Don't just drink it, writes Nikki Smith. Coffee's rich, smoky flavours can enhance all manner of dishes.
From delicate, crystalline granitas that cleanse the palate to devilishly dark chocolate truffles that melt voluptuously in the mouth, coffee-infused sweets speak of indulgent, sophisticated pleasure. In days gone by, coffee-drinking was associated with the doubtful morals and rebellious gossip of the London hostelries where it was practised, and a sense of the deliciously wicked still wafts from this dark little bean. With its rich, but faintly bitter, enveloping, smoky twang, this is a very grown-up ingredient.
The coffee bean is essentially a cherry stone, the pip of a rosy little berry that flourishes in steamy, tropical climates. After harvesting, the flesh of the fruit is either dried or soaked, then removed, leaving little green beans to be cleaned and dried. Then comes roasting and, with it, the flavour. Brief exposure to heat caramelises the sugars in the beans, and activates their aromatic compounds, transforming the bland green pips into brown nuggets of intense flavour. Lighter roasts are more delicate but also more acidic, while darker ones are robust, toasty and strong. It's these that work best in cooked dishes where the coffee must hold its own against other powerful flavours - try Java, Blue Mandheling or Malabar varieties.
In cooking, coffee should be treated as a spice. However, the rules are similar to those you would apply when preparing coffee for drinking. Instant can suffice (freeze-dried is best), and is useful for creating an intensely flavoured paste to add to icings, cake batters or cookies. But instant is made from cheap robusta beans rather than the superior arabica, and the manufacturing process banishes all the subtle aromatic elements that you get with freshly ground beans. Ground coffee is better, especially if you're creating something, such as a sauce, in which the coffee flavour, in all its complexity, should dominate.
For the finest flavour, grind the beans just before you want to use them. Charlie Massey, of Hill and Valley Coffee in Aylesbury, explains: "Whereas wine contains in the region of 150 different flavour compounds, coffee has around 900. As soon as beans are roasted, the oils that carry these delicious aromatic elements begin to oxidise. Once they're ground, this happens a lot faster." He says you can detect deterioration 30 minutes or less after grinding. After opening a pack of beans or ground coffee, keep it in an airtight container in a cold, dry place, ideally for no more than a week.
Coffee is the perfect partner to ingredients that mirror its dark, velvety, caramelised qualities: chocolate, nuts, and spices such as vanilla, cardamom, cloves and nutmeg. It also works well with other acidic flavours such as orange and lemon, or even blackcurrant. Then there are the partnerships where coffee is the contrast to something sweet and creamy: custards, ice cream, light mousses or panna cottas - and it's always a winner with spirits, too, from armagnac to vodka.
Heston Blumenthal, the much-lauded, flamboyantly experimental chef at The Fat Duck in Bray, uses coffee to add a nutty, burnt-sugar tone to all kinds of dishes. "The fact that it's roasted is the key thing to remember," he says. "It works with other toasty flavours, from chocolate to caramel and nuts. But keep an open mind." Blumenthal puts coffee in a chocolate cake that also includes blue cheese, and adds it to a tomato compote, which goes with a smoked bacon ice cream. The first combination works, he explains, because there are similar acids in chocolate, cheese and coffee, while the second succeeds because the ingredients combine to give a familiar 'flavour profile' associated with breakfast.
If you want to adapt a recipe by adding coffee, remember that the trick is to do it without adding liquid. Add more than a couple of teaspoons and you could upset the balance of a dish. Try infusing cream or milk with whole beans or ground coffee before straining them out; use a tiny shot of fiercely strong espresso; or make up a paste with a teaspoon of instant coffee and a little water. Coffee for flavouring should be at least twice as strong as coffee you would drink.
A simpler idea is to get your coffee kick with a syrup (see recipe overleaf), perfect for drizzling over creamy mousses, hazelnut meringues or warm-from-the-oven chocolate brownies. But the quickest way to add a coffee boost is just to pour it on, as in the straightforward but delicious Italian afogato: a shot of espresso poured over a scoop of vanilla ice cream. Use the very best coffee and the very best ice cream and you have the ultimate coffee dessert: sweet, yet sophisticated, simple, but utterly scrumptious.