The Royal Society of Chemistry, of which I am proud to be a member, has recently introduced scientific guidelines for making the perfect cup of tea with which to while away this long, hot summer. Their research results have prompted me to wonder whether there might be other food and drink questions whose scientific solution would contribute to our comfort during this long, hot summer. Here are my choice half-dozen:
1. Drink your tea hot to keep cool
This paradoxical advice is often dismissed as an old wives’ tale, but it actually has a reasonable scientific basis. A cold drink, such as iced tea, will certainly cool your insides down, but the main way that we keep cool is through the evaporation of perspiration. It takes five hundred and forty times as much energy to evaporate a given amount of water as it does to raise the temperature of that water by one degree Centigrade. After allowing for the temperature changes in the tea when it is swallowed, a simple calculation shows that if you sweat more than a ninth of what you drink, the advantage is with the hot tea. Hot tea encourages sweating, so the actual advantage is probably even better.
2. How to Pour Champagne
I personally prefer a cold glass of champagne or its cheaper equivalent to any amount of tea when it comes to a summer drink. The problems come when there are a dozen other people to be served before I can get to my own drink. How can I pour the champagne quickly into a sequence of a dozen glasses without having it foam up and spill wastefully over the top?
Science has the answer, which comes from understanding why champagne foams up in the first place. In the bottle, the champagne is loaded with carbon dioxide under pressure. In the open, the carbon dioxide is eager to escape, but it can’t do so unless it can form itself into bubbles. Forming the bubbles needs energy, and this energy comes from microscopic active patches and spikes on the surface of the glass. That’s why the champagne foams up as soon as it touches the inside of a clean glass (It will foam up even sooner if the bottle is opened with the usual ‘pop’, since the ‘pop’ sends a shock wave through the champagne that also starts the bubbles off).
Most people get around the pouring problem by tilting the glass and pouring the champagne slowly. You can speed the whole process up, though, by leaving the glasses vertical on a tray and pouring a little champagne into each – just enough to send foam to the top. By the time that you get to the last glass, the foam in the first glass will have died down, and will also have killed off most of the active points on the glass. Then you can pour the rest of the champagne in quite rapidly without having it foam up over the top.
3. How to Eat Strawberries
Are strawberries better with a dash of basalmic vinegar than they are with sugar? Well, not to me, because I like a bit of grit with my strawberries, and the texture combination of sugar and strawberries is just as important to my enjoyment as is the reinforcement of the sweetness.
But basalmic vinegar can work for some people. There are many ways that one taste can be used to affect another, and sugar is not the only way to reinforce the sweetness of strawberries. Try a tiny touch of salt, which is known to amplify our perception of sweetness (this is why cooks add it to sweet scones). Or try pepper, whose effect on the pain receptors on the tongue can, with some people, become translated into an increased impression of sweetness from a food such as strawberries. Or try basalmic vinegar, whose acidity may have the same effect.
The whole question of how one taste affects another is only just beginning to be explored by scientists. It is a question to which anyone might still make a contribution. So if you experience an unusual effect, or discover an unusual and tasty food combination, let me know!
4. Add Fizz to Your Nibblies
I personally find most nibblies such as crisps rather boring, but I’ve found a scientific way to liven them up. Just sprinkle them lightly with citric acid and bicarbonate of soda. When the crisps are popped into the mouth, these chemicals dissolve and react to produce carbon dioxide bubbles, giving the crisps a surprising, but not unwelcome, lemon-flavoured fizz.
5. Cooking the Perfect Barbeque
Most people overcook their barbeque meat. Australians certainly do, and I ought to know, because I am one. The trick is to let the meat cook itself.
This doesn’t go for the outside of the meat, which needs to be raised to quite high temperatures to induce the complex chemical reactions that lead to that glorious ‘barbeque’ flavour. These reactions need a temperature above 200ºC, but the inside of the meat doesn’t need to be nearly at this temperature – in fact, a comfortable 45ºC – 50ºC, just ten degrees or so above blood heat, will do nicely. So cook the meat for three or four minutes over the red hot coals, then wrap it in aluminium foil and put it to one side for twenty minutes or so (depending on thickness) to let the residual heat penetrate. Then take the foil off, cook the meat for another minute or two over the coals, and serve hot. This method has two advantages – it produces perfect meat, and it leaves time for a glass of red wine while the meat cooks.
6. Alcoholic Elderflower Ice
One of my favourite summer drinks is elderflower, either as the pressé or as the “champagne” that my neighbours and I compete in making. We also boil up some of the flowers in water and freeze the water to make iceblocks that can be added to soda for a refreshing drink when the fresh elderflowers are no longer available.
The problem is that a lot of the flavour oils in the elderflower don’t dissolve in water, and are lost. There is a simple scientific solution. Add 20% vodka to the water before boiling up the elderflowers in it. This dissolves the oils, and adds a belt to the resulting drink in more ways than one.
7. And finally…
It’s the perfect day, and you have in hand that perfect bottle of cold Chardonnay – but no corkscrew. No matter. Just open the bottle the scientific Australian way.
In fact, there are two Australian ways. The first is to fetch a woodscrew from the workshop, together with a screwdriver and a pair of pliers. Use the screwdriver to drive the screw into the cork, and the use the pliers to pull on the woodscrew and lift the cork out. Simple.
But you don’t really need such complex scientific gadgetry as screws and screwdrivers. All that you need is a tree, and a good deal of courage.
I was told about this trick by John Smith, an Australian physicist friend who has such a persuasive manner that I believed that the trick must work. I told all my friends in England about it, but it was only last week that someone at a local party challenged me to actually prove it. Such was my faith in John that I did it without a moment’s hesitation.
It’s very simple. After removing the foil from the neck, and checking that the ‘cork’ isn’t actually plastic (which is much harder to dislodge), hold the bottle horizontally and strike its base firmly against the tree trunk, though not so hard as to smash the bottle. This causes the wine to slap up against the base of the cork, and after twenty or thirty strokes you will see that the cork has begun to emerge. It requires only another dozen or so strokes for the cork to emerge sufficiently far that you can then remove it with your fingers, accept the cheers of the audience and shout yourself to a cold glass of Chardonnay. Warning: Don’t ever do this with sparkling wine, because the cork will come out with the force of a bullet, possibly reducing the number of your friends by one, and certainly wasting a good deal of valuable wine.
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