What you need
Salmon
Salt
Sugar
Dill
SALT curing is an age-old way of preserving meat and fish and enhancing flavour. It is also easy to do at home.
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It works by drawing water out of microbial cells that cause food to spoil, killing them or slowing their growth. The meat or fish also loses moisture, concentrating its flavour. This is further improved in meat by enzymes continuing to break down proteins over time. This produces glutamate, creating an enhanced “umami” taste – a subject we will revisit later in the series. The salt also dissolves myosin, the protein that contracts muscle fibres, making the flesh more tender.
Cured meats are the subject of health concerns. These are linked to nitrates, which are often added to the cure to preserve meat’s red colour. They do this by preventing oxidation of red myoglobin proteins, but they can form nitrosamines, a potential carcinogen, when heated. You can avoid the risk by curing your own meat without nitrates, but it must be said that the results may end up an unattractive grey colour.
Gravlax, on the other hand – a cured salmon dish originating in Scandinavia – looks and tastes amazing, and is very easy to make.
It was originally created by burying fish on a beach until it fermented – the “grav” in gravlax comes from the Swedish word for grave. But this results in flavours that might be described as challenging: food writer Anthony Bourdain said hákarl, a fermented shark dish from Iceland, was one of the worst things he ever tasted.
Modern gravlax involves little or no fermentation, however, and the fish is only lightly cured. This is enough to extend its shelf life by a few days, but not weeks.
Start with a 1-kilogram piece of salmon and remove any pin bones with tweezers. Mix 50 grams of coarse salt and 50 grams of sugar, then add some spices if you like: a tablespoon of peppercorns, coriander seeds or caraway seeds, ground in a mortar, works well. Rub the mix into both sides of the salmon, then place it on a bunch of dill in a dish, skin side down. Top it with more dill and a plastic covering, then put a heavy item on top to press down on the salmon.
Keep it in the fridge for a day, then turn the salmon over, repack and refrigerate for another day or two. All you need to do then is scrape off the dill, cut some slices and serve with rye bread.
Egg yolks can also be cured with salt and sugar to create a firm and richly flavoured ingredient that is a bit like a cheese. Simply mix equal amounts of salt and sugar and put some of this in a lidded container. Place egg yolks onto the salt and sugar, then bury them with the remaining mixture and cover. After a week, remove the yolks, rinse them and dry them in an oven at 90°C for 30 minutes. Grate or thinly slice the yolks and add to meat, vegetables or pasta dishes. They should keep in the fridge for two weeks.
For next week
White chocolate
Dark chocolate
Thermometer
Hazelnuts
Coffee beans
Sea salt
Next in the series
5 Gravlax and curing
6 Tempering chocolate Make glossy chocolate with a satisfying snap
7 Umami and flavour
8 Perfect pancakes
9 Kimchi and fermentation
10 Sourdough bread
All projects are posted at Email: cooking@newscientist.com
