ACID DAZE

The Sydney Morning Herald Magazine, June 5, 1999, page 54

Citrus fruits are the revolutionaries of the food world because, in the culinary process, they activate change. Their versatility plays an integral role the skin, seeds, juice, flesh, blossoms and leaves all contribute to the chemistry of food. The lemon, cumquat, orange (navel, valencia, seville and blood), clementine, mandarin, grapefruit (ruby and yellow), pomelo, lime (Tahitian and Kaffir) and tangelo all play a major role as flavour enhancers. And they don't come out of a bottle! As fresh ingredients, they have a long shelf life, but are best freshly picked and ripe, and used at their peak.

Some have specific, short seasons and must be pounced on to take best advantage. The gorgeous blood orange appears briefly at the beginning of spring, as does the bitter seville (its juice is perfect for cooking and the whole fruit for marmalade), mandarin and clementine in early autumn, cumquat and rangelo in winter and pomelo in autumn and spring. Navels are best in winter and the valencia shines through the warmer months.

For a moist and fragrant cake, try the orange almond cake (tarta de Naranja) in Claudia Roden's Mediterranean Cookery. The oranges from the tropical climates of China, India and South-East Asia are sweeter, with a finer skin than other varieties. The dried peel of the orange is essential in Chinese cooking, as it contains the most intense flavour and essential oils. It also combines brilliantly with star?anise.

As well as being a rich source of vitamin C, lemons and limes are used raw or preserved in many cuisines to balance the richness of food, to preserve or to add a lift to a dish. Limes come from more tropical climates and are an essential ingredient for Asian-style flavours in food, to give the right sour/acid balance and for depth and intensity of flavour. Kaffir limes are essentially used for their zest.

In North Africa, lemons and limes are preserved in salt and their own juice to give a pickled taste to foods they are cooked with. Their colour and firm shape are retained in the liquid, but their potent acidity is changed, as is their taste. They are used with aromatic spices and herbs to provide an antidote to the richness of meat and the oiliness of fish and olives.

The culinary versatility of the lemon is renowned. "A lemon is the ideal household implement, an
honourable standard against which all patented inventions might be measured," Canadian writer Margaret Visser notes. "A modem kitchen without a lemon in it is gravely ill-equipped."

For a different taste sensation, try to get your hands on some Limoncello, an Italian aperitif. Made in Adelaide under the Ambra label, it tastes perfect straight up or luscious mixed with tonic over ice. It's also an interesting ingredient to introduce into desserts that call for a citrus taste. The clementine, of Algerian and Spanish origin and little known in Australia until recently, is being commercially grown in the Riverland in conjunction with the Spanish citrus company Bagii of Castell6n. It has an appearance and taste similar to the mandarin, but is sweeter, slightly larger and without the annoying seeds. (Try a candied whole clementine, a great addition of flavour and texture to a citrus dessert, from Simon Johnson outlets in Sydney and Melbourne.) Curuquats are of Chinese origin and are fantastic to cook with. Their small size makes them laborious to use because it is essential to remove all seeds, but the resulting intensity of flavour cannot be matched.

In the following simple recipe for a sweet curd, any citrus juice can be substituted for the lemon juice. The acidity works to balance the fat richness of the eggs and butter creating a perfect harmony. A delectable basic to always have on hand, serve it in a sweet baked tart shell, spread between layers of sponge, with butter shortbreads, or use in the same way as butter on toasted brioche or sourdough, in a classic lemon meringue pie or to flavour petits fours.

LEMON CURD (makes 350 ml)
5 large egg yolks
100 g castor sugar
110 ml lemon juice, strained
125 g cold, unsalted butter, cut into cubes

Whisk yolks and sugar in a bowl until light and fluffy. Add lemon juice, then stand the bowl over a bain-marie or a pan half-full of simmering water and cook until thick, stirring constantly.

Add butter piece by piece, allowing each piece to be incorporated before stirring in the next. The mixture should have become thicker by the time the last piece of butter has been added.

Remove bowl from the heat and stand over ice to cool. Store the curd in a sealed container in the fridge.