From flax to linen - Processing
Rippling
After retting the flax in the fields, the swaths are pressed into round bales.
These must first be loosened a bit at the beginning of the manufacturing process. This is followed by a step called rippling, in which the fruit capsules and seeds are removed with the help of a comb-like tool. Sometimes this step is skipped and carried out later.
Scutching and heckling
The long and short flax fibres are separated in a purely mechanical process.
First, the woody core of the flax plant’s stem is broken by heavy, counterrotating toothed rollers. During retting, the material connecting the woody and fibrous bast parts was dissolved so much that they can now be separated from each other during this breaking process.
The pieces of broken wood are discarded during the scutching step.
In the past, this step was done by hand using wide wooden knives. Today, it is carried out by machines with modern turbines. Only long flax fibres remain after scutching.
The last step in flax processing is heckling. It splits the flax fibres and the fibrous bast.
Afterwards, the approximately 60-to-100cm-long fibre bundles are sorted by hand and formed into bales.
Depending on the colour, purity, length and uniformity of the fibres, they are categorised into premium quality, slightly defective and inferior quality.
The long fibres are stored by batch and delivered to spinning mills.
About 14 to 21% of flax straw are long fibres.
Tow
One by-product of this process is tow – short, coarse pieces of fibre produced during the heckling phase.
Tow accounts for about 7-15% of flax straw. Higher-quality tow is used in the textile sector: it can be used as raw material for classic linen spinning mills, or shortened and refined tow can be used in staple fibre spinning mills. Medium-quality tow is used to make non-woven fibres; in the production of moulded parts or as natural insulating materials, for example.
The lowest grades are used in the production of high-quality cellulose, which is necessary for special types of papers or filters.
Shives
Shives are woody fragments that break off from inside flax plant stems during the scutching phase.
Shives are used as a basic material in lightweight building boards, as an aggregate in potting soil and, first and foremost, very successfully as animal bedding.
Linseed
The seeds of the flax plant have always been harvested to guarantee successful sowing the following year. Linseed is also edible and it can be pressed to make oil. Linseeds obtained after dew retting are often damaged, and can usually only be made into oil. Higher-quality flaxseed is typically harvested at an earlier time.
