Mimosa extract from Acacia Mearnsii

The benefits of tanning LEather the natural way

STAFF WRITER   |   13 October 2021

Leather is among the earliest materials ever used by man and it’s earliest use can be traced to the Stone Age, where hunter gatherers used the skins of their kills for primitive shelter, clothing and toolmaking. It is hypothesised that leather tanning was discovered when skins were discarded into pools of water and fallen leaves on the forest floor.

Left long enough, the tea of composting leaves and water would have transformed the texture, colour and odour of the skins, making them more durable and useful than the untreated hide. Through trial and error, vegetable tanning was discovered in the neanderthal era, delivering a material that is still widely used today.

Natural tanning has a rich history. The oldest leather tools (stones sharpened to scrape the hides) have been dated to 82,000BC and were discovered in NTE’s home country of South Africa. 

The oldest leather footwear item, known as the Areni-1 Shoe, is over 5,500 years old and remains in outstanding condition.

Natural tanning through the ages incorporated a range of different ingredients to aid in the tanning process. Early processes used salt, clay, urine, lime, brains, vinegar and tree bark. The word tannin is derived from the Latin word tannum, meaning oak bark. Extracts from trees like cedar, hemlock, oak and chestnut proved highly effective because of the above average levels of tannin. 

Versatility and utility in a single tree: Acacia Mearnsii (Black Wattle) offers one of the richest sources of naturally occuring tannin concentrate in its bark, and a wide range of uses from the wood beneath.

Quebracho tannins are extracted from the heartwood.

Today there is an increasing consumer demand for naturally tanned leather, but many of the natural alternatives also pose key environmental issues. Quebracho and chestnut, both good sources of tannin for the leather industry, are slow growing trees and are not sourced from reforested plantations. While chestnut trees are not always clear cut and killed for their tannins, quebracho trees are and this has had a significant impact on forests in Uruguay and Argentina, where the trees typically take a century to reach maturity. This environmental impact has been a valid criticism of vegetable tanning.

Acacia Mearnsii – the SUSTAINABLE alternative

Also known as black wattle, the acacia mearnsii is a legume that has exceptionally high levels of natural ‘catchecol’ tannins within the bark. Indigenous to Australia, the species was introduced to South Africa in the early 1800s, where it was utilised for firewood and construction. The black wattle grows exceptionally well in South Africa’s ‘mist belt’ that extends from the KwaZulu-Natal Midlands to the Lowveld. Some 130,000 hectares of black wattle are currently being grown commercially in the region, mostly by small-scale farming operations. 

Black wattle is a hardy, rapid growing tree that is capable of thriving in conditions where other timber cannot, and can survive even extreme drought conditions. Reaching maturity in only 8 to 10 years, the tree is a nitrogen-fixer, which enriches and develops the soil it grows in. Another key feature of the tree is its natural resistance to pests, which precludes the need for any pesticides, resulting in an extract that is free of toxins and completely organic. The short growing cycle, soil restorative qualities, pest resistance and excellent return on investment from land that would otherwise not be commercially viable makes black wattle an excellent choice, particularly for small-scale and environmentally conscious growers.

Black wattle plantation in Pietermaritzburg, South Africa.

NTE Mimosa’s wattle plantations in South Africa are certified by the Forest Stewardship Council (FSC), and have always been maintained with a particular focus on careful land and resource management principles. Forests are not converted from indigenous areas of any conservation value, and environmental impact assessments are undertaken to ensure both local community and ecology is protected. 

NTE is wholly owned by the wattle growers, with over 700 shareholders ranging from large scale operations to small community grower operations. NTE is committed to supporting and educating its growers through technical advice, seed stock and equipment, to ensure that benefits are seen at every level of the wattle supply chain.


NTE today is the world’s largest single grower of acacia mearnsii, with over 65,000 hectares under management. The wattle bark is processed and the mimosa extracted at two world-class factories at Iswepe and Hermannsburg, using patented processes. At every step of the journey from seedling to final product delivery, NTE aims to minimise the environmental and carbon impacts of its operations. The wood from acacia mearnsii is also a sought after commodity, providing a high-yield pulp and dense woodchip product.



NTE is committed to supporting and uplifting the businesses of our shareholders and growers. Through community-based enterprises such as Amandla Emvelo CPA, Eyethu Farming, Ikhasi Agri farming, Isigelane CPA and Ituba Agriculture, NTE offers financial, mentorship and forest stewardship support, and provides a secure market for their bark.


NTE is the world’s leading researcher into mimosa and its applications across a wide range of industry verticals. The company now markets 13 variants of wattle extract for leather tanning, ranging from the technologically advanced Mimtan AT1, which delivers a light colouring and superior lightfastness, ideal for the automotive and fashion industries, to Mimosa FS, which tans leather up to 30% faster than standard timeframes. 

NTE Mimosa specialises in helping tanneries to incorporate mimosa extract into traditional chromium tanning. Our experts can guide you in choosing the right combination of extracts to deliver the tanning and dyeing outcome you are looking for. For more information, get in contact in the form below or explore our product range.

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