Split Leather Definition

If a skin is divided into several layers over the entire surface, this process is called "splitting". Thicker leather, mostly cow leather, which is 5 to 10 millimetres thick, is split. The obtained layers are designated as grain split or top-grain split and flesh split. Sometimes, the leather is thick enough for a middle split. The split, separated from the grain split, is also called drop split. The drop-split leather is rough on both sides like the back of a leather.

When adjusting the splitting machine, the tanner must take into account that the thickness of the skin is higher at this stage due to the water content of the wet skin. The water content of a wet skin is three times heavier than the dry weight of leather. This water content also makes the leather thicker. The tanner has to consider this difference in thickness when adjusting the splitting machine so that the desired leather thickness is achieved once the leather is dry.

The tanning method also influences the thickness at which leather must be split. Vegetable tanning agents fill the leather more, which results in a thicker leather. Thus, the technician at the splitting machine has to take many factors into account in order not to produce leather that is too thin, but also not too thick leather. Leather that is too thick has to be shaved thinner again and the leather substance of the counterparts is lost when splitting and there is more work and waste in the shaving process. 

The grain split is considered more valuable. The fibre structure is substantially denser in the upper layer of the grain side and is thus tear-resistant. The grain split is referred to as smooth leather when tanned.

After leaving the tannery, the term "grain split" is no longer used. The leather dealer then uses terms such as "smooth leather", "aniline leather", "napa", depending on the leather type. The term "split" no longer appears in connection with the grain side. The drop split with the two rough sides is then no longer referred to as a "flesh split", but only as "split leather", "split" or "suede". In order to make the leathers more intelligible to the layman, this is an important separation of the choice of words in tanneries and in public. This makes it clear that the term "split" always refers to the less stable lower layer of the hide.

In the tannery, the hide is split in large machines while it is still wet. Leather workshops often have smaller splitting machines that cannot split whole hides, but smaller parts.