Garlic is available as fresh, flakes/minced, granulated and powder. However, garlic, in any form is best added late in the cooking process of dishes such as sauces, soups and stews. Heat breaks down and dissipates the essential oil, lessening the flavor and aroma of the dish over time. As for garlic powder, it blends more easily into liquids and is a good choice for sauces and other recipes where flavor, but not texture or bulk, is desired. Use it in tomato-based dishes, dressings, sausage, and spice blends. Or sprinkle it on buttered bread before broiling.
One-half teaspoon garlic powder is roughly equivalent to one clove of garlic.