When associate food editor Rachel Gurjar was in the process of developing her Chile-Vinegar-Marinated Cornish Game Hens for BA’s November issue, she kept running into a problem. After many passes at testing the recipe, she could not get the potatoes, marinated in a bracing vinegar sauce and roasted beneath the chicken, to soften.
She tried cutting the potatoes down from two-inch to one-inch pieces. She cooked them separately from the Cornish hens. She gave the potatoes more time in the oven, letting them bake longer after taking out the hens to rest. Still, no luck—the potatoes remained stubbornly firm no matter how long they lingered in the oven.
“That’s when I realized something’s up,” said Gurjar. “It’s not the potatoes, it’s not the cooking temperature—something else is going on here.” After plenty of internet sleuthing and some trial and error, Gurjar figured it out. It was the vinegar.
Some food science: Potatoes (like many other starchy plants) contain hemicellulose, a carbohydrate that provides structure to the tuber. It also readily breaks down when boiled in water, lending to the creamy texture we know and love. Acid, such as the vinegar in Gurjar’s recipe, can throw a wrench in the plan.
“Hemicelluloses are not very soluble in acid conditions,” writes Harold McGee in On Food and Cooking: The Science and Lore of the Kitchen. “This means that fruits and vegetables cooked in an acid liquid—a tomato sauce for example, or other fruit juices and purées—may remain firm during hours of cooking, while in neutral boiling water, neither acid nor alkaline, the same vegetables soften in 10 or 15 minutes.”
After determining that cooking the potatoes directly in the vinegar was the culprit, plus some excursions down a Reddit rabbit hole, Gurjar’s solution for her recipe was simple: Give the potatoes a speedy boil in plain, salted water first, before slathering them in the tangy chile sauce to roast with the chicken. The end result is potatoes with plush, creamy interiors; golden, roasted, crackly exterior; and that punchy, bright, Goan recheado masala–inspired sauce to round it all out.
Next time you find your spuds refusing to soften, whether simmered with tomatoes, cooked with a lemon marinade, or stewed in a vinegary sauce—it’s probably not the potatoes at fault. Give them a par-boil in good old salted water first, before you dress them in that tart, mouth-puckering acid.