1 February 2020 | New Scientist | 51SALT curing is an age-old way
of preserving meat and fish
and enhancing flavour. It is
also easy to do at home.
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 oneof 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. ❚Learn the science of curing so you can preserve all kinds of food,
says Sam Wong, including fish, meat and even egg yolksPuzzles
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on the world p53The back pages
Science of cooking Week 5
How to cure everything
Science of cooking online
All projects are posted at
newscientist.com/cooking Email: [email protected]What you need
Salmon
Salt
Sugar
Dill
For next week
White chocolate
Dark chocolate
Thermometer
Hazelnuts
Coffee beans
Sea salt
JAMES
W
INSPEARSam Wong is social media
editor at New Scientist.
Follow him @samwong1
Next in the series
1 Caramelising onions
2 Making cheese
3 Science of crispiness
4 Tofu and Sichuan pepper
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