Peppermint oil

25.05.17

Peppermint oil is derived from the Peppermint plant (Mentha piperita), a member of the Lamiaceae plant family. The Lamiaceae family includes a range of mints, marjoram, oregano, rosemary, sage and other mainly perennial, herbaceous plants and small shrubs. Peppermint is native to Europe but is widely cultivated throughout all regions of the world.

Overview

Peppermint, as with other mint-type plants, is a summer-growing perennial plant. It is a low-growing plant that readily sends out stolons (runners), which develop new roots and shoots at the nodes. Under good growing conditions, the square-shaped stems generally reach 1m in height at maturity.

Peppermint has a long tradition of medicinal use, with archaeological evidence placing its use at least as far back as ten thousand years. In modern times, the oil in the leaves of the peppermint plant is distilled and its components used in wide range of applications including toothpaste, mouthwash, chewing gum, confectionary and as a flavouring agent in food. The oil may also be used in cosmetics and aromatherapy.

The United States of America (US) is the main producer of peppermint oil in the world and accounts for half of the world trade. Peppermint oil in Australia, although relatively small, is a maturing industry and its interests are represented by The Essential Oils Producers Association of Australia.

Facts and figures

  • Peppermint is a perennial, herbaceous plant and can produce up to two harvests in a season under good growing conditions
  • A major cost in the establishment of a peppermint crop is the purchase of stolons for planting
  • Rust is a major production risk for peppermint
  • Significant capital outlay for dedicated, specialised distillation equipment may be required
  • The oil is obtained from steam distillation of the leaves and the oil may be further processed into different components
  • The oil is used in the confectionery, food flavouring, cosmetic and aromatherapy industries
  • The United States of America is the largest producer of peppermint oil and dictates the trade for the oil

Production status

The United States of America is the world’s main producer of peppermint oil, accounting for half of the world trade. Production in the United States is generally around 3,000 tonnes of oil per year. India has become a significant peppermint oil producer in recent years with production levels rising to around 450 tonnes a year and oil from the better suppliers is rapidly improving.

Australian import and export prices for peppermint oil have generally been declining over the past 20 years. The main export markets for Australian peppermint oil were Hong Kong, Taiwan, Indonesia, Malaysia, and Singapore.

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Map of current and potential growing regions

Uses

Peppermint oil has a long tradition of medicinal use, with archaeological evidence placing its use at least as far back as ten thousand years. Peppermint continues to be a popular and important ingredient in toothpaste, mouthwash, chewing gum and as a flavouring agent in food. The oil is also used in aromatherapy.

Production Requirements

Growing regions

The Australian peppermint industry was established in Tasmania and production largely occurs in Tasmania and Victoria.

Within the mint family, peppermint is the most dependent on growing conditions in order to produce good quality oil. The species requires long day lengths, with warm to hot day temperatures and cool nights, to produce the right balance of oil compounds. Most of Tasmania is suitable for production and in Victoria, the agricultural areas close to the Great Dividing Range in the state’s north east are suitable.

Soil type

Mint species generally thrive in rich, moist, well-drained soil with a pH of 6.0–6.5. It is important to avoid low lying areas or too much water during winter, as areas of a crop that are subject to waterlogging will not perform vigorously and plants may even die.

Climate

Peppermint requires a temperate climate with warm to hot conditions during the day and cool nights. Day length is also important, with long day lengths required for the plant to produce the right balance of oil compounds.

Peppermint grows well in areas with annual rainfall of 600–800mm. However, as a summer-active plant, irrigation will be required to meet the water demands of a peppermint crop.

Peppermint is frost tolerant during the dormant period although there might be some dieback of surface stolons after severe frost periods. This does not normally affect productivity in the next growing season.

Varieties

The peppermint variety Black Mitcham is the original line selected for peppermint oil production and is cultivated in Australia. It is a highly valued variety but has become susceptible to the soil-borne fungal disease, verticillium wilt overseas. Todd Mitcham is a more verticillium wilt-tolerant selection, which now forms the bulk of the world’s production. Both varieties are present in Australia where verticillium wilt has not been detected.

The crop has high water requirements during summer and irrigation is required to maintain good growth. However, soil moisture levels should be monitored as inundation during the growing season has detrimental effects on a crop.

In recent years, a complex nutrient deficiency involving sulphur, copper, boron and molybdenum was identified in peppermint crops in Tasmania. Critical levels in plant tissues were determined for each of the elements involved. Research has recommended a fertiliser formulation to correct deficiencies in field-grown crops and achieve high oil yields.

Weeds, pests and diseases

Weed control programs must be implemented, not only to reduce plant competition but more importantly to eliminate any contamination of the peppermint oil with oils from other herbage.

Mint rust (Puccinia menthae) is the most significant disease problem of all the mint plants, which, if left unchecked, will totally defoliate the plants. Registered fungicides should be used at appropriate times throughout the crop’s life cycle.

Pests of peppermint include cut worms, two-spotted mite, brown vegetable weevil and wingless grasshopper. An integrated pest management system has been developed for two-spotted mite in peppermint.

There is a range of herbicides, fungicides and insecticides registered for use in mint crops or available under minor use permits, but these should be reviewed regularly to ensure currency.

Planting and crop management

Planting and crop management techniques in Australia are based on those of peppermint production in the United States.

Peppermint is a perennial crop, therefore a well-planned fallow and weed eradication program before establishment is critical for the long-term viability of the crop.

The peppermint herb is sterile and must be propagated vegetatively using stolons, which is a major cost of establishing a peppermint enterprise. Stolons planted at a nursery site of 1ha will provide enough material to plant 7–10ha the following year. The stolons may be planted using a specially designed planter or by spreading the plant material over the field followed by light cultivation of the soil to work in the stolons.

Infrastructure Requirements

A peppermint crop can be established using a specially designed planter, or by spreading the stolons with a machine such as a muck spreader, followed by lightly cultivating the soil.

Harvest requires a mower or windrower, and the wilted plant material is gathered and chopped with a conventional forage harvester, and fed into tubs to be transported to the distillation plant.

The distillation of peppermint leaves will require dedicated equipment such as boilers, condensers, and separators. Given the bulk of leaf material involved, the distillation plant needs to be in close proximity to the field. Depending on the planned size of the operation and the skills required, contract services should be considered for the distillation process.

Harvesting & Processing

Mint crops are usually mown using conventional hay mowers or windrowers, from January through to March. It is important to use machinery that avoids bruising the leaves at any time during harvest as this will result in loss of oil. The harvested peppermint is left in windrows in the field and once it is wilted, the material is gathered and is chopped directly into a distillation tub using a forage harvester. It is important to monitor the moisture content of the crop before and during these field activities, to ensure complete and economic oil extraction. It is important not to over dry the harvested leaf material as it will shatter and result in loss of oil.

The plant material is transported to the distillation facility where steam is passed through the herb and the resulting steam and oil vapour is condensed and separated. Stainless steel condensing and separation equipment should be used and a quality assurance program followed to ensure no contaminants are present.

Markets & Marketing

Australian import and export prices for peppermint oil have generally been declining over the past 20 years.

There are a wide range of peppermint qualities traded and for the most part peppermint sells in a commodity market. Significant price fluctuations can be experienced over relatively short time frames depending on the supply and demand pressures. International trade is predominantly in USD and relative exchange rates can have a significant effect on producer returns. However, Australian production meets the highest quality criteria and there has been some firming of prices within that sector in recent years.

Within the peppermint oil industry there are opportunities to supply harvested material to a processer; to grow and distil peppermint and supply the oil to a company for blending or refining; or for full vertical integration from growing to marketing. Potential entrants to the peppermint oil industry are advised to carefully research and understand the production chain, and comprehensively investigate new market opportunities and niches.

Risks & Regulations

Risks/challenges

The main production risk for peppermint in Australia is the rust fungus, which will totally defoliate the plants if left unchecked. A treatment program of fungicide applications at appropriate stages of the disease cycle helps reduce the impact of the disease.

Marketing of the oil can also be a challenge as the markets are unpredictable and are largely influenced by the characteristics of the United States peppermint oil market, which dominates the international market. Growers should consider producing peppermint under a contract.

Regulatory considerations

There are regulations imposed throughout the value chain for peppermint production. For example:

  • If a potential grower is considering investing in a distillation plant, permits will be required from local government in the shire or region where the building application is being sought.
  • There is no Australian standard for peppermint oil. The ISO hold an international standard for the oil.
  • Peppermint oil that is to be traded into the European Union must be compliant with the European Union REACH Regulations. REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) addresses the production and use of chemical substances and their potential impacts on both human health and the environment.
  • For therapeutic use, any products containing peppermint oil have to be listed on the Australian Register of Therapeutic Goods. This organisation also covers the required packaging for therapeutic products.

Regulatory issues for essential oils in Australia are overseen by the industry association The Essential Oils Producers Association of Australia.

Publications

Publications/information
Emerging animal and plant industries: Their value to Australia RIRDC report (2014)

Increased Yields from Peppermint Crops through Improved Micro nutrient Nutrition (Stage 2) RIRDC publication (2013)

Peppermint Nursery Stock: Rejuvenation of Peppermint crops through establishment of quality nursery stock
RIRDC publication (2007)

Increased Yields from Peppermint Crops
 RIRDC publication (2005)

Integrated Pest Management in Peppermint Growing in SE Australia
 RIRDC publication (2002)

The Impact of Double Harvesting on Victorian Peppermint Crop Productivity
 RIRDC publication (2002)

Production of Peppermint oil – a model of best practice for TAS and VIC
 RIRDC publication (2000)

Communicating best practices in peppermint production
 RIRDC publication (2000)

Control of mint rust on peppermint
 RIRDC publication (1999)

Other resources

The International Aromatherapy and Aromatic Medicine Association Inc. is an independent not for profit organisation that supports aromatherapy practitioners in Australia and overseas

The International Federation of Essential Oils and Aroma Trades represents the interests of the global flavour and fragrance industries

The Therapeutic Goods Administration is Australia’s regulatory authority for therapeutic goods and packaging requirements for therapeutic goods

International Standards Organisation develops and publishes international standards

Image Gallery

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Peppermint crop (source Essential Oils of Tasmania)

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Peppermint in-field mid season (source Essential Oils of Tasmania)

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Peppermint - cut edge of crop that has been harvested

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Peppermint crop mid season (source Essential Oils of Tasmania)

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Peppermint crop windrowed in preparation for harvest (source Essential Oils of Tasmania)

Related Publications

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Emerging Animal and Plant Industries - Their Value to Australia (2nd Edition)

15.05.13

Increased Yields from Peppermint Crops through Improved Micro nutrient Nutrition (Stage 2)

23.04.07

Peppermint Nursery Stock: Rejuvenation of Peppermint crops through establishment of quality nursery stock

03.08.05

Increased Yields from Peppermint Crops