The Food Lab: Better Home Cooking Through Science

by J. Kenji López-Alt

ITEM HOW LONG WILL IT KEEP? Baking Powder 6 months to a year, depending on humidity; to test for activity, place a teaspoon in a bowl and add a teaspoon of water: it should bubble and fizz vigorously. Baking Soda 8 months to a year Cornstarch Indefinitely Dutch-Process Cocoa 1 to 2 years Flour, all-purpose Transferred to a sealed container up to a year Flour, bread Transferred to a sealed container up to a year Gelatin, powdered Indefinitely Sugar, brown In an airtight plastic bag, 3 to 4 months optimally—after that, it may harden; hard brown sugar can be restored by briefly microwaving. Sugar, granulated Transferred to a sealed container, indefinitely Vanilla Extract 1 to 2 years Yeast, instant (rapid-rise) If possible, purchase in bulk and transfer to a sealed container; individual packets are harder to use and far more expensive. Keeps indefinitely in the freezer; if stored at room temperature or in the fridge, it will need to be proofed occasionally: add 2 tablespoons warm water and 1 teaspoon sugar to ½ teaspoon yeast and let sit for 10 minutes—it should produce foam. If not, replace.