How to Care for Wool

by Diana Habra. Originally published for the January / February, 2009 issue of Finery.

You have decided to make a beautiful mid-Victorian day dress. You have found the perfect fabric – a plaid wool in lovely shades of gray, lavender, and black. Your pattern is all set and you are ready to cut. But wait! It would be terrible if you went through the trouble to make a beautiful dress only to shrink it later on. To understand how wool will behave when you wash it, you need to understand its structure.

Wool is what grows out of the follicles of certain sheep and in the raw form is called fleece. Wool can also come from certain goats, llamas, and rabbits (think cashmere which comes from a certain type of goat). Wool is not exactly hair but it more closely resembles hair than it does the fur typically seen in other mammals. Wool has scales and is crimped which helps it stay together when it is spun into threads. Finer, softer wool has many crimps per inch whereas coarser wool may have just a few. It is the scales and the crimps that lock and keep wool in the shape that you want it.

When you wash wool, two things happen. The fleece swells with water and the scales stick out. Any agitation during this time will cause the scales to stick together and shrink up the wool. If the wool dries in this condition, the fibers will lock and the garment or fabric will be smaller. It will also be somewhat thicker. You can stretch the wool out while it is wet and unstick some of the scales but you may not be able to get the wool completely back to normal size. Drying the wool with heat (like in a dryer) will also lock some of the fibers together because the scales will shrink rapidly and lock onto other shingles on the fleece creating a thicker, shorter fabric or garment. You can expect 10-25% shrinkage in length and 5-10% in width when you machine wash in hot and machine dry with heat.

So, let me answer some important questions for you now:

Should I wash the wool first? If you want to be able to wash the garment after it is made, then you should pre-wash the wool. Wash it the same way you plan to wash it later on or pre-wash it and then just spot clean it when necessary. Use only detergent in the wash machine. Regular bar soap has a different pH and can make your wool shrink up even more. Pre-washing the wool will also remove any finishing chemicals that may have been used to process the wool into cloth.

What if it shrinks? It *will* shrink and you should be prepared for this. If your wool gets very wet (either in the rain or in the washer), make sure to air dry it and stretch and block it (lay it into shape) while it is still wet. This will allow as few scales as possible to lock together as it dries.

Can I dry clean the wool instead of washing it? Yes, and this is one of the only options that will prevent shrinking. But you must trust your drycleaner not to damage your hand-made garment and all of the details that may be on it (like buttons and ribbons and such). Some people will remove these items before sending a hand-made garment to the drycleaners to ensure they are not damaged.

What if I hand wash it? Will it still shrink? Yes, it will still shrink but not as much as if you washed it in the wash machine. This is a good option if you want to remove the finishing chemicals but not shrink up your wool too much. You can use shampoo as the cleaning agent but do NOT use soap. Try to agitate it as little as possible (you can just dunk it under the shampoo/water mixture and let it soak overnight). And definitely don’t wring the water out after you are done.

Will it have the same drape after I wash it? That depends on what weight the wool was to begin with. If you start with a lightweight wool and wash it, it will probably still have a soft drape. This is especially true if the fibers of the wool are worsted (where only the long strands of fiber are twisted into a compact, fine yarn). If the wool starts out medium or heavy and is a bit fuzzy to begin with, it will get thicker and fuzzier if you machine wash & dry it. The drape will also get stiffer.

Can the wool shrink again even if I pre-wash it? Yes, it can.  So be careful when washing it after the pre-wash. Some people will pre-wash their wool twice to try to make all the shrinking happen in the beginning. When you wash it sequentially, use as little agitation as possible and hang it to air dry if possible. If you use a dryer, even with no heat, you can still cause the fibers to lock together because of the agitation that happens as the dryer turns.

Now you have some choices about how to treat your great new wool fabric before and after you make your lovely new mid-Victorian dress.  And if you plan ahead, you will have a clear plan on how to take care of your wool and keep your new dress in great shape for years!