Cold sauces & condiments
Shrimp oil (Fuzhou-style fish sauce)
虾油 · A traditional Fujianese liquid seasoning made by salt-curing and prolonged sun-fermentation of small sea fish and shrimp, then extracting, boiling and clarifying the amber-red protein-rich liquor. Long consumed across Fujian, Chaoshan, Vietnamese and Southeast Asian cuisines, it functions as a salt-and-savory seasoning used at nearly every meal in Fuzhou households.
The formula
原料:盐=100:16~20; 抽提用5~6%食盐水冲缸
Total salt is 16–20% of raw-material weight over the long cure; extraction uses a 5–6% brine equal to (raw material weight minus first-skimmed floating oil).
Identity
- Orange-red (橙红) clear liquid body, free of sediment
- Pronounced savory-sweet (鲜) aroma with a characteristic 'xiang hun' (香荤, sea-meaty) fragrance when well-made Mintian-style
- Salt-cured and long-sun-fermented, never distilled
- Rich in free amino acids from endogenous protease hydrolysis of fish/shrimp protein
- Defined heritage product of Fujian coastal fishing towns, notably Fuzhou's Mintian (民天) brand
Ingredients
| Base | Small sea fish (小海鱼 / 小杂鱼, e.g. small green-scaled sardine 小青鳞鱼, 三脚鱼/三角绮, anchovy-like trash fish) | Primary protein substrate; cheap, low commercial-value species are preferred so the protein is hydrolyzed into amino acids rather than eaten whole. |
| Base | Fresh shrimp (鲜虾 / 虾) | Provides the signature shrimp-essence aroma and shrimp-astaxanthin red color; small whole shrimp, washed in the sea-water drag of the net. |
| Seasoning | Salt (食盐) | Total curing salt = 16–20% of raw-material weight, added gradually over the first month; controls wild fermentation and selects halotolerant enzymes. |
| Liquid | Local well water (古井水) | Fuzhou Mintian uses mineral-balanced ancient well water both to dissolve salt for brine addition and as the final extraction medium; soft, clean well water is credited for the brand's 'xiang hun' character. |
Method
- 1Clean raw materials in the month before Qingming (清明前一个月): wash small trash fish to remove mud and grit; wash shrimp at sea in the net before landing and transport in baskets.Cold early-spring weather plus clean, fresh raw material keeps the mixed endogenous enzymes active without spoilage before salting.
- 2Load cleaned fish+shrimp into wide-mouthed, big-bellied earthenware jars (瓦缸) to about 60% of jar volume, then leave open to sun and dew for 2 days; stir twice daily (morning and evening) and once red foam appears on top (3–5 days), begin adding salt — 1–2 jin per stir — until 15 days have passed, then continue stirring once daily and taper salt by ~5%, finishing at the prescribed 16–20% total.Sun-dew cycling plus daily agitation draws fish/shrimp body enzymes (trypsin, chymotrypsin, carboxypeptidase, lipases) into hydrolyzing the proteins into free amino acids while salt screens out spoilage microbes.
- 3Continue sun-and-dew fermentation (曝晒发酵) for months, covering the jars with bamboo-and-leaf or plastic rain hoods during rain; stir daily — the longer and more frequent the stirring and the stronger the sun, the more the fishy smell dissipates and the darker, oil-layered paste becomes.Extended photo-thermal exposure completes enzymatic hydrolysis, lets volatile fishy amines off-gas, and develops the orange-red top oil layer that signals fermentation is finished.
- 4After the 'fú tiān' dog-days of summer into early autumn, skim the floating oil, then pour in a 5–6% salt-water brine equal to (raw-material weight minus first-skimmed oil); stir 3–4 times and let settle so the liquor separates from the residue.Cold brine washing re-dissolves the salty amino-acid liquor trapped in the paste while keeping residual solids as cake, giving a clean first liquor (生虾油).
- 5Filter the liquor by lowering a bamboo basket (竹篓) into the jar so the liquid filters through into the basket, then ladle out; blend successive batches to uniformity.Bamboo-basket gravity filtration yields a clear raw oil without pressing bitter solids; the Mintian set uses 竹笆 (bamboo mat) drainage and wooden paddles (木撞).
- 6Boil the raw shrimp oil in a pan, skim foam, settle, filter again, then expose the clarified liquor to further sun in storage jars (optional final maturation), before sterilizing and bottling.Heat kills residual microbes and enzymes that would otherwise keep working in bottle, fixing color (orange-red), aroma, and amino-acid profile.
Techniques that matter
Sun-and-dew fermentation (日晒夜露 / 曝晒发酵)
Slow ambient temperature cycling drives endogenous proteases to hydrolyze fish/shrimp protein into free amino acids, the source of the sauce's umami.
Graduated salt addition (分期加盐)
Adding salt in stages over the first month lets halophilic enzyme activity peak early while preventing putrefaction, yielding clearer, more fragrant sauce than single-shot salting.
Bamboo-basket gravity filtration (竹篓/竹笆沥滤)
Gentle non-press filtration avoids squeezing bitter residues into the liquor, preserving clarity and a clean savory finish.
Variations & derivatives
Mintian (民天) shrimp oilFuzhou, Fujian
Most famous heritage version; founded 1931 by 王贤镇; uses local 古井 (ancient) well water and modernized hygiene, certified Fujian Intangible Cultural Heritage.
Xiamen/Hokkien shrimp oil (虾油, heⁿ-iu)Xiamen, Fujian
Coastal Xiamen variant with a slightly sharper salt profile and a smaller, more shrimp-led aroma; used daily as a dip for 蚝仔煎 and boiled vegetables.
Chaoshan shrimp/fish sauceChaoshan (eastern Guangdong)
Closely related southern Fujian style, often using anchovy-dominant raw material, exported via overseas Chinese to Vietnam (where it became nước mắm) and Southeast Asia.
Industrial fish sauce (现代工业化鱼露)Nationwide Chinese coastal factories
Uses controlled-temperature tanks instead of open jars; standardized against the GB national technical specification for fish-sauce processing.
Used in these dishes
Substitutions
- Fuzhou shrimp oil (虾油) → Vietnamese nước mắm — Closest flavor analog; use roughly the same volume; lacks the deeper red shrimp-astaxanthin hue but delivers similar salt-and-savory backbone.
- Fuzhou shrimp oil (虾油) → Thai nam pla — Lighter, more sharply salty and slightly sweeter; reduce quantity by ~25% in dipping-sauce roles.
- Fuzhou shrimp oil (虾油) → Korean aekjeot (액젓) or Japanese iriko shoyu — Acceptable umami swap but markedly different aromatic profile; only suitable as background seasoning, not as a dip.changes result
Troubleshooting
Persistent fishy / ammonia smell in finished sauce
Insufficient sun exposure or insufficient stirring during the open fermentation stage, so volatile amines were not driven off and oxidation is incomplete. → Return the raw oil to a shallow open jar and continue sun-and-dew exposure with twice-daily stirring for several more weeks before reboiling.
Overly harsh saltiness, lacking round umami
Salt added too quickly or in too high a single dose early on, which halted enzymatic hydrolysis before amino acids built up. → Dilute with a small amount (≤10%) of weak well-water brine and re-ferment briefly in sun; or blend with a milder, longer-aged batch.
Cloudy sauce with floating residue in bottle
Filtration skipped the bamboo-basket step or the brine-wash was too vigorous, suspending fine solids. → Re-settle in a cool place 24–48 h, then siphon the upper clear layer through bamboo or fine cloth; reboil and rebottle.
Sour / putrid off-aroma or surface mold bloom
Total salt fell below ~16% of raw material, allowing halotolerant spoilage organisms to grow, or rain entered uncovered jars. → Discard the batch — under-salted fish/shrimp ferment cannot be safely rescued once putrefaction has set in.