Word of mouth; specialist chilli supplier Dodie Miller. Photograph by Claudia Janke
From a cold lock-up in a mews near Portobello Road market in west London, Dodie Miller sends out heat, rated on a scale of one to 10. That's chilli heat, in the form of dried capsicums which she imports, stores, bags and posts around the country dashingly packed for her Cool Chile Co. Miller spells chilli the US way, for although she has spent most of her life here, she remembers New Mexico from childhood where even at breakfast the omelettes had green peppers in them.

Working as a waitress in the early Eighties, she witnessed the emergence of new British cooking as it pounced on ingredients from around the world. She recalled her childhood holidays and thought, she tells me with barely a trace of an American accent, "Blimey, there's all these chillis over there that no one's using." From there Miller became "a chilli boffin", discovering - in a way that seldom happens in a shrinking world where everything edible has been exploited and packaged - "a whole new spice box".

In 1994 she bought a shipment of chillis from the States, but since then she's found a reliable supplier in Mexico. As well as drying them, he sterilises them, otherwise they can harbour, and be eaten by, moths - the same ones that eat your jumpers.

Botanically, chillis are complex and cross-polinate very easily, producing endless variations. "Although there are a huge number of chillis out there," says Miller, "there are 20 varieties that are distinct enough to use in different ways." And it is these, whole and dried, which she distributes.

Recently she's started supplying some of her range to Sainsbury's, although it remains to be seen whether its customers are ready for ancho powder (from dried poblano chillis), caribe (crushed guajillos), as well as yellow and blue masa harina cornflour, which is used in the making of tortillas, tamales (a minced meat and cornflour mixture cooked in corn husks) and bread.

Sainsbury's also sells her habaneros, the hottest of the chillis but, as far as Miller is concerned, the least interesting. Mail-order customers rarely request them a second time. "If you go for the burn you're missing the point. I don't go in for the eat-hot-shit end of it."

Her chillis are about flavour first, then heat - the drying process condenses the sugars and flavours, making for complexity and subtlety. Most popular with Miller's customers are the anchos, big and sweet and fruity, and chipotle, the smoked jalapeno. A personal favourite is guajillo, with a fresh, tangy, piney, almost sweet heat, and which makes bright red sauces for pizzas and pasta.

Miller's service includes sending out detailed notes on how to seed, soak, toast and grind, and puree and freeze the different sorts of chilli, and she looks out for recipes which use them. These come on the Cool Chile Co's distinctive yellow paper. "I like to cook, I like food and I like designing all the packaging," she says, explaining the care and knowledge she puts into selling and the enjoyment she gets from having more contact with her customers - especially her core of "hard nuts".

On Saturdays she has a stall at Portobello Road market where in summer she also sells salsas and tortillas. But because the chillis are not perishable and not heavy - a little goes a long way, too - they're ideal for mail order. Hence Miller has as many customers in Scotland and Ireland as in London and the south-east.

What surprises Miller is how few chefs experiment with her wares. Most restaurants in this country where the word chilli features at all are Tex-Mex joints, churning out nachos and chilli con carne simply to soak up lager and margaritas. Real Mexican cooking is highly evolved and labour- intensive. With the right chillis so easily available, there's now no excuse not to try more

Cool Chile Co, PO Box 5702, London W11 2GS (telephone, 0870 902 1145, fax, 0870 056 2288)