A small brush used for applying glazes to breads, pastries, cookies, etc., either before or after baking. The best all-purpose size has a width of 1 to 1½ inches. Pastry brushes can be made of nylon bristles, sterilized natural bristles or goose feathers. Natural-bristle brushes are considered best because they're softer and hold more liquid. Goose feathers are excellent for egg glazes because they leave a thin, even coating. The harder nylon bristles will last longer but may melt if accidentally touched to a hot surface. Softer bristles are especially desirable for delicate unbaked pastries where harder bristles might leave unwanted marks.
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.