If allowed to remain under water too long, the fibre is weakened by what is termed " over-retting," a condition which increases the amount of codilla in the scutching process; whilst " under-retting " leaves part of the gummy or resinous matter in the material, which hinders the subsequent process of manufacture.
At this point advantage is taken of fine dry weather to gather up the flax, which is now ready for scutching, but the fibre is improved by stooking and stacking it for some time before it is taken to the scutching mill.
By this means, not only is all the slimy glutinous adherent matter thoroughly separated, but the subsequent processes of breaking and scutching are much facilitated.
For ordinary waterretted flax two operations are required, first breaking and then scutching, and these are done either by hand labour or by means of small scutching or lint mills, driven either by water or steam power.
Hand labour, aided by simple implements, is still much used in continental countries; also in some parts of Ireland where labour is cheap or when very fine material is desired; but the use of scutching mills is now very general, these being more economical.