1 cup = 92 grams
1 cup sifted = 75 grams
Natural Unsweetened or Nonalkalized Cocoa:
1 cup = 82 grams
Substitution for 3 tablespoons (18 grams) Dutch-processed cocoa: 3 tablespoons (18 grams) natural cocoa powder plus pinch (1/8 teaspoon) baking soda
Substitution for 3 tablespoons (18 grams) natural cocoa: 3 tablespoons (18 grams) Dutch-processed cocoa plus 1/8 teaspoon cream of tartar or 1/8 teaspoon lemon juice or vinegar
Note: Due to the differences between natural and Dutch-processed cocoa powders, do not substitute one for the other in recipes.
Note: Do not confuse unsweetened natural and Dutch-processed cocoa powder with sweetened cocoa drink mixes. They are not the same thing.
Cocoa powder is made when chocolate liquor is pressed to remove three quarters of its cocoa butter. The remaining cocoa solids are processed to make fine unsweetened cocoa powder. There are two types of unsweetened cocoa powder: natural and Dutch-processed.
Dutch-Processed or Alkalized Unsweetened Cocoa Powder is treated with an alkali to neutralize its acids. Because it is neutral and does not react with baking soda, it must be used in recipes calling for baking powder, unless there are other acidic ingredients in sufficient quantities used. It has a reddish-brown color, mild flavor, and is easy to dissolve in liquids. Its delicate flavor makes it ideal in baked goods like European cakes and pastries where its subtle flavor complements other ingredients. Droste, Lindt, Valrhona, Poulain and Pernigotti are some popular brands.
Natural Unsweetened Cocoa Powder tastes very bitter and gives a deep chocolate flavor to baked goods. Its intense flavor makes it well suited for use in brownies, cookies and some chocolate cakes. When natural cocoa (an acid) is used in recipes calling for baking soda (an alkali), it creates a leavening action that causes the batter to rise when placed in the oven. Popular brands are Hershey's, Ghirardelli, and Scharffen Berger.
The role of cocoa powder in cakes:
When used alone in cakes, cocoa powder imparts a full rich chocolate flavor and dark color. Cocoa powder can also be used in recipes with other chocolates (unsweetened or dark) and this combination produces a cake with a more intense chocolate flavor than if the cocoa wasn't present. Most recipes call for sifting the cocoa powder with the flour but to bring out its full flavor it can be combined with a small amount of boiling water. (If you want to try this in a recipe, substitute some of the liquid in the recipe for boiling water.) Often times, you may notice that more butter and leavening agent are used in recipes containing cocoa powder. This is to offset cocoa powder's drying and strengthening affect in cakes. There are two types of unsweetened cocoa powder: natural and Dutch-processed and it is best to use the type specified in the recipe as the leavening agent used is dependent on the type of cocoa powder. Some prefer using Dutch-processed cocoa as a slight bitterness may be tasted in cakes using natural cocoa and baking soda.
To convert a cake recipe that uses bittersweet or semisweet chocolate to one using cocoa: (information taken from Rose Levy Beranbaum's Cake Bible)
Substitute 1 tablespoon plus 1 3/4 teaspoons (9.5 grams) of cocoa, 1 tablespoon plus 1/2 teaspoon (14.5 grams) granulated white sugar, 1 1/2 teaspoons (7 grams) unsalted butter for every ounce (28 grams) of bittersweet or semisweet chocolate. Also, dissolve the cocoa in at least 1/4 cup (60 ml) hot liquid to bring out the cocoa's full flavor.
To convert a cake recipes that uses unsweetened chocolate to one using cocoa: (information taken from Rose Levy Beranbaum's Cake Bible)
Substitute 3 tablespoons (18 grams) cocoa plus 1 tablespoon (14 grams) unsalted butter for every 1 ounce (28 grams) of unsweetened chocolate. Dissolve the cocoa in at least 2 tablespoons of liquid in the recipe to bring out the cocoa's full flavor.