Saturday, October 10, 2009

Dew Retting Flax



Some of my readers have asked for directions on dew retting flax. I asked Randy Cowan of Biolin Research and Crop Fibers Canada in Saskatchewan if he would write a short article for us on the procedure. Thanks, Randy, for taking the time to inform us of some of the ins and outs of dew retting flax.

Here's what Randy said:

"When harvesting flax straw for fiber production, the flax straw is pulled out of the
ground, including the roots, and laid on the ground in a thin even layer with the stems
aligned. Consistent stem diameter and a thin layer will ensure even retting. When the
stems are retted on one side the straw must be turned over to ret on the other side.
After a heavy rain turn the flax to ensure an even ret and to stop rotting on the ground
side.

Dew retting is simple exposure of the straw to the weather for 2–3 weeks, depending
on weather; it may take up to 8 weeks, until the dew and rains have removed the
waxes and resins making the fiber loose from the stalk. In the dew retting process,
the pectins and lignins are dissolved by the interaction of molds, warm air and
moisture. The stems will turn a silvery grey color when retting is completed. Dew
retting is unpredictable because it is dependent on the rains or dew in the fall. If it is a
dry fall, sprinkle the flax every few days with water (avoid treated water, and/or tap
water, as chlorine will hinder microbial growth on the stems).

To tell if the stems are retted dry a few stems. Grab the straw and break a section,
retting is complete if the fiber does not stick to the woody core.
Once the straw has been fully retted, dry the stems before decorticating."

It is possible to over rett the flax. Over retted flax has weak fiber that breaks when breaking and hackling. Properly retted flax stems will break easily when dry, but the linen fibers within them will remain intact. Experience will help you get it just right. If its not retted long enough it will be very difficult to break with your flax break and the fibers will remain in their bundles within the sheath, without separating into individual fibers.

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