Lemon myrtle is a citrus-fragranced spice that is native to coastal regions of Australia. It has been described as “more lemon than lemon”. Lemon myrtle has been growing wild in the coastal areas of New South Wales, Victoria and South Australia for many thousands of years. When lemon myrtle was identified and classified, the botanical name Backhousia, was given to this species after a Yorkshire nurseryman, james Backhouse. Lemon myrtle trees are now grown in South Africa, the southern United States and southern Europe and in more recent times, propagation with a view to extracting the essential oil has taken place in China, Indonesia and Thailand.
The lemon myrtle tree is usually grown to around 26 ft. (8 m) tall but can occasionally attain a height of over 60 feet (20 meters). The fragrant leaves, which are 2 to 5 inches (5 to 12 centimeters) long, are dark green, glossy, and lanceolate, or lance-shaped, looking similar to bay leaves. The small, cream-colored flowers of the lemon myrtle grow in clusters at branch tips throughout the summer season. Both the flowers and fruits may be eaten as well as the leaves.
The aroma of lemon myrtle is similar to a blend of lemon verbena, lemongrass and kaffir lime with a slight eucalyptus background. The flavor is distinctly lemony and tangy, with distinct lime zest notes and a pleasantly lingering, slightly numbing camphor aftertaste. Powdered lemon myrtle leaf is coarse, pale green and when fresh releases all of these aroma and taste attributes.
Purchasing and Storage
Fresh lemon myrtle leaves can sometimes be bought from specialty native Australian foods suppliers; however, the more convenient whole or powdered lemon myrtle leaf is readily available from herb and spice shops and many gourmet food retailers. Because of the volatility of the essential oil, it is important to purchase only small quantities (say less than 1 2/3 ounces/50 g for normal household requirements) of freshly produced lemon myrtle powder in airtight packaging. Store in the same way as other delicate green herbs, in a well-sealed container in a cool, dark place.
Cooking with Lemon Myrtle
Because the flavor of lemon myrtle resembles that of the citrus fruit so closely but lacks the fruit’s acidity, it is especially useful in recipes that are milk- or cream-based. It imparts a strong lemony flavor and won’t cause dairy products to curdle. On the other hand, it is unsuitable for extended cooking times, as the lemon flavor begins to dissipate and a strong eucalyptus flavor can begin to emerge. For this reason, lemon myrtle is more successfully used to flavor cookies, ice creams and sorbets, pasta, stir-fries, fish, and grilled meats than foods requiring longer cooking times, such as roasts and dense cakes. In addition to its use in prepared dishes, lemon myrtle is a good choice to add flavor to spice rubs and marinades for poultry and fish, flavored vinegars, salad dressings, and dips.
It can even be used as a flavoring agent in hot or iced tea. There are, however, two basic guidelines worth remembering to achieve the best results. One is to add only a small amount, say 1/4 to 1/2 teaspoon (1 to 2 mL), or 1 to 2 leaves, to 1 pound (500 g) of meat or vegetables, then taste before adding more. The other is to put lemon myrtle only in recipes that cook for a short time, never subjecting it to extreme temperatures for more than 10 to 15 minutes. The reason for this caution is that when too much lemon myrtle is used, or when it is cooked for too long, the flavor-giving volatile oils will be destroyed and a sharp, possibly unpleasant eucalyptus flavor will dominate.
Lemon myrtle is an excellent substitute for lemongrass and complements Asian stir-fry dishes, especially those with chicken, seafood and vegetables. Broiled chicken, pork and fish are given a lift when a little lemon myrtle is sprinkled on before cooking, as is smoked salmon served cold.
While some cooks like to put lemon myrtle in cakes and muffins, I generally prefer it in sweet things that are cooked more quickly at a lower heat, such as blinis and pancakes. In these quick-cooking applications, infuse lemon myrtle in a little hot water to bring out the flavor first.
Health Benefits of Lemon Myrtle
The leaves contain much essential oil (typically, 4 to 5%), which is made up almost totally of terpenoid aldehydes: citral (90 to 95%), neral and geranial. Trace constituents are myrcene, linalool, citronellal, cyclocitral and methyl-heptenone. Citral has several medicinal uses. It is a potent antiseptic and may prove useful in treating gastro-intestinal infections, including Helicobacter pylori, which is responsible for many cases of gastric ulcer. It has antispasmodic properties that help alleviate intestinal spasms, as may occur with intestinal infections or adverse reactions to foods. Overall, it has a relaxing effect.
Further, one of its modern applications is for treating throat disorders, either due to infection or to overuse and irritation. The essential oil obtained from lemon myrtle contains antimicrobial compounds and is often used as an ingredient in shampoos, therapeutic body lotions, soaps, and household cleaners. The oil is believed to possess the ability to repel fleas and is therefore a feature of some chemical-free pet shampoos.
lemon ironwood, sand verbena myrtle, sweet verbena tree, tree verbena French: Myrte citronnée, Myrte citron German: Zitronenmyrte
Backhousia citriodora Fam: Myrtaceae (myrtle family)