The insole (or midsole)
Made from cowhide, its vegetable tanning process provides it with special and antagonistic characteristics: rigid and sturdy yet flexible, while having bactericidal properties.
Cow parts such as the neck and skirt are selected for this piece. This leather is also used to produce welts.
They are usually 2.5 to 3-mm thick and are cut with an automatic machine at Berwick, which is a complex task because the cutting zone is never flat due to its origin. The insole is an important part of the shoe as it plays the role of the “chassis”, which the cutting and welt is sewn to.
Once cut, a thin nylon webbing (the wall) is stuck around its perimeter that will support the sewing. In handmade shoes, this wall is constructed on the actual insole, and it is cut with a knife to obtain a lip that will fill the role of the nylon webbing.
For the sake of convenience, this insole is anatomically moulded with an average pattern scaled according to size, and then applied to the shank, a metal support that makes the shoe bend exactly where it needs to. The shank is attached with adhesive and covered with nylon. This is normally applied after the welting and adding the cork agglomerate (manually placed with a drop of glue). Our system allows this placement to be much more accurate. Once completed, criss-cross grooves are made on it to help it flex more easily.