An important thing to consider before you begin your fish pickling adventure is that some fish requires pre-freezing in order to destroy parasites. The EU requires food businesses to pre-freeze fish that are intended to be sold raw or lightly cooked, which means keeping at -20°C for no less than twenty-four hours before serving or processing. There are some exceptions, such as FSA-authorised catches and farmed Atlantic salmon, so it’s worth asking your fishmonger what applies.

General rules include using the best ingredients possible – primarily the freshest, firmest fish and keeping good hygiene by sterilising chopping boards and containers. It’s also important to keep a cool environment and to be exact in how many preservatives to add: that is the balance of salt, sugar and acid. As with all pickles, these staple components are embellished by the introduction of herbs and spices such as bay, fennel, juniper, mustard and dill, through either hot or cold infusion of your pickling liquor.

The most common methods of fish pickling can be categorised into cooked (or soused), raw and pre-cured (where the fish is salted or brined). Pickling raw fish generally takes a minimum of five days. Some fish that has been pre-cured requires de-salting in water for twenty-four hours and then pickling for a minimum of twenty-four hours. Cooked fish requires even milder marination because it contains fewer bacteria, but this results in ‘less development of flavour and texture,’ observes Harold McGee.

Nordic-style pickles are typically pre-cured and then steeped in sweetened vinegar. Harold McGee states that these Northern European pickles are commonly made over one week. By comparison, Japanese shime saba is salted for twenty-four hours then pickled for twenty-four hours.

Jane Grigson recommends a quick salting method using ten percent brine, submerging fillets for a minimum of three hours before pickling right away. Alternatively, Hugh Fearnley-Whittingstall’s pickled herrings, adapted from Rick Stein, are salted for only half an hour in a much stronger brine (two kilos of salt to six litres of water), then pickled in spiced wine and wine vinegar for one to three days. Fully dry-salted fish can be left for three months or more.

It’s through playing about with these curing ratios that chefs can achieve appealing differences in flavour and texture. The transformative chemistry of curing and pickling is no more fascinating than when used to influence the delicate flesh of fresh fish, so it’s a fascinating method to experiment with.