Know Your Fiber: Zwartbles Wool

Posted on February 01 2020

Know Your Fiber:  Zwartbles Wool


Undyed, black wool is always a treat to work with, but there are relatively few breeds of sheep that can reliably produce good, spinnable black wool in large quantities. Fortunately, the adorable Zwartbles with its black fleece, white socks and a white blaze running down its forehead has survived to answer the call of spinners and felters everywhere.  Originating in the Netherlands, and once close to disappearing completely, Zwartbles have seen a resurgence of interest in their wool over the last 50 years. However, their history starts with another breed entirely.


Zwartbles are thought to have directly descended from Schoonebeker sheep, and were very popular sheep in the Netherlands right up through the late 1800s. Named after the village of Schoonebeek in a northeastern region of The Netherlands, Schoonebeker were raised by the Dutch farmers of that region for their wool, milk, and meat. More importantly, though, Schoonebeker were vital to keeping the fields healthy and fertile. At night, Schoonebeker sheep would be herded into an enclosure or barn so that their manure could be collected in the morning and applied to the fields to improve the soil. Essentially, Schoonebeker sheep were premium fertilizer on the hoof.


In the early spring, farmers would take their Schoonebeker lambs west to the livestock market at Norg and sell them to farmers from the northern province of Friesland. These Friesland farmers would fatten up the lambs on their own lush pastures, which were in turn fertilized by the sheep, before selling them once again as meat. It might not be an exaggeration to say that Schoonebeker sheep were desired for their fertilizing abilities even more than they were for their meat. However, the increasing availability of inexpensive chemical fertilizers available by the early 1900s effectively caused the Schoonebeker market to crash. No longer needing sheep manure to fertilize their fields, farmers began keeping fewer and fewer sheep.


A group of farmers in Northern Friesland took stock of the early 1900s sheep market and saw that milk sheep were still in demand. They decided to try their hand at using Schoonebekers to develop a multi-purpose breed that while primarily used for milk could also supply wool and meat. As far as farming historians can tell, they began by selecting lambs of a particularly unique coloring from the Schoonebeker breed. Although Schoonebeker sheep were usually some combination of speckled or spotted black and white, sometimes lambs would appear that were almost all black with perhaps some white socks and a bold white blaze reaching from their foreheads all the way down to their noses. Thinking to use this attractiveness as a marketing tool, these Schoonebeker market lambs became the base stock of a new breed of sheep – the Improved Schoonebeker. These Schoonebekers were bred with Texel sheep and Friesian milk sheep, breeds that were well regarded as good milkers. Soon the breeders had a sheep that was both striking in appearance, and a good milker. Success followed, and the Improved Schoonebekers began to be raised right alongside other dairy animals.


Improved Schoonebekers, soon called Zwartbles after their color and markings (zwart = black, bles = blaze), were relatively popular for several decades after their development. However, like many breeds of sheep, they saw their popularity quickly decline around WWII. The necessity of producing large amounts of food and wool as quickly and efficiently as possible meant that sheep previously raised for meat or milk were replaced with cattle, who could easily produce greater quantities of both. As a result, sheep milk cheeses were quickly overtaken by cow milk cheeses, to the point that sheep cheeses were very difficult to find. Even today, Gouda, one of the best-known Dutch cheeses outside of the Netherlands, tends to be made with cow milk. Prior to the decline of milk sheep in the Netherlands it was not uncommon for Gouda to have been made with sheep milk.


By the mid-1970s, Zwartbles were listed as critically rare by the Dutch Rare Breed Survival Trust. No longer in demand for their milk, wool or meat, it took only a few decades for stocks to rapidly decline. By 1978 there were only around 250 purebred Zwartbles left, and of those there were around 55 or fewer breeding ewes. This time, though, it was wool spinners to the rescue. The 1970s had seen an increasing number of people taking up traditional crafts that had lost popularity during the war years. Spurred on by multiple cultural factors across Europe and North America, such as the renewed popularity of crocheting and knitting, back-to-the-earth movements, a wish to preserve historical skills and more, hand spinning saw a resurgence among crafters and fiber artists. Spinners then, as now, were always looking for the next interesting fiber to play with, and they found it in the endangered Zwartbles. The tight, naturally black fleeces became quite popular among European hand spinners, and Zwartbles farmers began to increase the sizes of their flocks to accommodate the demand for wool from the now popular sheep. By 1985, Dutch farmers began a Zwartbles flock book to track their breeding lines, which was shortly followed by the first Zwartbles being introduced to the U.K. in 1986. Today, Zwartbles are particularly popular in the U.K. with over 12,500 of them being recorded in current flocks. Today’s Zwartbles are usually raised for both their wool and their meat.


Zwartbles wool comes in a range of blacks, from dark black to brown-black. Fleeces from multiple sheep are usually processed together, producing a top that is typically a very, very dark brown. With an average width of 27-32 microns, Zwartbles wool is solidly in the medium range of wools. It has a strong crimp and quite a long staple at 4-5 inches in length. Most crafters and fiber artists find that it is most suitable for outerwear, blankets, and other projects that require a sturdy wool – it is also excellent for felting projects.


Want to try out some Zwartbles for yourself? Check out our Zwartbles top available at our shop and on our website. Happy crafting!

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