Issue No 6, July 1996.

NOTICE: Hard copies of the Australian New Crops Newsletter are available from the publisher, Dr Rob Fletcher. Details of availability are included in the Advice on Publications Available.

15.2. Licorice: An absolutely delicious crop

We suspect that few of those who enjoy licorice and licorice-based sweets are aware that it has its origin in the root of a plant and that it has been used as a sweet and as a herbal medicine for thousands of years. In this article Isabell Shipard gives an insight into the history of licorice, its uses and the botany and production of the licorice plant. More complete information on licorice is contained in a booklet "Absolutely Delicious Licorice' obtainable from the author (see the List of New Crop Publications for details)

While the origin of licorice is uncertain, it is believed to have originated in the East and has been grown since early times in China, Persia, Turkey, Syria, Iraq, Pakistan, northern India, Russia, north Africa and the Mediterranean countries. Currently it is grown commercially in Spain, France, Russia, Germany, England, the Middle East and Asia. In the early 16th Century, licorice began to be cultivated in the monastery garden at Pontefract, England and this later became the centre of the licorice confectionery industry for which it is still renowned.

Commercial licorice is derived from the roots of the leguminous plant Glycyrrhiza glabra. The genus name well describes the main feature of the plant as it derives from the Greek word glucos meaning sweet and from riza meaning root. The sweet taste of the root comes from a compound glycyrrhizin, reputed to be 50 times sweeter than refined sugar.

The plant is a very hardy deciduous perennial bush that grows to a height of 1-2 metres. It has spreading pinnate leaves and produces lavender-blue pea-like flowers in a spike-like cluster. It produces small flat pods 2-3 cm in length which turn brown at maturity. The pods contain 1-7 small dark kidney shaped seeds about the size of a pinhead. The plant becomes dormant during the winter and sheds its leaves. The plant has a deep taproot and also produces horizontal stolons which spread out from the main plant just under the soil surface. In the spring, the plant produces new shoots from buds on the underground stolons. The development of 'runners' or horizontal stolons indicates that the root system has developed to the stage where it can be harvested.

Commercial propagation is by seed or by cuttings from the stolons. The seed has a hard seed coat and needs to be scarified prior to sowing. Germination and early seedling growth is often slow so propagation from root cuttings is preferred. Root cuttings 20-40 cm long are used and these can be planted vertically into the soil. Planting out can be done successfully in Queensland during spring, summer and early autumn. As with any root crop, a loose friable soil is preferable. Growth in clay soils can be improved by the application of gypsum and compost and by planting on raised beds. Licorice grows well in warm temperate and sub-tropical climates and is said to do well wherever citrus can be grown.

Grown commercially, the plantation is established with root cuttings in the early spring or late summer/early autumn with 30 cm between plants and 60 cm between rows. The land is worked deeply to provide a friable seedbed which will favour root growth. The plants make limited growth for the first two years, growing only to a height of 30 to 50 cm. Because of this slow growth, commercial growers often plant quick-growing vegetable crops between the rows of licorice during the first two years.

The crop is ready for harvesting in the autumn of the third or fourth year. The usual practice is to carefully remove the soil between the rows, exposing the roots at the sides. The whole plants are then removed and the soil placed in the trench. The roots are then washed and cut into lengths 30 to 60 cm long, sorted and graded. For commercial production, the root is sold fresh but for home use the roots can be airdried or dried artificially at a temperature of 30 to 40C. Commercial yields of fresh root range from 1 to 5 tonnes per hectare.

Commercially, the licorice extract is produced by fine-cutting the roots or crushing them to produce a pulp. The crushed or cut material is then boiled with water and the extract evaporated to produce either a liquid or solid form. The latter is rolled into sticks 2-3 cm in diameter and 15 cm long known as Hard Extract of Licorice. Unfortunately, much of the licorice sold today as strap or yard long licorice is not pure licorice but a processed lolly which contains other ingredients such as molasses, treacle and aniseed.

The literature on the uses of licorice is voluminous. While it is usually seen as a sweet, it is much more widely used around the world as a herbal medicine. The list of complaints for which licorice is claimed to be effective is so extensive that it appears to be a universal panacea. It is generally claimed to be completely safe but there have been a few documented cases where overindulgence of highly concentrated licorice extracts has created serious adverse effects requiring hospitalisation. There are some medical conditions which are aggravated by licorice but for normal healthy adults there is no real risk in using licorice in moderation and its healing benefits far outweigh the risks.

There are only small plantings of licorice in Australia and all have been only recently established. There are many unknowns at the moment. There are no official records of the amount and form of licorice imported into Australia or of the value of those imports. It is also impossible to get accurate information on the amount of licorice extract that is obtained from the recovered roots. In the absence of data on the value of the product and the content of licorice in the roots it is impossible to assess the commercial potential of the crop. Although licorice appears to be widely used in sweets and confectionery, as mentioned above much of the material sold as licorice is in fact an artificial product containing little or no real licorice.

Contact: Dr Rob Fletcher, School of Land and Food, The University of Queensland Gatton College, 4345; Telephone: 07 5460 1311 or 07 5460 1301; Facsimile: 07 5460 1112; International facsimile: 61 7 5460 1112; Email: r.fletcher@mailbox.uq.edu.au

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originally created by: GK; latest update 6 June 1999 by: RF