Both chocolate and cocoa powder come from cocoa beans that grow in pods on the tropical Theobroma cacao tree, which is found in Southeast Asia, Africa, Hawaii, Brazil and other South American countries. Once cocoa beans are fermented, dried, roasted and cracked, the nibs are ground to extract about 75 percent of the cocoa butter, leaving a dark brown paste called chocolate liquor. After drying again, the hardened mass is ground into the powder known as unsweetened cocoa. The richer, darker Dutch cocoa has undergone a treatment (known as the Dutch process) whereby it's treated with an alkali, which helps neutralize cocoa's natural acidity. Cocoa powder is sold plain or mixed with other ingredients such as milk powder and sugar, which creates an instant cocoa mix. Cocoa mixes should not be substituted for cocoa powder in recipes. Store cocoa powder airtight in a cool, dark place for up to two years.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.