 years ago it was the favorite condiment of classical Rome. Then and now, fish sauce is a strategy used in coastal areas to turn abundant small marine life into a nutritious, stable, and flavorful food resource. Fish sauce is essentially liquefied fish; the cells of the fish are transformed from solid to liquid state by enzymatic digestive processes described in the scientific literature as autolysis [self-digestion] and hydrolysis [digestion into water]. Reflecting on the fact that this process spontaneously begins in salted fish if not quickly dried, historian H. T. Huang writes that fish sauce “was an invention that was just waiting to happen.”
Use fresh whole small saltwater fish, mollusks, or crustaceans with their viscera (organs). “The enzyme or enzymes responsible for fish protein hydrolysis are chiefly located in the visceral organs,” reports Keith Steinkraus. According to a team of researchers investigating the production of Thai nampla fish sauce in the Journal of Agricultural and Food Chemistry, fish are left at ambient temperatures for 24 to 48 hours prior to salting. “This actually initiates the fermentation process.”
Next, add salt and stir thoroughly to evenly distribute it. Heavy salting is critical to protect the fish from rapid putrefaction and growth of potentially dangerous bacteria, including C. botulinum. Most contemporary styles of fish sauce incorporate salt at a proportion of no less than 25 percent (by weight); some use considerably more. Food historian Sally Grainger notes that ancient Roman recipes for fish sauce used much less salt, approximately 15 percent. She attributes the higher salt levels in modern fish sauce to “fear of dangerous bacteria such as botulism.” However, the International Handbook of Food-borne Pathogens states that 10 percent salt is enough to prevent the risk of botulism in fish in “the aqueous phase” at room temperature.
Typically no water is added to fish sauce. Salted fish are placed in a crock, barrel, tank, or other vessel, and weighted down — as is sauerkraut — to expel air pockets and keep solids from floating to the top. Initially, salt pulls water from the fish cells by the process of osmosis; then enzyme and microbial processes cause hydrolysis. Depending upon temperature, salt content, and tradition, ?sh sauces ferment for between 6 and 18 months, with periodic stirring. The recipe I followed, for a Filipino-style fish sauce called patis, sent to me by my friend Julian (whose mother was from the Philippines), instructed to ferment in a warm place until a “desirable aroma has developed.” The color also darkens as time passes, as more of the fish solids liquefy. I left mine to ferment for about six months. It tasted like fish sauce, though I cannot claim to be a connoisseur with a discerning palate. Keith Steinkraus reports on patis production that the fermentation time ranges from six months to a year.
In the Filipino tradition, the fish sauce is drained from the solids. The liquid sauce is patis; the residual solids, with remaining bones removed, are ground into a paste called bagoong, also used as a condiment. Fish sauce may be used raw after straining or is often pasteurized before bottling, sometimes with the addition of alcohol.
Microbiologists have debated the importance of fermentation in the production of fish sauce. “Generally, the number of bacteria steadily decreases in the fish following the addition of salt,” writes Steinkraus. Nonetheless, microbial analysis has established that salt-loving (halophilic) bacteria “are likely playing an important role in the maturation and development of typical fish sauce aroma and flavor.” This is the basic process. A Roman cuisine enthusiast, Heinrich Wunderlich, suggests speeding fermentation of garum (classical Roman fish sauce) by using a yogurt maker that keeps the fish and salt at 104 degrees F/40 degrees C. With whole small fish, or just innards, 15 to 20 percent salt by weight, and stirring once a day, he writes that the fish liquefies in three to five days, leaving a bare skeleton. Flavor develops more slowly, and is fully developed, even in the yogurt maker, only after a few months have passed. There are many variants on basic fish sauce, some using specific fish, mollusks, or crustaceans; others with added ingredients including sugar, tamarind fruit pulp, pineapple, and grains, either molded (such as koji or qu), malted, in the form of lees (the solid residue from making saké), or even outer husks. There are also hybrid fish-soy sauces incorporating soy koji into the fermenting mix.
More from The Art of Fermentation:
From The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from around the World by Sandor Ellix Katz, © 2012 by Sandor Ellix Katz. Reprinted by arrangement with Chelsea Green Publishing, White River Junction, VT.
The Art of Fermentation is the most comprehensive guide to do-it-yourself home fermentation ever published. Sandor Katz presents the concepts and processes behind fermentation in ways that are simple enough to guide a reader through their first experience making sauerkraut or yogurt, and in-depth enough to provide greater understanding and insight for experienced practitioners. With two-color illustrations and extended resources, this book provides essential wisdom for cooks, homesteaders, farmers, gleaners, foragers, and food lovers of any kind who want to develop a deeper understanding and appreciation for arguably the oldest form of food preservation, and part of the roots of culture itself. Order from the Fermentation store or by calling 800-234-3368.
