Home › The Principles of Cookery › Mackerel, Potted
Mackerel, Potted
Choose fresh fish of a moderate size. Cut off the heads and tails, remove the bones, take out the dark brown bitter portion near the heads, and divide the flesh into convenient-sized pieces. Lay these in a jar, season with pepper and salt, cover with vinegar, and put shallots and bay-leaves on the top, one of each for four fish. Cover closely and bake gently for two hours. Serve cold.
This is soused mackerel under an older name: the fish is baked slowly in vinegar until the flesh sets firm and faintly pickled, then eaten cold. Two things decide the result — genuinely fresh fish and a low, steady oven.
- "Potted" here means soused, not potted in butter"Potted" here means soused, not potted in butter. There is no pounded flesh and no clarified butter cap; expect firm vinegar-cured fillets, closer to Scandinavian or Welsh soused mackerel than to potted shrimps.
- "Bake gently" is 300F"Bake gently" means a low oven — around 300F (150C) is a reasonable modern reading, though the recipe gives no temperature. The point is to set the flesh in the acid without letting the vinegar boil, which would shred the fillets and drive off the aromatics.
- Two hours is for whole-sided piecesTwo hours suits thick pieces — the recipe has you bone the fish and cut it into convenient-sized pieces, so the timing depends on how thick those are. Thinner fillets will be done well inside two hours; test by whether the flesh has gone opaque and firm right through, and pull them before they collapse.
- The dark bitter portionThis is the blood line and the dark red-brown muscle along the backbone near the head, plus any trace of kidney tissue in the belly cavity. In an oily fish it carries the strongest flavour and turns rank first, so scrape it out with a spoon rather than trusting a rinse.
- Vinegar and the vesselMalt vinegar at around 5 per cent acidity is the period choice; cider vinegar works. Dilute one-third with water if you want it milder. Use glass, glazed stoneware or an enamelled pan — uncoated aluminium, cast iron and copper will react with two hours of hot acid.
- Covering closelyA tight lid or a double layer of foil crimped down keeps the fish submerged and stops the vinegar reducing. Do not use a sealed preserving jar with a clamped lid in the oven; the recipe wants a covered dish, not a canning process.
- Freshness is not optionalMackerel is among the fastest-spoiling fish sold, and the vinegar bath will not rescue a tired one. Look for bright, stiff fish with clear eyes, and cook the day you buy.
- This is not a preserveDespite the jar and the vinegar, nothing here is measured or heat-processed for shelf storage. Keep it covered in its liquor in the refrigerator and eat within three days.
- YieldThe recipe gives quantities only as a ratio (one shallot and one bay leaf to four fish). Four mackerel would make a cold dish for four to six with bread and butter.
Souring oily fish in vinegar is one of the oldest ways of buying a few extra days out of a catch that will not keep, and it survives all round the North Sea and Baltic — as soused mackerel and herring in Britain, as rollmops and *Bratheringe* in Germany, as *escabeche* along the Atlantic coast of Spain and Portugal. Mackerel came into cities in glut and fell in price quickly, and it is traditionally said to have been among the few fish London street sellers were permitted to cry on a Sunday; a household faced with cheap mackerel either fried it that evening or soused it. The dark strip the recipe tells you to cut away is the fish's blood-rich muscle, and it is also the tissue where spoilage shows first, though Victorian writers explained it as bitterness.