New Scientist
Summer is the season for open-air concerts, where the ticket reads “bring a picnic and chairs”. The picnics in our part of rural Somerset are competitive affairs, with elaborate candelabra and equally elaborate dishes on display. At one recent concert my wife Wendy, tired of being upstaged, turned to me and said “You are a food scientist. Why can’t you use science to liven up our picnics?”
It seemed a fair challenge. As we listened to the music of Acker Bilk, I began to work on ideas for a scientific picnic that should upstage all the others.
In my vision of next year’s picnic, our neighbours look on with envy at a table centerpiece made from meringues cooked in an oven full of helium. The multi-coloured meringues float like balloons on the ends of strings. When the time for dessert arrives, guests are given a gun filled with cream and custard and afforded the chance to shoot down the meringue of their choice and catch it in their plate, turning the sweet course into a new country sport.
The table has an array of small magnets glued to the underside, with north poles pointing upwards. The plates are glued back-to-back in pairs, with a similar array of magnets between each pair. Some, holding the meats and pies, are arranged with south poles down, and hold firmly to the table. Other pairs, holding the light salad ingredients, are inverted and hover permanently above the table. Such stable magnetic levitation was long thought to be impossible, but my colleague Professor Michael Berry has recently performed the difficult analysis which shows that it is possible under a restricted set of conditions if the object is spinning. The slowly rotating levitated plates provide another focus of public attention, as well as keeping the food away from ants.
Champagne is on offer, but not in its traditional liquid form. Stimulated by the thought of a competitive picnic, I have found a way to make it into champagne jelly, with the advantage that the champagne is not lost if the glass is knocked over. Champagne by the spoonful is a novel experience for our guests, who delight in the experience when the trapped bubbles release their delicious fizz as the jelly is eaten.
Another fizzy experience is provided by crisps lightly sprinkled with a mixture of citric acid and sodium bicarbonate. When the crisps are popped in the mouth, these two materials dissolve and react to produce a surprising, but not unwelcome, lemon-flavoured fizz.
The whole picnic is a surprise based on science, some of which Wendy and I learned during a meeting between chefs and scientists in Erice, Sicily. We have provided ham sandwiches flavoured with a mixture of garlic and coffee, and cockles dipped in white chocolate. Both of these combinations, inventions of leading chef Heston Blumenthal, work by fooling the brain, which oscillates between the two flavours but cannot mix them. Tobacco-flavoured dark chocolate, another of Heston’s creations, provides a similar experience, and is offered to those who wish to smoke without offending their neighbours.
Another sensory experience is provided by the checked tablecloth, whose construction is based on the IgNobel Prize-winning concept of the “scratch and sniff” business suit, developed by a Korean businessman intent on concealing the aromas of a night out from his wife. Each square of our tablecloth provides a different aroma. We learned in Erice that the contribution of aroma to flavour perception depends on the rate of change of aroma concentration in the nose, and train our guests to use a quick “scratch and sniff” of the appropriate square to enhance the flavour of their food. Some sandwiches that have lost their flavour in the rain are restored in this way, with the guests eating them while sniffing the tablecloth.
For the children present, we have provided foods made into unusual shapes. Stretched pasta strands have been used to form the spokes of a wheel, which the children heat on one side with a candle. The wheels surprisingly rotate, not because of convection currents but because, as I attempt to explain, the rubbery pasta on the heated side shrinks as the extended starch molecules attempt to return to their entropically favourable random coil configurations. The wheels keep the children amused and introduce them to a scientific principle at the same time.
As darkness closes in, we produce food decorated with leaves from mustard plants that have had a gene from a phosphorescent jellyfish incorporated so that they glow with a soft green aura. The plants have been developed by University of Florida professor Rob Ferl to report on conditions for food growth on Mars, with the leaves glowing more vigorously as the conditions become harder. Here on Earth, Wendy has arranged the leaves to label the different foods on each plate, enabling guests to identify them in the gathering gloom.
The grand finale, a real eye-catcher, is jelly flambé, my own invention, formed from full-strength vodka or other strong alcoholic drink. At home I set these jellies on fire by pouring a little flaming brandy over them, but here I use a propane torch. The jelly melts if left burning for too long, but this is overcome by forming the jelly in layers, with the layer second from the top being a standard water-based jelly that acts as a fire extinguisher before things get out of hand. As heads turn at neighbouring tables, I turn to Wendy and say “Let’s see them beat that!”
© This article is copyright Len Fisher. Please email Len Fisher to seek permission to reproduce part or all of the above article.