Vanilla: The 'Chanel No 5' of flavours
Fresh vanilla is favoured around the world, in all manner of cooking.
"It tastes so ludicrously of itself, it's like a culinary onomatopoeia," says Jeremy Lee, head chef at Quo Vadis in London's Soho.
Vamp it up with vanilla
The taste is from the compound vanillin, which is found in the vanilla bean, a pod which grows inside the flowering vanilla orchid.
"It is the Chanel No. 5 of the flavour business," says taste-matching guru Niki Segnit, author of The Flavour Thesaurus.
But vanilla's popularity now poses a challenge: how to grow enough to keep up with demand?
Just growing vanilla is a long, complicated process.
Lulu Sturdy has a vanilla plantation in Uganda, and is one of around 1,000 neighbouring farms producing Fairtrade vanilla, some of the best you can buy.
In the wild, a vanilla orchid climber "would be growing up a nice fat tree trunk, something it can really hug," she says.
"To stop it growing up into the canopy where you're never going to be able to harvest the beans, you'd drape it over the top of tree, let it hang down, and then when it reaches the ground, you loop it about 6ft through the soil again. The flowers will only appear on the parts where the roots aren't attached to the growing part."
- The Western world's love affair with vanilla began in the 16th Century, when the Spanish were introduced to it during their colonisation of the Americas.
- The Aztec leader Montezuma gave Conquistador Hernando Cortez and his men a bitter frothy chocolate drink flavoured with vanilla after dinner.
- Vanilla arrived in Britain in the early 1700s, and people loved it. But the climate meant it couldn't be grown. Plantations thrived in the French colonies, Mexico and Indonesia.
- But in the mid-1800s Germans found they could create artificial vanilla using extracts from paper pulp, and vanilla essence "took off" in the Victorian period. Fresh vanilla crops lost their value and plantations were almost wiped out. Most of the world's beans are now produced in Madagascar, and are known as a Bourbon kind.
Source: William Sitwell, author of A History of Food in 100 Recipes.
From pollination it takes nine months for the vanilla to ripen, when it starts to split. Pods are easily picked and graded according to their size - they need to be 14 to 20cm (6 to 8ins) - and their colour.
"You cannot get a stronger vanillin bean than one that is left to ripen naturally on the vine, till it starts splitting, and pick it then at the right time," says Ms Sturdy.
After they are picked, pods are blanched in hot water for three minutes, wrapped up on a blanket, and put in a curing box.
Forty-eight hours later, the pods are exposed to the sun for two hours, then returned to the sweating boxes. This happens once a day for two to three months, until they are ready.
"So much care and love goes through the whole process," Ms Sturdy says.
Vanilla is also expensive.
This "incredibly labour intensive" production process is the reason vanilla costs so much.
It is the second-most expensive spice after saffron, with pods selling for £10,000 a tonne. Pods can cost £1.50-£2.50 each for the average shopper, and as much as £5 depending on the quality.
Other costs are factored in too.
"There's one type of bee in Uganda that will pollinate vanilla, but they are too few and far between to pollinate all the vanilla flowers," she explains.
"Each and every vanilla bean you are eating has been hand pollinated by a pair of human hands," says Ms Sturdy.
While pollination is labour intensive, so too is the traditional method of propagation, through stem cuttings.
That is because the supply of mother plants is limited, and they can't themselves produce many vanilla pods.
Scientists are now studying how best to propagate fresh vanilla, as demand for the flavour grows.
Dr Chin Chiew Foan from the University of Nottingham's Malaysian Campus School of Biosciences is part of a team working to create new ways to clone the most common cultivated vanilla orchid, Vanilla planifolia, without creating lesser quality, mutated "sub-clones" that don't have such good yields.
She says: "Due to a high demand for natural vanillin, there is a need to develop more vanilla plantations."
That means supplying more quality plantlets through propagation, which is struggling to keep up using conventional methods.
"We are finding ways to mass produce quality vanilla plantlets through plant tissue culture."
However, when tissue from plantlets is regrown in culture, mutations can creep in, especially over several generations.
That can help plant breeders, who look for new variations. But it can be a disadvantage if breeders want quality clones with similar traits to the parent plant.
Today's science is a long way from the discovery of vanilla, which was made by the Aztecs and shared with the Western world by the Spanish in the 1600s.
William Sitwell, an author of A History of Food in 100 Recipes, says the ingredients the Spanish found in the Americas, such as turkey, chilli, tomatoes, cocoa and vanilla, changed the food world forever.
In the UK, he says, "vanilla essence took off, during the Victorian period.. when they loved tinned food".
"The artificial creation of essence very nearly destroyed fresh vanilla crops".
But today plantations are being replanted, as cooks around the world now demand the best beans.
Camilla Bond, head of marketing at The Bart Ingredients Company in Bristol, says "we're looking at length, moisture and colour" when selecting the best beans.
"We want them to be a uniform dark choc brown to reddish colour, they'll have no stains on them, they'll be creased as they be dried and rolled, and have an aged look after they've been cured off.
"We'll expect our vanilla to be about 15-17cm (6-7 ins) long, with a minimum width of 5mm (0.2ins).
"They'll be whole, sound and supple, you don't want them brittle. And (to be) slightly stick, " she explains.
Not all vanilla tastes the same.
"Some have an anise flavour, you might see some caramel, there's obviously some floralness, fruitiness, prune, some types that have much more of a chocolate character. You might find honey notes, jasmine, hay or tea, smokiness, woodiness, resin... there's a whole lexicon of vanilla," says Niki Segnit.
Which is best?
Vanilla pods: Contain seeds from the vanilla orchid plant, which are scraped out and used in cooking. Real vanilla is expensive due to hand pollination of flowers and the lengthy curing process to turn green seed pods into wrinkly, dark-brown pods.
Vanilla essence: An imitation taste which can be made from wood pulp, or a petrochemical reaction, even clove oil. Pure vanillin crystals which appear on pods are the compound upon which the taste of essence is based.
Vanilla extract: Derived from the vanilla pod and produced by steeping in alcohol and water. Vanilla extract has the true flavour and aroma of vanilla pods rather than essence.
And a pod's flavour can become visibly more intense.
"Sometimes you can get a natural frosted look to them, these little white specks, which is a naturally forming crystal... the vanillin which naturally forms on it," says Ms Bond.
Once the seeds of such pods have been used in recipes, empty pods can be used to flavour other ingredients.
"The thing I love doing the most with vanilla is making a bowl of vanilla sugar," Mr Lee says.
"It can do a lot of work just on its own, or combines fabulously with different fruit, or other spices too, and is increasingly being used of course with shellfish and fish," says Ms Segnit.
So can you ever go wrong with vanilla?
"Like all the great spices it has this curious problem that too much, is way too much," says Mr Lee.
So be careful with those potent pods.