The aphrodisiac idea is not a new one. In the 16th and 17th centuries, physicians credited vanilla with medicinal properties and used it as a stimulant, stomachic, aphrodisiac and antidote to poison, and it appeared in the US Pharmacopeia until 1910. Perfumiers, from Chanel and Guerlain to, more recently, Thierry Mugler, have recognised vanilla's captivating warmth. Vanilla was an instant hit with Cortez whose conquistadors first tasted it, mixed with cocoa and honey, in the Aztecs' version of hot chocolate. Madagascar is now the world's biggest producer of vanilla, and if you have ever wondered why a couple of vanilla pods will set you back pounds 1.95, even in a sensible shop like Sainsbury's, the reason is that, to this day, vanilla depends on hand-pollination.
Rayner has been making flavourings and essences - including more than a hundred versions of vanilla - in the shadow of London's North Middlesex Hospital since the 1950s. One wintry afternoon recently in the factory sample room, which smelt disconcertingly of Opal Fruits and burnt toast, chemist Peter Tiwari pondered with me the ranks of square plastic litre bottles ranged alphabetically (apricot to violet) on floor-to-ceiling shelves. He picked Vanilla 26N302, unscrewed the cap, gave it a sniff, then passed it to me. I sniffed. Alcohol, and... was that really vanilla? He offered me other bottles. Different essences and extracts registered as physical sensations on different parts of my olfactory equipment. Feel had as much to do with it as smell.
Other sniffs offered vanilla with overtones of caramel, nuts, alcohol and malt. What were so many different vanillas destined to flavour? Ice- cream has traditionally been the biggest user of vanilla -and that's still the case with premium ice-creams for the adult market demanding costly natural extract of real vanilla pods. Other big users are manufacturers of chocolate, fudge and toffee, bakers of cakes and biscuits, margarine makers, even pop producers - remember cream soda? Vanilla milkshakes are big at the moment; vanilla-flavoured coffee, no novelty in America, is beginning to catch on here.
Price constraints and usage are the reasons for the size of Rayner's range. Vanilla extract is, as the name implies, extracted from vanilla beans and it costs up to 30 times the price of its lab-made mimics. Chemically synthesised vanillin is stronger and cheaper. This is called nature-identical vanillin and it lacks some of the subtle vegetable scent notes produced when extracting vanillin from pods. Then there is ethylvanillin, synthetic vanilla flavouring, which is cheapest and strongest and goes into wham- bam vanilla essence and dozens of different flavouring blends sold to food manufacturers.
Even the fussiest boutique ice-cream maker eschews vanilla pods in favour of flavouring that comes in bottles, and he or she may want a vanilla to call his own. Bespoke flavourings account for a fair number of Rayner's 100-plus vanillas.
At home, I use whole vanilla pods, long, slender and black as liquorice, to flavour ices, baking and puddings. There are two or three pods in a bottle of cognac (a splash for crepe batter, chocolate mousse, any ice- cream) and a selection of part-worn pods in a big jar of caster sugar for custards or cakes.
Real vanilla extract is much easier to find than it used to be and comes in bigger bottles than the stronger synthetic essence. Any recipe specifying a few drops of vanilla is likely to mean essence, and you will need more extract to get the same level of flavouring. It is harder to overdo things with the real stuff. Go softly, go subtly.
Although usually used in sweet dishes, vanilla is occasionally used with great success in savoury recipes. When saucing sweet-tasting fish or shellfish, simply grilled or baked, the scent of vanilla in a classic beurre blanc is tantalisingly different.
Real, old-fashioned vanilla ice-cream made with egg custard is the best "plain" ice-cream of all.
Vanilla ice-cream, serves six
1 vanilla pod or vanilla extract
700ml (11/4 pints) whole fresh milk
6 egg yolks
275g (10oz) caster sugar
A pinch of salt
Split the vanilla pod lengthwise and put it into a heavy saucepan with the milk. Heat to near boiling, leave to infuse for 30 minutes, then remove the vanilla. Whisk together the egg yolks, sugar and salt until the mixture is very pale and falls back leaving a trail when the whisk is lifted.
Whisk in the milk and return the mixture to the pan. Cook it on a low heat, stirring constantly, until the custard is thick enough to coat the back of a wooden spoon. If you are patient, or afraid of curdling the custard, cook it in the top of a double-boiler. If you are fearless, cook it on a medium heat - it will be ready exactly when the froth disappears.
Cool the custard and, if you are using vanilla extract, add it now. Freeze it in a sorbetiere. Alternatively, still-freeze it, vigorously whisking the partially frozen ice once or twice during freezing.