As a female entrepreneur in Vietnam's quickly growing economy, Nguyen Thi Tinh often travels around the country for work and leisure. She never leaves home without a bottle of her own fish sauce, brewed and bottled on the southern island of Phu Quoc. Regional variants of the pungent daily staple, called nuoc mam, leave her cold. 'Yuck! It's terrible. No way would I use it,' she grimaces.
In her cool, shaded warehouse she draws a sample of her latest brew from a tall wooden vat. Showing it to a guest, she inhales deeply and dips her finger into the golden-brown liquid. The verdict? A sharp nose. Nice warm hues. And the taste is, well, sour, salty and unmistakably fishy.
What cognac and champagne are to France, so the fermented fish sauce in Ms Tinh's vats is to Vietnam: a national treasure that shouldn't be produced anywhere else. And everyone agrees that the best fish sauce comes from the island of Phu Quoc. The islanders use only top-grade black anchovies, natural inputs and traditional storage methods to make their sauce, as they have done for a century or more.
Wherever you travel in Vietnam, you're never too far from a bottle of fish sauce. It's a protein-rich mainstay of the cuisine and a constant companion to any savoury dish. Other Southeast Asian countries like Thailand and Cambodia produce their own sauces, but nobody consumes as much as the Vietnamese.
'Every morsel that people put in their mouths is either cooked in fish sauce or dipped in it,' says Ashok Mittal, vice-president of Unilever Vietnam's food division, which sells Knorr-branded fish sauce from Phu Quoc.
Ms Tinh, 50, is a third-generation producer and president of Phu Quoc's fish-sauce association. Of six brothers and sisters, she was the one who decided to take over the family business. Since the economic reforms of the 1980s that opened up new markets for private businesses in Vietnam, she has added new capacity and upgraded her operation.