Timeless Thyme Throughout the ages, thyme has had a beautifully positive image. Its name, which comes from the Greek word thymon, has been given various meanings, but “courage” and “sacrifice” appear most frequently. For example, the ancient Greeks could pay no higher compliment than to say, “He smelled of thyme.” For the Romans, thyme was a remedy for melancholy and an agent of courage and strength when infused in bath water. During the Middle Ages, ladies commonly embroidered a sprig of thyme into the scarves they gave to gallant knights to symbolize courage.
What is thyme?
There are as many as 100 thyme varieties, which differ in appearance, aroma and flavor. It is possible, for example, to purchase thyme with flavors and fragrances ranging from lemon or pepper to mint, pine, licorice, caraway or nutmeg. The spice trade, however, deals almost entirely with the leaves of Thymus vulgaris L., known as sweet or garden thyme, a small perennial of the mint family.
T. vulgaris leaves yield from 0.8% to 2.0% volatile oil. Their grayish-green color differs in intensity according to origin. The plant, which grows to about 18-in. tall, produces small rosy- to lavender-colored flowers. Thyme is produced domestically and grown in a number of other countries, including Jordan, Israel, Columbia, Morocco and France.
The major types of thyme
French. At one time, France accounted for approximately 30% to 50% of the U.S. thyme supply; but in recent years, production has declined. Despite this, the French product continues to command high prices for its oil content, color and cleanliness. Its leaf particles average larger than those from other sources and are somewhat greener in color. Most French thyme is still a product of wild plants, but some of its production today comes from cultivation. The Provence region produces a high-quality product; however, very little “true” Provence thyme is seen in the U.S. market. Mountain-grown Provence thyme, from wild plants, has an extremely high oil content, and consequently a strong, but pleasant, flavor.
Spanish. Spain harvests three seasonal T. vulgaris varieties: winter (February to March); gray (April to May); and red (May to June). These varietal names, however, are not descriptive; all three types look very similar. The red type has the highest oil content, and is used primarily for distillation. The gray is favored for the spice trade, because it is handled and cleaned carefully, and also has a high oil level. Winter Spanish thyme — with the lowest oil-content percentage and less attractive leaves — is the least expensive product. These distinctions are made primarily within the spice trade. The food company buyer is more apt to find terms such as fair average quality (FAQ) — a term referring mostly to cleanliness — or “Spanish Fancy.”
Domestic. California produces much of the domestic thyme product available. Most of this product is T. vulgaris, but a small amount of T. citriodorous (lemon thyme) is produced in the Golden State as well — mostly for use in herbal teas. All of the California-grown thyme is cultivated, not wild, and yield is approximately three crops per year. As with many other domestic herbs, American thyme is machine-dried and cleaned, and selected for rich color, as well as flavor.
The flowering tops of thyme plants are used to produce both essential oil and oleoresin extractives. As with other aromatic herbs, volatile oil is the most important extractive. Spanish red-thyme oil, a primary volatile oil source, is marketed as red thyme oil. The product marketed as white thyme oil, a redistillation of the red oil rather than the product of another plant, generally has a smoother flavor than the red oil.
Essential thyme oil, located in small oil glands on leaf surfaces, can be extracted by steam distillation. Yield and quality vary according to the genetic makeup of the plant material, crop maturity, oat harvest and distillation practice. Thyme oleoresin, with both volatile and non-volatile components, is a very viscous material that normally is standardized with a food-grade solvent before use. The oleoresin often is added to liquid or dry soluble carriers for seasoning applications.
Buying and using thyme
The best purchasing method for thyme is to notify a spice supplier of your product needs (such as the relative importance of color, aroma, flavor, etc.) and then have them recommend the thyme product best suited to the purpose and budget.
Thymol, the active ingredient in thyme oil, is a carminative, anti-spasmodic and counterirritant. The pharmaceutical industry currently uses a synthetic thymol, but before its development, thyme oil was used in cough drops, antiseptic mouthwashes, liniments and antifungal preparations. The food industry uses thyme as a supporting flavor and fragrance in many different savory formulations — from salad dressings to stuffing mixes, poultry seasonings, soups, sauces, gravies, condiments, entrées, herbed breads, snacks, sausages, vegetables and liqueurs. Thyme accompanies bay leaves and parsley in the “herb bouquet” mixture, and seasons Mediterranean cooking in blends with savory, oregano, rosemary and marjoram. Of all its many applications, Manhattan-style clam chowder probably comes closest to giving thyme a starring role.
Thyme and its extractives should be stored under cool, dark, dry conditions to protect against fragrance and flavor loss. As with any highly aromatic herb, thyme leaves should be further protected against flavor loss by always making sure that the container is tightly closed after each use. Under good storage conditions, thyme leaf should retain its flavor qualities and strength long enough to meet all normal food-manufacturing requirements.
Spice Rack is based on the American Spice Trade Association's What You Should Know informational series on spices. For more information, call 202/367-1127, or visit www.astaspice.org.
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