Lemon balm (Melissa officinalis) is a fragrant herb from the mint family, recognized for its distinct citrus scent. This aroma is due to volatile compounds, primarily the aldehyde citral, found within the plant’s leaves. Proper preservation methods are necessary to stabilize these delicate volatile oils, which provide both the flavor and therapeutic properties of the herb. Successfully storing lemon balm allows its refreshing qualities to be enjoyed long after the growing season has ended.
Preparing Lemon Balm for Preservation
Harvesting lemon balm at the correct time maximizes the concentration of its aromatic oils. The leaves are generally most potent in the morning, after the dew has evaporated but before the intense heat of the day. It is best to harvest the herb just before the plant begins to flower, as the flavor can become less potent afterward.
After harvesting, rinse the leaves quickly under cool water to remove surface dirt or insects. Pat the leaves dry or use a salad spinner. Removing external moisture is important, as lingering water droplets can encourage mold growth or cause the leaves to turn dark when air-dried. Before drying or freezing, strip the leaves from the main stems, since the thicker stems retain moisture and slow the overall drying process.
Long-Term Storage Through Drying
Drying is the most traditional preservation method for lemon balm, highly effective for preparing teas. The goal is to remove moisture quickly while limiting exposure to heat and light, which degrade the volatile oils. Leaves are ideally dried at low temperatures, generally around 95°F (35°C), to maintain their aromatic potency.
Air drying is a simple option involving gathering small bundles of stems and tying them loosely together. These bundles must be hung upside down in a dark, cool location with good air circulation. Depending on the humidity, this process can take anywhere from one to three weeks.
For a faster, more controlled method, use a food dehydrator or an oven set to its lowest possible temperature. Dehydrators should be set near the 95°F to 100°F range, with the leaves spread in a single layer. If using an oven, which often cannot go below 140°F, the door must be left slightly ajar to allow moisture to escape and prevent baking. Drying is complete when the leaves are brittle and easily crumble.
Once fully dried, store the leaves in an airtight container, such as a glass jar, to prevent moisture reabsorption. The containers must be placed in a cool, dark location, away from heat sources and direct light. Storing them whole and crushing them just before use helps retain maximum flavor and aroma.
Preserving Potency Using Freezing Techniques
Freezing is an excellent alternative to drying, particularly for preserving the fresh flavor of lemon balm for culinary applications. Frozen herbs retain a stronger, more vibrant flavor profile compared to their dried counterparts. The simplest method involves flash freezing the washed and dried leaves on a baking sheet for about 30 minutes.
Once frozen solid, transfer the individual leaves quickly to a freezer-safe bag or container to prevent clumping. Air should be squeezed out of the bag before sealing to minimize frost damage. These frozen leaves can be added directly to cooked dishes, eliminating the need for thawing.
Another popular technique involves freezing the leaves in a medium like water or oil using ice cube trays. For water cubes, chopped leaves are added to the trays, topped with water, and frozen, serving as a convenient addition to teas or soups. Alternatively, chop the leaves and mix them with a mild oil, like olive or canola, before freezing. These herb-oil cubes are useful for sautéing vegetables or adding flavor to sauces.
Maximizing Shelf Life and Usage
The longevity of preserved lemon balm depends on the chosen method and storage conditions. Dried lemon balm, stored away from light and air, retains potency for six months to a year. Frozen lemon balm, especially when encased in oil or water, maintains its fresh flavor best when used within six to eight months.
To check if the preserved herb has lost quality, assess its color and scent. Dried lemon balm should retain a greenish hue, and a noticeable lemony aroma should be released when the leaves are crushed. Loss of scent or a dull, straw-like color indicates that the volatile oils have dissipated. Preserved lemon balm can be used for making soothing teas, infusing vinegars or oils, or adding a fresh, citrus note to baked goods and savory dishes.