How to Make Traditional (Aged) Fish Sauce

This recipe appeared in its original form in Insane in the Brine: The Official Cookbook. Although some recipes are now found here, the book still contains about a hundred recipes not available anywhere else. To avoid ads in my articles, scroll to the very bottom where you can always find an ad-free, printable/downloadable (as .JPG) recipe card.

Fish sauce is one of the oldest and most universal flavor enhancers in the world, not to mention a standard ingredient for making kimchi and countless other Korean (and Southeast Asian) dishes more broadly. Long before modern condiments like soy sauce, ketchup, or Worcestershire existed, cooks in ancient Greece and Rome relied on garum, a naturally rendered (not to say fermented) sauce made from whole small fish and salt. Its rich umami flavor was so prized that it became a major trade commodity across the Mediterranean. Some historians believe early Mediterranean garum and Asian fish sauces may have influenced one another through ancient trade routes, while others see them as parallel culinary inventions. Either way, the technique remains simple, safe, and incredibly effective.

Today, fish sauce ranges from inexpensive everyday bottles to rare, long‑aged artisanal versions. You can make your very own high‑quality fish sauce at home with just fresh fish, salt, and time. Using the freshest fish you can find, you could make something any commercial brand would be jealous of. The long‑aging method requires almost no active work, and because the salt level is high enough to prevent botulism, it is safe for room temperatures. The result is a clear, amber, deeply savory sauce.

Is garum a fermented food?

Although often grouped with fermented foods, garum is actually driven mostly by enzymatic breakdown rather than active microbial fermentation; the high salt level halts bacterial activity within days, and the long aging period allows the fish’s own enzymes to slowly transform the mixture into a clear, deeply savory sauce. Therefore, typical fermentation equipment such as an airlock or the notion of “burping” a jar absolutely does not apply here. The specifics for the process are offered below.

This recipe walks you through the entire process, from preparing the fish to aging, straining, and bottling. It is a traditional technique adapted for modern kitchens, with clear food‑safety guidance and optional variations for flavor. If you’ve ever wanted to make your own fish sauce or explore ancient food preservation traditions, this method produces a reliable, richly flavored condiment that is surprisingly easy and safe to make.

Salt Levels and What They Mean

• 10–12% salt: safe minimum for room‑temperature fermentation; produces a more intense, deeply savory sauce with higher enzymatic activity
• 15–20% salt: ideal balance of safety, clarity, and flavor; steady fermentation with a clean, rich final sauce
• 20–30% salt: extremely safe and very stable; produces a salt‑forward sauce used in smaller amounts
• Below 10% salt: not safe for long‑term room‑temperature fermentation

Botulism spores cannot germinate above 10% salt, which is why the lower bound is non‑negotiable.

Yield:

10-12 fl. oz.

Shelf life:

Approximately 10–12 fl oz finished fish sauce
(about 300–350 ml; fits a standard 12‑fl‑oz woozy bottle)

Equipment:

• Knife & cutting board
• Large mixing bowl
• Kitchen scale
• Kitchen gloves
• Sanitizer (such as OneStep) or vodka/grain alcohol
• ½ gallon jar
• Canning funnel (suggested)
• Paper towels
• Packing tape
• Optional: fermentation weight

After aging:

• Large mesh strainer spider or colander, with bowl
• Fine mesh straining bowl/stand lined with muslin or coffee filter (or line the colander or spider above with muslin)
• Bottling funnel (optional)
• Glass storage container

Ingredients:

• 2.5 to 3 lbs. small, whole fresh fish (1130 – 1360g), e.g. anchovy, smelt, herring, mackerel, and/or small fresh whole shellfish
• 10% – 30% additive-free salt by weight of the fish (see discussion above)
• Optional: sugar 5% by weight of the fish
• Aromatics as desired (e.g. a few tsp chopped ginger, herbs, garlic, whole spices, etc.)

Directions:

1. Wash the jar, knife, cutting board, and mixing bowl with hot soapy water. Put on kitchen gloves. Sanitize the jar with a no‑rinse sanitizer (like OneStep) or wipe it thoroughly with vodka or grain alcohol. You may also boil the jar in a saucepan of water and keep it hot until needed.

2. Rinse the fish under cold water. Drain well and pat dry. Weigh the whole fish in grams to determine the amount of salt (and optional sugar). If using aromatics, weigh them and include them in the salt percentage.

3. Chop each fish vertically into 3–4 pieces, keeping the heads, bones, guts, and tails. These parts contain the enzymes that drive fermentation.

4. Combine the chopped fish, salt, and any optional ingredients in a mixing bowl. Mix thoroughly so every piece is evenly coated.

5. Make sure the jar is dry and cool. Using a funnel, pack the salted fish mixture into the jar and press it down firmly to remove air pockets. Over the next several days to weeks, the salt will draw out liquid and create a natural brine. If the fish is not fully submerged after 2–3 weeks, you may briefly open the jar and add a glass fermentation weight.

6. Seal the jar tightly. Wrap the lid completely with packing tape as an added assurance to prevent oxygen from entering. Store the jar at room temperature (60–80°F) in a pantry or enclosed outdoor cabinet. Let it ferment for 1 to 2 years. (A longer wait period will result in a smoother final product; however, though a usable product can be obtained waiting at least 6 months, at least a year is suggested.) A layer of lipids may form on the surface during aging; this is normal.

7. After aging, open the jar and strain the liquid through a mesh strainer into a bowl or jar. This is just to remove any pieces and debris; the finishing fine straining process in coffee filters or the like (Step 8) will give the characteristic dark-but-clear liquid. (If desired, mix the solids with a 20% salt brine and age for another 3–6 months to produce a weaker second batch.)

8. Strain the liquid through muslin or coffee filters at least a couple times, using a fresh filter each time. The finished fish sauce should be clear, amber, and free of sediment. It will smell strongly of fish but should not smell rotten. If a layer of fat accumulates at the surface of the liquid, the straining process can be repeated one more time.

9. Transfer the finished sauce to a clean glass bottle. Keep it sealed and store it in the refrigerator for best flavor and color retention.