Ground oregano is made by drying the leaves of the oregano herb and grinding them into a powder. Oregano is used for a variety of culinary purposes, and the ground variety is particularly popular as a dry rubbing ingredient for meat that is being prepared for barbecuing. Bottles of ground oregano can be purchased, but storage containers and an herb mill are needed to produce and store it.
Oregano is generally grown in warm climates and may also be referred to as wild marjoram. The leaves, which are often used for cooking, are generally about half an inch (1.3 cm) to just over 1.5 inches (about 4 cm) long. The leaves are harvested and dried, which involves bundling and then hanging them upside down in a warm area or in a room which allows air flow. The leaves may take a week or longer to become completely dry, after which, they can be ground into a powder.
Cooks who are preparing a dish that calls for this kind of oregano should not confuse ground oregano with dried oregano. Dried oregano generally refers to oregano leaves that have been crumbled or left relatively intact but not ground into a powder. Ground oregano is frequently used, either by itself or as part of a mixture of other herbs or spices, as a dry rub for meat that is going to be grilled or barbecued. Applying a dry rub involves sprinkling the ground oregano or the mixture onto the meat and rubbing it into the meat before cooking.
Making ground oregano requires an herb mill and one or more airtight containers. The herb mill allows the user to grind the dried oregano leaves into the consistency that he or she prefers, which can be relatively coarse or very fine. Containers used to store the ground oregano should be completely airtight to prevent contamination and to preserve the flavor of the herb. The container should be stored in a dry and cool place to keep the ground oregano fresh and flavorful for as long as possible, which can be up to a year or more.