In the quest for a crisp finish to her Chinese doughnuts, Lorna Yee relies on an old culinary standby
WHAT IT IS: Alum powder (crystallized potassium aluminum sulfate) is an astringent white substance commonly used in pickling recipes to retain crispness. You can find it in the spice aisle of grocery stores. It’s also an ingredient in baking powder (responsible for the faintly metallic taste). In recent years, alum powder has become increasingly difficult to find because it is toxic to humans if consumed in large quantities (more than 1 ounce).
HOW I DISCOVERED IT: I had never heard of alum until I started looking for recipes for you tiao—those long Chinese doughnuts typically served with congee. Recipe after recipe called for this new-to-me ingredient, which was essential in creating a crisp crust on this delectable fried treat.
HOW TO USE IT IN THE KITCHEN: Alum powder is often used in vinegar brine for pickles or in homemade (and inedible) modeling clay for kids. My favorite way to use alum is in a light, crispy, yeasty batch of deep-fried you tiao.
WHERE TO FIND IT: You can find alum at myspicesage.com (a 1-ounce package for $1.50) or at Persepolis Specialties in Bellevue (13112 NE 20th St. Suite Ste 300; 425.462.8987).