Wool shrinkage, is it fixable?
Discover why woolen clothes shrink and how to unshrink them
Shrinkage is a very curious and important fact about wool garments' care
We've all been there and we all know how frustrating it can be to wash and dry a wool garment and then find out it's become half the size. And the questions are always the same: Why and how did it shrink? is there a way to unshrink it?
In order to answer these questions, it is very important to understand the wool fiber’s structure. Wool is a protein fiber that has a unique scale structure, naturally crimped and elastic, which means the fibers interlock and hold their shape well. Shrinking happens through the combination of heat and movement, which makes the scales expand and catch on each other, which binds the fibers closer together. The closer the fibers get, the more the wool shrinks. The motion also felts the wool. Felting changes not just the size of the wool but also the texture. Agitation makes the scales on the wool fibers rub together. The more they rub, the closer they lock together, making a dense, fuzzy fabric: felt. Felting shrinks wool down, and once the wool is felted, you cannot un-felt it. In a nutshell, if you avoid heat and vigorous motion during washing and/or drying, you can keep your woolen garments in the right size and shape for ever. But let’s dig deeper into this subject and check all variables.
Let's take a closer look to the structure of wool, compared to other fibers
Animal fibers, like wool, are not smooth. When they are agitated, the scales on the fibers lock together. That’s what causes felting and shrinking. Fibers with a larger quantity of more pronounced scales are more likely to felt and shrink than those with fewer, smaller scales. As you can see the coarse and fine wool are the most likely to felt, but alpaca and cashmere will also felt and shrink if agitated enough.
NOW THAT YOU KNOW EVERYTHING ABOUT WOOL AND ITS STRUCTURE, YOU ARE READY TO UNDERSTAND WHY AND HOW IT CAN SHRINK:
WOOL SHRINKAGE IS AFFECTED BY MANY FACTORS...
Nr. 1
MAYBE IT'S TOO TECHNICAL, BUT THE TYPE OF WOOL YOUR GARMENT IS MADE OF DEFINES ITS SHRINKING RATE
The type of wool changes how much it will shrink. The longer and smoother the wool fiber is, the more heat and agitation it takes to felt and shrink. Merino wool, for example, has fairly long fibers without much natural crimp. So it takes longer to shrink than shetland wool, which has more crimp and shorter fibers. The more a wool fiber naturally curls in on itself, the more it will shrink up. Unfortunately, most of the time, you don't know exaclty what kind of wool was used to make your garment.
Nr. 2
THE WAY YOU WASH YOUR WOOL GARMENT CAN LITERALLY MARK ITS DESTINY...
Water is not the main main problem. That's because wool is made up of a series of interlocking fibers that are held together by scales. These scales help keep moisture away from the wool fiber, which is why wool naturally repels water. BUT If you put wool in hot water, the heat will open up the scales and allow water to penetrate into the fiber. Wool fiber swells when it becomes wet and then contracts when it dries. This is what causes wool to shrink when you wash it in hot water. So If you don’t want it to shrink, just avoid washing it in really hot water. Handwashing in cool or slightly warm water is always recommended for wool garments.
Nr. 3
...NOT TO MENTION THE WAY YOU DRY IT!
Your woolen garment will shrink in the dryer, because it makes it subject heat and friction. Even when you use the low-heat level, the machine does use friction to dry your wool, which can cause pilling and felting. Airdrying wool garments is much better for them, since it prevents shrinking. After washing your wool garment, just make sure that your garment is not dripping wet by gently squeezing the fabric, and then lay it flat on a towel to air dry.
Nr. 4
CHOOSE WISELY, THE DETERGENT YOUR USE CAN PLAY A KEY ROLE IN AVOIDING OR GETTING WOOL SHRINKAGE
An enzyme-free detergent is the only kind of cleanser that is safe for wool. If the cleanser you are using contains enzymes, they will damage the proteins that make up the wool fiber. The more damage to the proteins, the more easily the scales interlock and shrink the fiber.