Licorice (Glycyrrhiza glabra) is a perennial herb used as a flavoring agent and medicinal ingredient for thousands of years. Its name derives from the Greek words for “sweet root,” referring directly to the compound found in its subterranean parts. All of the characteristic sweetness comes exclusively from the extensive root system that develops beneath the soil.
The Licorice Plant’s Identity
The licorice plant is a robust perennial herb that can grow to a height of about 5 to 6 feet (1.5 to 2 meters). Its woody stems are covered in loose foliage composed of pinnate leaves, meaning the leaflets are arranged along a common stalk. During the summer months, the plant produces erect flower clusters of blue-lilac, blue-violet, or white-pink blossoms.
The plant develops a dual root structure beneath the surface. This system consists of a main taproot that descends deeply for stability, alongside an extensive network of horizontal runners, known as rhizomes or stolons. These rhizomes are the commercially sought-after parts because they contain glycyrrhizin, the compound responsible for the intensely sweet flavor. The prolific nature of these runners allows the plant to form large colonies and can make it somewhat invasive if left unmanaged.
Cultivation Requirements and Growth Cycle
For commercial production, licorice thrives best in deep, fertile, and well-drained soil, often a sandy loam, which allows its extensive root system to penetrate easily. It requires full sun exposure and a warm climate, typically succeeding in Mediterranean or subtropical regions. The plant is quite hardy once established but requires consistent moisture while avoiding waterlogged conditions, which could lead to root rot.
Propagation is most reliably achieved using root cuttings, or sections of the rhizomes, rather than seeds. Utilizing cuttings ensures consistency in the quality and flavor of the harvested product and accelerates the overall growth process. As a member of the legume family, G. glabra also fixes atmospheric nitrogen in the soil, which enriches the surrounding environment.
The most distinguishing characteristic of licorice cultivation is the long time investment required before harvest. The plant’s initial growth is slow, and it typically takes three to five years of maturation for the rhizomes to accumulate a sufficient concentration of the sweet compound, glycyrrhizin. This extended growth cycle is necessary to achieve the desired thickness and flavor intensity in the roots before they are commercially viable.
Harvesting and Extraction
The harvest of licorice root is a labor-intensive process that occurs when the plant is dormant, typically in late autumn or winter. This timing ensures the plant has stored the maximum amount of sweet compounds in the roots. The entire plant, including the extensive root system, is carefully dug up, sometimes reaching depths of several meters, requiring specialized equipment or significant manual labor.
Once removed from the ground, the thick rhizomes are separated from the soil and thoroughly cleaned. The roots are then dried, either in the sun or with artificial heat, to reduce their moisture content. After drying, they are ground into small pieces or a coarse powder to maximize the surface area for the next step.
The final stage involves extraction, where the dried, ground root material is boiled in water. This process releases the active compounds, including glycyrrhizin, into the liquid. The liquid is then filtered to remove solids and concentrated through evaporation. The result is a dark, thick syrup that can be further dried into a solid block, which is the concentrated licorice extract used by manufacturers worldwide.