Unsanforized denim, also known as “loomstate” or “shrink-to-fit” denim, is made from cloth that has not been through the sanforization process. In sanforization, the fabric is stretched, fixed and shrunk in length at the mill in order to reduce the amount of shrinkage that can occur after the first wash. Since unsanforized denim does not go through this process, it is expected to shrink up to 10% after the first soak.
It is common knowledge to give your unsanforized denim an initial soak prior to your first wear in order to ensure the right fit. When purchasing unsanforized denim, it is wise to size a couple sizes up in order to compensate for the amount of shrinking that could potentially happen.
When soaking your denim, there are two main things that will affect the amount of shrinkage that could happen:
Unsanforized (shrink to fit) denim does not go through a shrinking process, meaning you’ll have to size up appropriately to compensate for the amount of shrinkage that will happen after the first wash.
Jeans made from sanforized denim go through the process of pre-shrinking at the mill, meaning you don’t have to size up when buying your jeans. Many people prefer sanforized jeans for this reason exactly, and they feel more comfortable buying jeans they know will fit.
Undergoing the process of sanforization not only affects the sizing of your denim, but the texture of it as well. This process of stretching and shrinking will lead to smoother looking denim while will lack some of its off-the-loom characteristics.
Unsanforized denim retains its rougher characteristics, as it remains unaltered until the day it is purchased.