When people learn that I’ve lived in Southeast Asia for more than a decade they often remark, “So you’ve acclimated to the climate by now.” How I wish it were so. Growing up in America I despised the Midwest’s sticky, sweltering summers. Now, as a tall Western woman living in consistently hot and humid Malaysia, the only thing I’ve become accustomed to is always being the biggest, sweatiest person in a room.
Yet I haven’t stopped searching for relief from the heat. I’ve most often found it not in an air-conditioned shopping mall but at the elbow of any hawker dishing up something salty and tart. On especially steamy days in Penang, no noodle soup cools and resuscitates me like asam laksa, with its salty shrimp-paste broth soured with tamarind and asam keping,the dried slices of a hard green fruit. In Bangkok som tam (ordered “phet-phet-priaow-priaow,” very spicy and sour) does the trick, even though the chilies that I adore leave my mouth aflame. And if I find myself in northern Laos during the scorching lead-up to summer rains I seek out kao laeng fuen,jellied rice or wheat-flour cubes dabbed with chili-bean paste in a thin broth tart from tamarind or cherry tomatoes.
It’s no surprise that when temperatures rise a dose of saltiness revives, since our bodies lose salt with every drop of sweat. But the connection between sourness and the feeling of well-being it engenders on a hot day is less obvious. According to Australian physician Gerry Bodeker, a specialist in Asian traditional medicines who teaches at Columbia and Oxford Universities, modern medicine and traditional science have nothing to say about the relationship of sour flavors and comfort on a hot day. But Ayurvedic and Chinese medical traditions tell us that “sour tastes can be calming, in small doses,” he says. This is especially true for limes and lemons, to which Ayurvedic doctors assign a “special quality of creating a cooling effect.”
I interpret Dr. Bodeker’s comments to mean that my Southeast Asia-born predilection for salty-sourness isn’t all in my head. Surely it’s no coincidence that every Southeast Asian cuisine highlights tart flavors in everything from soups (sinigang in the Philippines, tom yam in Thailand, asam in Indonesia) to beverages (when it comes to refreshing, few drinks can match the salted plum-soured fresh nutmeg juice served on the Malaysian island of Penang).
In Hanoi, sour-power worship peaks in summer with the appearance of a small round tree-fruit known as qua sau. Its mottled green rind is peeled and then boiled to produce a pulpy liquid for souring canh, or broth. It’s also a favorite addition to bun oc — rice noodles with paddy snails, starchy green bananas and tofu in a pork-tomato broth – which diners ladle on to taste from communal bowls fitted with big spoons.
Qua sau’s special tartness knows no middle ground, says the founder of Hanoi Cooking Centre and author of the new book “Real Vietnamese Cooking” Tracey Lister: “It’s not a case of less is more. More is definitely more.”
Robyn writes about food and travel. She’s lived in Hong Kong, Shanghai, Bangkok, Ho Chi Minh City and Kuala Lumpur. Two years ago she moved to Penang — for the hawker food, of course. Follow her on Twitter @EatingAsia