Rooibos

Green rooibos tea

Rooibos tea in a glass

Rooibos tea with milk

A rooibos-infused liqueur and rooibos tea

Rooibos is usually grown in the Cederberg, a small mountainous area in the region of the Western Cape province of South Africa.[2]

Generally, the leaves undergo an oxidation (often termed "fermentation" in common tea processing terminology). This process produces the distinctive reddish-brown colour of rooibos and enhances the flavour. Unoxidised "green" rooibos is also produced, but the more demanding production process for green rooibos (similar to the method by which green tea is produced) makes it more expensive than traditional rooibos. It carries a malty and slightly grassy flavour somewhat different from its red counterpart.[3]

Rooibos tea is commonly prepared in the same manner as black tea, usually without or with a little milk, and/or sugar or honey. Other methods include a slice of lemon and using honey instead of sugar to sweeten. It is also served as espresso, lattes, cappuccinos or iced tea.[4]

As a fresh leaf, rooibos contains a high content of ascorbic acid (vitamin C),[5] which is lost when made into tea.

Rooibos tea does not contain caffeine[6][7] and has low tannin levels compared to black tea or green tea.[5] Rooibos contains polyphenols, including flavanols, flavones, flavanones, dihydrochalcones,[8][9] aspalathin[10] and nothofagin.[11]

The processed leaves and stems contain benzoic and cinnamic acids.[12]

Rooibos grades are largely related to the percentage "needle" or leaf to stem content in the mix. A higher leaf content results in a darker liquor, richer flavour and less "dusty" aftertaste. The high-grade rooibos is exported and does not reach local markets, with major consumers being the EU, particularly Germany, where it is used in creating flavoured blends for loose-leaf tea markets.

Three species of the Borboniae group of Aspalathus, namely A. angustifolia, A. cordata and A. crenata, were once used as tea. These plants have simple, rigid, spine-tipped leaves, hence the common name 'stekeltee'. The earliest record of the use of Aspalathus as a source of tea was that of Carl Peter Thunberg, who wrote about the use of A. cordata as tea: "Of the leaves of Borbonia cordata the country people make tea" (Thunberg, July 1772, at Paarl). This anecdote is sometimes erroneously associated with rooibos tea (Aspalathus linearis).[13]

Archaeological records suggest Aspalathus linearis could have been used thousands of years ago, but this does not imply they made rooibos tea in precolonial times.[14] The traditional method of harvesting and processing rooibos (for making rooibos infusion or decoction tea) could have, at least partly, originated in precolonial times. However, it does not necessarily follow that San and Khoikhoi utilised this method to prepare a beverage that they consumed for pleasure, as tea.

The earliest available ethnobotanical records of rooibos tea originate in the late 19th century. No Khoi or San vernacular names of the species have been recorded. Several authors have assumed that the tea originated from the local inhabitants of the Cederberg. Apparently, rooibos tea is a traditional drink of Khoi-descended people of the Cederberg (and "poor whites"). However, this tradition has not been traced further back than the last quarter of the 19th century.[13]

Traditionally, the local people would climb the mountains and cut the fine, needle-like leaves from wild rooibos plants. They then rolled the bunches of leaves into hessian bags and brought them down the steep slopes using donkeys. Rooibos tea was traditionally processed by beating the material on a flat rock with a heavy wooden pole or club or a large wooden hammer.[13]

The historical record of rooibos uses in precolonial and early colonial times is mostly a record of absence. Colonial-era settlers could have learnt about some properties of the Aspalathus linearis from pastoralists and hunter-gatherers of the Cederberg region. The nature of that knowledge was not documented. Given the available data, the origin of rooibos tea can be viewed in the context of the global expansion of tea trade and the colonial habit of drinking Chinese and later Ceylon tea. In this case, the rooibos infusion or decoction served as a local replacement for the expensive Asian product.[14]

It appears that both the indigenous (San and Khoikhoi) and the colonial inhabitants of rooibos-growing areas contributed to the traditional knowledge of rooibos in some way. For instance, medicinal uses might have been introduced before the eighteenth century, by Khoisan pastoralists or San hunter-gatherers. And the utilisation of the Aspalathus linearis for making tea, including the production processes, such as bruising and oxidising the leaves, are more likely to have been introduced in colonial times, by settlers accustomed to drinking Asian tea or its substitutes.[14]

In 1904, Benjamin Ginsberg ran a variety of experiments at Rondegat Farm, finally curing rooibos. He simulated the traditional Chinese method of making Keemun by fermenting the tea in barrels. The major hurdle in growing rooibos commercially was that farmers could not germinate the rooibos seeds. The seeds were hard to find and impossible to germinate commercially. Medical doctor by profession and business partner to Ginsberg, Pieter Lafras Nortier ascertained that seeds require a process of scarification before planting in acidic, sandy soil.[15][16]

By the late 1920s, growing demand for the tea led to problems with supply of the wild rooibos plants. As a remedy, Dr Pieter Lefras Nortier, district surgeon in Clanwilliam and avid naturalist, proposed to develop a cultivated variety of rooibos to be raised on appropriately situated land. Nortier worked on cultivation of the rooibos species in partnership with farmers Oloff Bergh and William Riordan, and with encouragement from Benjamin Ginsberg.[14]

Bergh harvested a large amount of rooibos in 1925 on his farm Kleinvlei, in the Pakhuis Mountains. Dr Nortier collected seeds in the Pakhuis Mountains (Rocklands) and in a large valley called Grootkloof and these first selected seeds are known as the Nortier-type and Redtea-type.[17]

In 1930 Nortier began conducting experiments with the commercial cultivation of the rooibos plant. Dr Nortier cultivated the first plants at Clanwilliam on his farm Eastside and on the farm Klein Kliphuis. The tiny seeds were very difficult to come by. Dr Nortier paid the local villagers £5 per matchbox of seeds collected. An aged Khoi woman found an unusual seed source: having chanced upon ants dragging seed, she followed them back to their nest and, on breaking it open, found a granary.[18]

Dr. Nortier's research was ultimately successful and he subsequently showed all the local farmers how to germinate their own seeds. The secret lay in scarifying the seed pods. Dr Nortier placed a layer of seeds between two mill stones and ground away some of the seed pod wall. Thereafter the seeds were easily propagated. Over the next decade the price of seeds rose to £80/pound, the most expensive vegetable seed in the world, as farmers rushed to plant rooibos. Today, the seed is gathered by special sifting processes. Dr Nortier is today accepted as the father of the rooibos tea industry.

The variety developed by Nortier has become the mainstay of the rooibos industry enabling it to expand and create income and jobs for inhabitants of rooibos-growing regions.[14] Thanks to Nortier's research, rooibos tea became an iconic national beverage and then a globalised commodity. Rooibos tea production is today the economic mainstay of the Clanwilliam district. In 1948 The University of Stellenbosch awarded Dr Nortier an Honorary Doctorate D.Sc (Agria) in recognition for his valuable contribution to South African agriculture.

Life history and reproduction

Aspalathus linearis has a slim endemic range in the wild, however cultivation techniques to maximize production have been effective at maintaining reproduction for consumption in correlation with the demand of the Rooibos tea industry.

The two pathways of response for Rooibos after a fire. Fynbos plants like A.linearis are fire dependent, however there are two different responses.

A. linearis is a legume and therefore an angiosperm that produces an indehiscent fruit. Its flowers make up a raceme inflorescence. Seed germination can be slow but sprouting can be induced with acid treatment.[19] The seeds are hard shelled and often need scarification[20] Like other members of the Genus,  A. linearis is  considered a part of the fynbos ecoregion, exclusive to the Cape Floristic Region, which can be dependent on fire for reproduction. It is often grouped with the honeybush, another fynbos plant from Southern Africa used for tea. For A.linearis, Fire can stimulate resprouting in the species, however this sprouting is less than in other fynbos plants. A. linearis can be considered facultative and obligate sprouters and have lignotuber development for after fires. Typically, there are two classifications of A. lineraris in response to fire: reseeders and resprouters. Reseeders are killed by fire, but the fire also stimulates the reestablishment via seeds. Resprouters are not killed during a fire, but resprout via the lignotubers established in the earth.[21] Like most legumes, there is a symbiotic relationship between rhizoids and the underground lignotuber structure that promote nitrogen fixation and growth. The nitrogen content in the soil is an important environmental factor for growth, development and reproduction. It has been suggested that there are multiple ecotypes of A. linearis that have different selected methods of growth and morphology dependent on the environment.[22] It is unclear how many ecotypes their might be given they limited geographic range, and the limited literature about genetic diversity. It has also been suggested that resprouting populations and reseeding populations have been selected for based on the environment as a way to reduce genetic bottlenecks, however it is unclear if this promotes certain reproductive strategies over others.[23] Wild populations can contain both sprouting and non-sprouting individuals however cultivated rooibos are typically reseeders not resprouters and have higher growth rates. Cultivated A. linearis can be selected for to have certain traits that are desirable for human use. Cultivated plants are diploid with a base chromosome number of 9(2n=18 chromosomes) however there is limited understanding of how this might differ in ecotypes[21] The selection process can include human mediated pollination, fire suppression, and supplementing soil contents.

Seeds of wild populations are dispersed by ant species. The use of ants as dispersers limits the amount of parent-offspring and sibling-sibling competition.[24] Ants also are helpful in dispersion as they reduce the susceptibility of seeds to other herbivores. A. linearis is not found to be significantly pollinated by Cape honey bee’s like many other Fynbos plants suggesting an alternative way of primary pollination.[25] It is likely that wasps play an important role in pollinating the flowers and some species are thought to be specially adapted to accessing the A. linearis flower.[26]

• Cyclopia (plant)
• Rooibos wine

• Media related to Aspalathus linearis at Wikimedia Commons