Tuesday, 18 October 2011

Hot off the press

How on earth did people come to decide that chilli peppers were a good addition to a meal? Here is a plant that comes from a family (the Solanaceae) which are often poisonous, and whose fruits contain a compound that specifically attacks mammalian pain receptors, causing a severe burning sensation. Nonetheless, about 8 or 9 thousand years ago, someone in Central or South America tried one and thought ”Hey, that’s great! I will put it in all my food!”

I ask the question because a few weeks ago Bristol had a festival of Chilli and Chocolate (heavy on the chilli) As part of the 175th anniversary celebrations the gardeners grew 175 different varieties, in all sizes, colours, and fieriness. Until I saw them all together I did not realise there were so many, but they could have grown more. The various plants were put on a tent on the lawn, and visitors were very interested. At the end the plants on show, plus some spares, were sold off to raise funds.

The multitude of chillis are actually derived from five different species of Capsicum, and this is reflected in their growth habit, fruit shape, and the concentration of Capsaicin (the active compound that gives “heat” to a pepper. The heat of a chilli is measured in Scoville units, which are calculated by measuring how dilute an extract of the fruit must be before the capsaicin is undetectable. The rating of various peppers varies from 0 for bell peppers, up to the current world record holder (actually grown in England!), the Dorset Naga, one of which was measured with a rating of 1,382,118 units, which is hotter than pepper spray.

The wild plants that gave rise to the cultivated peppers of today are basically weedy early successional shrubs of forest clearings. An individual plant can last perhaps five years if it does not fall prey to pests or diseases, and chillies can be kept overwinter in pots in a greenhouse or a windowsill if the weather is to cold outside.

The chilli became a worldwide item of diet as a result of Spanish and Portuguese monks spreading them around their countries empires once they found they could be used as a substitute for black pepper, which comes from an entirely different plant and was so expensive and hard to obtain that it was used a substitute currency – as the term “peppercorn rent” still shows. It was the search for pepper and other extremely valuable spices that drove early European explorers in the first place, so one could frame an entire history of the world around the accidental (by Europeans) discovery of the chilli pepper.

In Britain, chillis must be grown under glass to produce a good crop, although they will survive outside in the summer. In warmer climates they can be grown as ornamental as well as food crops – one visitor we had from Australia had planted chilli bushes along the driveway of her house.

The five species of chilli can be recognised by the shape of the fruits and the growth habit of the plant.

Capsicum annuum (which despite its name is a perennial) – Bell peppers, Sweet peppers, Jalapenos and similar.

C.annuum flower
The plants grow to 60cm tall and are densely branched. Fruits are large, usually red or yellow, and the flowers are off-white (sometimes tinged with purple). Some are grown for ornamental reasons, but the fruits of these are still edible.

C.frutescens – Birds Eye, Piri-piri, and Tabasco.

C.frutescens flower
These are usually much hotter than C.annuum, and the fruits are much smaller. The flowers are greenish white and the plants are usually shorter and more bushy.

C.chinense – Habanero, Scotch Bonnet, and the famous Naga peppers.

Dorset Naga
These are mostly extremely hot peppers, with a bushy growth habit. The Dorset Naga is a selected variety of plants originally grown in Bangladesh. At the exhibition at the zoo, I tried a 2mm cube of it and could still taste the heat ten minutes later. If you eat chillis regularly you become desensitized, so it does not taste quite so hot to someone used to Indian or Mexican cuisine, but even so it packs quite a punch. The flowers are usually yellowish and the plant can grow to over 1m.

C.pubescens – Rocoto or tree chilli.

C.pubescens flower
C.pubescens fruit
The specific name refers to the distinctive hairy leaves. Not often seen outside South America, they can grow to 4m tall, and sometimes have a climbing growth habit. They are also much longer lived, and can last 15 years.

C.baccatum – Amarillo or Aji peppers.

C.baccatum fruits
These are especially popular in Peruvian and Bolivian cooking, and have unusually shaped fruits. The plant is fairly large, and the fruits are not especially hot.

The key to growing chillis in the UK is to start the plants from seed early. They need a long growing season as the fruit ripens fairly late in the year. Any standard potting compost will do to grow them, but the flowers may require hand pollination with a brush if they are being grown inside.

(images from wikipedia)

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