Cooking has a lot to do with science

When it comes to molecular gastronomy, I am an agnostic.

I tire easily of rabbits that are made to look like chickens with the assistance of technology.

I am weary of ‘airs’ and foams that claim to capture the essence of coq au vin or Peach Melba or whatever. And I worry that technology is the last refuge of the buffoon – or the untalented chef.

 

   On the other hand, it would be foolish to deny that cooking has a lot to do with science. And research has helped chefs understand how flavours are created, how textures can be manipulated and how heat affects ingredients.

 

   Even home cooks can benefit from some understanding of the science of cooking. All too often we do things in the kitchen without understanding why we’re doing them. And frequently, we are wrong. Here’s a list of some of the things that science can help us accomplish when we cook.

 

Water: All professional chefs know that the taste of the water used in cooking can be crucial to the flavour of the dish. One reason why ITC’s Dal Bukhara tastes the same no matter where you order it – Bombay, Bangalore, Calcutta, Madras or at Delhi’s original Bukhara restaurant – is because ITC has realised that the only way to standardise the taste is to use the same mineral water everywhere. Otherwise, variations in local water play havoc with the taste of the dal.

 

   So, how much difference does water make to dal? We know intuitively that the taste of the water can affect the flavour but scientists have found that it goes beyond that. The acidity of the water also plays a major role in texture and cooking time.

 

   Scientists boiled lentils in three separate pots of water. One pot contained water to which a little vinegar had been added. The second contained pure distilled water. The third contained water with a little sodium bicarbonate.

 

   The scientists found that after boiling, the lentils in pure distilled water were just about cooked. The ones in vinegared water were hard as pebbles. The ones cooked in water with soda added, in contrast, were so tender that they were falling apart.

 

   So, the acidity in water (and much of our water in India is hard and acidic) can be a problem that cooks don’t always take into account. Alkaline water is nearly always better for making dal. Sodium bicarbonate is easy enough to find in the shops. It will make your dal-cooking quicker and easier and you may end up with better dal!

 

Vegetables and fruits: Chefs tell you that once you blanch vegetables you should quickly plunge them into ice-cold water to preserve their colour. This does work but what do you do with vegetables and fruits – apples, pears, avocados, mushrooms etc – that turn brown as soon as you chop them?

 

   Science has demonstrated that one ancient bit of culinary wisdom is valid. You can fight brownness by sprinkling the fruits and vegetables with a few drops of lemon juice. The scientific explanation is long and tedious (the darkening is caused by enzymes called polyphenol oxidases which are neutralised by lemon juice) but remember that vinegar will not work (the phenomenon has nothing to do with alkaline/acid balance). You must use a citric juice.

 

Pasta: All recipe books tell you that the best way to prevent pasta from sticking together in the pot is to add a little olive oil to the cooking water.

 

   The scientific reality is a little more complicated. The key to preventing pasta from sticking together is its protein content. That’s why fresh pastas (which are rich in egg) stick together less. Scientists tried increasing the fat content of the water (by adding olive oil, butter etc) and found it made no difference at all. So ignore that bit about adding olive oil in all the recipe books.

 

   But there is a trick you can use. Add a tablespoon full of vinegar to the water and the pasta will not stick.

 

Potatoes and Milk: French chefs will cook their mashed potatoes in milk even though cooks elsewhere may use water. We think that the French are simply trying to boost the flavour of potato with the taste of dairy.

 

   Perhaps they are. But scientists have proved that cooking in milk will result in mashed potatoes with a better texture. The science is (once again) a little tiresome. When you cook potatoes, the starch granules inside them do not fully expand because of a paucity of inter-cellular water. When you mash the potatoes with a little cooking water, the starch granules will expand but they will do so in a way that yields a sticky mess.

 

   But if you mash the potatoes with milk, the casein in the milk limits the swelling of the starch granules and yields a smoother mashed potato.

 

   So, obviously Joël Robuchon knew a thing or two about science when he perfected his famous dairy-rich mashed potato. (As a general rule, potatoes and milk have many scientific affinities which is why dishes that combine those ingredients tend to work well.)

 

"Research has shown that when an egg is cooked in boiling water (100°C) for 10 minutes, it loses mass and its protein coagulates.  That’s why so many hard-boiled eggs are dry and tough with sandy yolks."

Wine Glasses: Does the taste of wine change depending on which glass you drink it in? There are three answers. The first is the one that most of us would give, which is: “Don’t be so silly.  Of course it doesn’t.”

 

   The second is the one that emerges from tastings conducted by such glass-makers as Riedel who found that different wines tasted better in different glasses and then created special glasses for white Burgundy, red Bordeaux etc. These findings were based on tastings by wine experts.

 

   Now there is a third answer. Scientists at the University of Neustadt in Germany measured aromas, molecules etc to arrive at scientific conclusions. They found that (a) the intensity of how a wine is perceived to taste does change depending on the glass; (b) the higher the bowl of the wine glass and the higher the ratio between the diameter of the rim and the centre of the bowl, the better the wine tasted. And (c) the standard French red wine glass (a bowl that is twice as high as it is wide) called the 1SO glass worked best for both red and white wine. There is no need to buy different glasses for different wines. Just buy the basic ISO glass and you’ll save some money. (But of course, the glassmakers disagree!)

 

Tea Plaque: We have all noticed this: Drink tea for long enough from a pot or a cup and a patina-like stain will come to reside on the surface of the cup or pot. Most of us are used to stains inside our teapots but we have no idea what causes them.

 

   Can science tell us how to stop it?

 

   The answer appears to be: No. The plaque comes from the reaction caused when tea meets hot water and increases greatly when milk is added.  The lowest level of plaque, by the way, is caused by tea with lemon (not milk) because the acidity works against the calcium ions. But if you’re used to milky tea, get used to stained teapots.

 

Seasoning Steak:  I wrote a couple of weeks ago about a controversy at the Singapore Gourmet Festival over how meat is best seasoned. Should you salt a steak for half an hour or so before you cook it?

 

   The British chef Marco Pierre White argued that salting a steak dried it out and made it lose its juices. Another chef Ian Curley disputed this and said that the salt penetrated the steak making it juicier while seasoning it.

 

   Research suggests that the reality is more complicated. Scientists salted steak and chicken for 30 minutes. The chicken lost one per cent of its weight because of lost juices. On the other hand, the steak weighed exactly the same. It had not lost any of its juices or dried out.

 

   But it is not clear that the salt actually seasoned the whole steak either – it may have just remained on the surface.

 

   French scientists used an electron microscope to look for sodium and chlorine inside the meat that had been marinated in salt. They found virtually none. So if the salt had penetrated the steak at all, it had actually passed out of the meat during cooking, making little difference to the flavour. Science is not on the side of either chef: Marco or Curley.

 

Boiling Eggs: This should be easy. Recipe books give us precise cooking times for every kind of boiled egg and 10 minutes is the standard time for hard-boiled.

 

   But research has shown that when an egg is cooked in boiling water (100°C) for 10 minutes, it loses mass and its protein coagulates.  That’s why so many hard-boiled eggs are dry and tough with sandy yolks.

 

   The best way to boil an egg, say scientists, is at a lower temperature: 62°C gives you a liquid yolk while 68°C gives you a hard-boiled egg. But this varies from egg to egg. So the best thing to do – in a home kitchen – is to lower the water temperature below boiling point, keep the egg in the pot for longer and decide, through trial and error, what the right cooking time for your egg is. Professional chefs have thermometers to do this for them. But we can use approximations at home.

 

(I’ve quoted extensively from Molecular Gastronomy by Hervé This, a scientist who is one of the founders of molecular gastronomy. His views are unconventional but backed up by lab research.)