It is soft and somewhat dull, rather than cold and firm. The grain is sometimes finer and sometimes a little coarser, rather than smooth and slippery. It smells finely of leatherand somewhat sweet. It breathes. It absorbs moisture and releases it again. It is naturally greased, not coated. We are talking about rhubarb leather. The dried rhubarb root pieces from which the tannin is extracted smell earthy and sourly fruity.
The founder of “Rhubarb Technology”, the company from which we also source our rhubarb leather, has always liked sours. As a child, she liked to break off a stalk of rhubarb from the home vegetable garden and bite into it – raw. Anne-Christin Bansleben was practically born with a green thumb: Growing up in a small village in Saxony-Anhalt, her parents taught at the GDR agricultural school and her mother drove a combine harvester.
Today, she cultivates her business just as her parents cultivated their crops. But for many years she found them herself in the vegetable patch: for four years she and her university professor Ingo Schellenberg (who, together with a tanner, discovered the rhubarb root as a supplier of tannins in 1995, but then left it to gather dust in a drawer as research results) and her husband worked on the right cultivation method. The entrepreneurs cultivated 40 different rhubarb varieties in the university’s trial fields before they were satisfied with the results – the process had to be scalable and the tannin efficient.
The result is a leather that sets new standards in sustainability. The founders had set out to find a more environmentally friendly alternative to conventionally tanned leather – and found an answer. The acreage required is comparatively marginal, even with increasing production of rhubarb leather. This ensures that there is no competition with food crops. Thanks to rhubarb, it is possible to avoid using substances that are difficult to degrade when tanning and dyeing the skins. Rhubarb leather, unlike conventionally tanned leather, is very biodegradable: when rotting, only components are produced that can be returned to the natural cycle without hesitation. The heavy metal chromium, on the other hand, is not degradable; theoretically, chrome-tanned leather products are hazardous waste. As a reward for the efforts, the rhubarb leather received the IVN and ECARF seals of quality.
Moreover, rhubarb can be grown in our latitudes, while other plant tannins often come from distant lands, for example, tara root from South America. The Rhahaber leather a completely regional product, the complete value creation takes place in Germany. All production steps, from the cultivation of the rhubarb, to the extraction of the tanning agent, to the tanning and leather finishing, take place in Germany. The hides come from domestic livestock in Bavaria, for the most part the company uses raw hides from sustainable livestock farming. Since tanning is also done in southern Germany, there is no need to salt the raw hides to preserve them for transport. The rhubarb is grown near Magdeburg. Local value creation means that long transport routes can be dispensed with. Thanks to the combination of renewable raw materials and the technical possibilities in Germany, natural resources can be conserved and the domestic economy strengthened.
Rhubarb leather is thus a contrast to the cheap leather tanned in Asia with the help of chrome. The leather industry is very globalized these days, with most animal hides coming from Latin America and being tanned in Asia. However, many children work in the Asian tanning centers. In unclean production, the chromium III salts produce chromium VI, which is carcinogenic and can cause skin rashes or allergies. Likewise, chromium VI can damage the immune system and reproductive ability. However, workers often handle the chrome baths with inadequate protection. WHO estimates that 90% of those working in Hazaribagh – the center of the leather industry in Bangladesh – will die before they are 50 years old.
In addition, special wastewater treatment plants are needed to filter chromium out of the wastewater – unfortunately, however, the environmental standards in low-wage countries do not correspond to those in Germany. In 2013, the Blacksmith Institute and Green Cross in Switzerland ranked Hazaribagh among the 10 most contaminated places in the world. Every day, 22,000 cubic liters of toxic waste are produced there, including carcinogenic chromium. The ZDF report “Gift auf unserer Haut” (Poison on our skin) paints a similar picture of the situation in the Far East: it shows images of workers in Bangladesh standing knee-deep in broths of chromium and carcinogenic acids, toxic wastewater that is discharged unfiltered into rivers, and emaciated animals.
On top of that, chromium extraction is a resource-intensive and environmentally damaging process. The chromium salt required is mined in open pits in Asia and Africa. This results in groundwater lowering and land expropriation. The subsequent chemical conversion of the raw materials takes place with a high energy input; a large number of different chemicals and very high temperatures are required for chromium processing. Working conditions are often very poor during mining and processing.