Modernist

Garum Moderno · Koji-Accelerated Fermented Fish Sauce

A modernist home-made umami-concentrate — white fish trimmings + koji rice + salt + water, fermented at 60°C for 10 weeks, producing a deep-amber liquid that tastes like the most complex possible fish sauce crossed with the most intense dashi. The koji (Aspergillus oryzae) accelerates enzymatic breakdown of fish proteins to ~1/10 the time of traditional Roman-era garum (which took 3-6 months). Temperature-controlled in an incubator or SV bath; produces ~500 ml from 1 kg of fish trimmings. Use sparingly (5-10 drops per dish) as a flavor-multiplier; replaces fish sauce, soy sauce, or concentrated stock in dozens of applications. 10 weeks mostly-idle + 2 hours of active work; the modernist umami-stash most cooks only dream about making.

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Pantry Staple · Flavor Multiplier · Umami Base
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Fish trimmings (any white-fleshed fish) + koji rice
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~500 ml (flavor-multiplier; lasts 6+ months)
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10 weeks

The Sauce That Rome Made + The Enzyme That Accelerates It

Garum was the dominant condiment of the Roman Empire — fermented fish sauce made by layering whole fish + salt in amphorae + aging in the sun for 3-6 months. Similar sauces (liquamen) survived into the Byzantine era + reach their modern descendants in Southeast Asian fish sauce (nuoc mam, nam pla), Japanese ishiru, and Korean saeu-jeot. All follow the same principle: autolysis (self-digestion) of fish proteins via endogenous enzymes + salt-protection against pathogens, producing a deep-amber protein-rich liquid with intense umami.

The modernist adaptation (developed + popularized by the Nordic foraging-school + others from 2015 onward) uses koji — the Japanese mold Aspergillus oryzae grown on rice — as an enzymatic accelerator. Koji produces proteases that break down proteins ~10x faster than endogenous fish enzymes alone. Combined with temperature control (60°C warm incubation), the fermentation time drops from 3-6 months to 8-10 weeks. The result is genuinely close to the best Southeast Asian fish sauces, with a cleaner character + no muddy old-fishy notes.

The process requires patience + equipment: a container that can hold 60°C consistently for 10 weeks (SV bath + insulated cooler, or a dedicated fermentation chamber). Home cooks without SV setup can use a yogurt maker (some models hold 55-60°C) or modify a slow cooker to maintain the target temperature. The ingredients are simple + affordable: fish trimmings (often free at a fishmonger), koji rice ($15-25 per kg online), non-iodized salt, water. The result: ~500 ml of liquid that costs ~$15 to make but would cost $80+ to buy at artisan quality.

Applications: 5-10 drops into any soup, braise, sauce, or sauté for instant umami depth. Replace a dash of fish sauce in Southeast Asian recipes. Add to tomato sauces, risottos, stews. Substitute for soy sauce (lighter flavor). Brush onto meats before the final fire for added savory depth. The garum is a flavor-intensifier — a few drops transform an already-good dish into a Great one. Once made, lasts 6+ months refrigerated.

Ingredients

for ~500 ml (flavor-multiplier; lasts 6+ months)

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Everyday

The Ingredients

1 kg fish trimmings — any white-fleshed fish (cod, snapper, flounder, halibut, haddock). Free from a fishmonger; save over time in freezer until you have 1 kg.
300 g koji rice — GEM Cultures Koji Rice or Cold Mountain Koji Rice (both online, $20-30/kg)
80 g non-iodized fine sea salt — Diamond Crystal or Morton Kosher (must be non-iodized)
600 ml filtered water

No Limits

The Ingredients (Tier B)

1 kg high-quality fish trimmings from a premium fishmonger (Casablanca Seafood or Marky's in Miami — white fish preferred)
300 g koji rice (fresh if sourceable, dried otherwise)
80 g Sal de Ibiza or standard fine sea salt (non-iodized)
600 ml filtered water

The Equipment (Tier B — the difference-maker)

Dedicated fermentation chamber ($200-500 from home-brew supply companies) that holds 60°C ±0.5°C reliably for 10 weeks. Alternative: modified wine-cooler fridge with commercial temperature controller. Worth it for serious fermentation practice.
Heavy-duty gallon-size glass jar with airlock lid
Dedicated fermentation thermometer (ambient temp monitoring)

Mise en Place

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Fish trimmings collected + thawed (freeze-thaw in batches until 1 kg accumulated)
Koji rice measured
Salt measured
Water measured + at room temp
SV bath + cooler setup ready (60°C verified)
Jar sterilized (boil 5 min)

Method

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Phase 1 · Setup + Combine — 30 minutes

Ensure SV bath + cooler setup is at 60°C + stable for 30+ minutes.

Sterilize the 1-gallon jar (boil 5 minutes ).

In the sterile jar: combine 1 kg fish trimmings + 300 g koji rice + 80 g salt + 600 ml water.

Stir thoroughly to ensure salt is dissolved + ingredients are roughly combined.

Seal with an airlock lid. Transfer the jar to the 60°C cooler/SV setup.

Label with start date. Plan for 10 weeks of wait.

Phase 2 · Fermentation + Weekly Checks — 10 weeks

Week 1: No visible change. Initial enzyme activity. No action needed.

Week 2-3: Fish pieces visibly breaking down. Water darkens to light-yellow. Weekly 10-min check: verify 60°C, check for mold (skim if present), note any smell changes.

Week 4-5: Fish is primarily broken down; koji rice is partially dissolved. Liquid is amber. Smell is strong but clean-fermented, not rotten.

Week 6-7: Deep amber liquid. Flavor clearly evolving. Taste cautiously: should be intensely umami, slightly sweet, complex.

Week 8-9: Darker amber liquid. Koji mostly dissolved. Flavor at peak.

Week 10: Ready to strain. Liquid is deep amber, smell is strong-umami-clean, flavor is intense + complex.

Weekly checks are essential for quality assurance. If temperature swung below 50°C or above 65°C at any point for an extended period, the batch may be compromised.

Phase 3 · Strain + Store — Overnight

After 10 weeks: set up straining. Line a fine-mesh strainer with 3 layers of cheesecloth, placed over a large bowl.

Pour the fermented mixture through the cheesecloth slowly.

Let drip undisturbed overnight (8-12 hours). DO NOT squeeze.

The liquid that drips through is the finished garum — deep amber, slightly viscous, intensely umami.

Transfer the clear garum to sterile 500-ml storage jars (sterilized by boiling). Label with date.

The strained pulp (fish + koji residue) is still flavorful — grind in a food processor + use as a compound paste for marinades, or discard.

Keep garum refrigerated. Shelf life: 6+ months. Peak flavor in the first 2 months.

Phase 4 · Use + Application

Standard usage: 5-10 drops into any savory dish — soups, braises, stews, stir-fries, pasta sauces, bean dishes, grilled meats.

Acts as: umami multiplier (deepens existing flavors without shifting direction), protein flavor-enhancer (brings out savory notes in any cooked protein), modernist substitute for fish sauce or concentrated stock.

Applications: replace a splash of fish sauce in Southeast Asian dishes. Add 10 drops to tomato sauce to deepen. Brush onto steaks before final sear. Add to bean stews (fabada, callos) for 10 drops per pot.

Compatible with: Spanish cuisine (subtle), French cuisine (excellent), Italian cuisine (very good), Asian cuisine (compatible, varies by regional specifics), modernist/fusion cooking (ideal).

Not compatible with: very delicate vegetable-only dishes where the fish note would dominate; sweet-only desserts.

Timeline

Week 1 T-0 Mix ingredients + transfer to sterile jar; submerge in 60°C bath
Week 2-3 Active digestion begins — fish is breaking down; water clear but yellow-tinted
Week 4-5 Mid-ferment; smell is present but not fishy; liquid darkening to amber
Week 6-7 Flavor development; smell is complex (fish + umami + slight sweet-fermented)
Week 8-10 Ready to strain; flavor deep + amber color developed
Week 10+ T-0 Strain overnight; transfer to storage jars; refrigerate
Week 10 T+8h Garum ready; 500 ml of amber liquid in storage