The science of salt: How to bring out the hidden flavours in your dishes

Knowing how to season properly separates the top chefs from the kitchen amateurs.

In April, The Independent ran a feature revealing some of Britain's best chefs' secret kitchen tips. They ranged from peeling ginger with a spoon to using kachri powder. But perhaps most surprising were the words of Jacob Kennedy and Rowley Leigh. Both cooks' tips involved that most common of kitchen ingredients – salt.

Kennedy mused that "'correct' seasoning, to a chef, is as much salt as you can possibly get into the dish without it tasting too salty." While Leigh suggested that "the biggest difference between professional and amateur cooking is the seasoning… I think a lot of cooks just add salt as an afterthought, whereas professionals use more salt, but they use it earlier as well."

This got me thinking. Almost every recipe I've ever used has either barely mentioned seasoning or just elliptically added "season to taste" at the end of an instruction. If it's so key, surely there's more to it? A flick through almost every cookbook in The Independent's substantial collection didn't offer much more by way of advice.

The only two to feature sections specifically on salt were Hawksmoor at Home, which explained that the London steak restaurants use their own blend of sea salt and smoked salt. The venerable Elizabeth David merely offered, "how you season gives character to your food." So far, so vague...

To learn the wonders of salt – and, more importantly, improve my cooking – I needed the help of a pro. Enter Michael Wignall, head chef of Michael Wignall at the Latymer, the Michelin-starred restaurant at Pennyhill Park, the luxury Surrey hotel that's home to the England rugby team before Tests. During his stay at the Latymer, Wignall has earned and maintained a Michelin star and was recently awarded the maximum five AA rosettes. This is a man who knows his seasoning. I headed down to Wignall's kitchen to get the lowdown on the kitchen's most important ingredient.

Salt brings out the best in food

As you'd expect, Wignall is evangelical about the importance of salt and good seasoning. Overseasoned dishes simply don't make the pass at kitchens like his. And underseasoned ones will be fixed before being served: "It's the basis for any great cooking," he says, "you can have a great dish, but if you've not seasoned it, it's just not there. Salt brings the best out of food and – regardless of whether people say it's bad for you or not – the body needs salt to work properly."

Choose your salt wisely

Thankfully, most home chefs are past the big tub of Paxo table salt and now use sea salt instead. Wignall, whose kitchen gets through a case of the stuff a week, recommends the widely available Maldon sea salt for home cooks. Table salt, full of sulphates and anti-caking agents, is too impure for good food, he suggests – "if you season consommé, or something clear, with table salt, you can see it start clouding because of the agents. It's not good for you."

But Maldon isn't the only salt the Latymer has to hand. When I arrive, Wignall has a spread of different products laid out, ranging from vanilla to smoky Hawaiian lava salt; Cadiz moon salt and the frankly indulgent truffle salt. You can get most of them online or at specialist shops but, for most cooking, Maldon is a good bet.

Remember though, sea salt comes in great big crystals, which makes it much more difficult to add the tiniest pinch to a dish. Either mill the salt or blitz it in a blender to get a finer grade.

Taste, taste and taste again

To make sure your seasoning is correct, you need to constantly taste your food. And not just the sauce or food – but the water or butter you're cooking them in, too. "It's like a sommelier," Wignall tells me as we sniff at his smorgasbord of salts, "you've got to be tasting wine all the time to get your palette accustomed to all the different grapes. It's the same with cooking – you've got to be there saying, 'have you seasoned that? Have you seasoned that? Taste your water.' It's a basic element the home cook overlooks, like not waiting for your oven to warm up."

Be warned, though – if you're dehydrated your body, craving salts, will want to add more. This is how, Wignall says, he can tell if his cooks have been out on the booze the night before – they accidentally add too much salt.

Salt giveth moisture

It might seem counterintuitive, but salt is key to adding moisture to food. "A lot of people think that if you season meat it takes the moisture out," explains Wignall, "but salt actually affects the protein cells' walls. It makes them bigger, so that they actually absorb more liquid. We brine a lot of things, which puts more liquid into them. A piece of meat weighing a kilo will, once it's been brined, weigh more because the water content has increased."

With other things, salt can replace water. About halfway through our masterclass, Wignall pulls out an oven tray with three carrots baked on beds of salt and oil, without any water. Something that, he explains, means that once you've cleared the salt off, you're left with a strong taste of carrots. Rather than water. Later, we taste a beetroot that's been packed in salt and baked in foil – part of a dish that makes up the Latymer's stupendous tasting menu. The taste, for those only used to vinegary beets, is impossibly deep. Try it at home.

Salt can transform an entire dish

As well as enhancing flavour, adding salt can completely transform the character of a dish. To demonstrate, Wignall makes a caramel ganache and invites me to try it. The condensed milk and 60 per cent chocolate mix is tasty, obviously, but once mixed with the Cadiz moon salt, the entire flavour is transformed, creating a sharp, sweet, delicious goo.

Go up, you can't go down

One of the key reasons for seasoning in increments is so you can find the optimum level of flavour and – crucially – not go past it. If you've put too much in, no amount of lemon juice will rescue your dish. "You can always add more if underseasoned," says Wignall "You can never take away. There are some tricks to counteract it – but you're just altering the dish then."

Know when to use it

With some products, salt is vital from the beginning. Others, you need to add it before serving. Wignall shows me two fish dishes. For a piece of halibut he'd season it just before it goes in the pan. Whereas, a scallop is sealed for a minute, cooked in foamy butter, and then seasoned for the last few seconds of cooking. What to season and when seems like something that can only be learnt by constant experimentation and constant tasting. For instance, vegetables such as asparagus will lose their colour if cooked in salted water, but if you cook them without and add salt at the end then the salt will overpower the vegetables. For professional chefs, it's a constant battle to get it just right. For amateurs, well, close enough will do fine. Just don't forget to keep on tasting.