Washing fabric before sewing: yes, no, maybe?

Why pre-wash garment fabrics?

There are various reasons to pre-wash garment fabrics one or more times.

Pre-washing fabrics removes chemicals and pollutants

Fabrics often travel long distances on their way from production to your sewing table. To ensure they aren't attacked by pests during transit, don't develop mold, or suffer color defects due to light exposure, they are pre-treated.

The chemicals, dyes, sizing agents, anti-mold agents, or insecticides present in the fabric can have unpleasant side effects if you don't wash them out before wearing.

I therefore recommend that you wash garment fabrics before sewing to remove any chemical residues used during the manufacturing process. This is especially important if the clothing is made from delicate materials like cotton or silk, as these materials tend to lose color and shape during the first wash. Even with garments made from synthetic materials, pre-washing can help reduce residual pollutants.

Pollutants from the fabric can enter the body through the skin. Especially when the skin is particularly thin, delicate, and sensitive, pollutants and chemicals can trigger allergic reactions that manifest as itching, bumps, or rashes.

For clothing worn directly against the skin, pre-washing is a good idea. This is especially true for clothing for babies and children, as their protective skin barrier is still developing.

Pre-washing linen or woven fabrics has another positive effect: the fibers become softer and more supple during washing. You may be familiar with that slight prickling sensation that new linen fabric sometimes has. Those are the (flax) fibers protruding from the weave. After several washes, these fibers eventually break down, and the fabric becomes significantly softer.

Pre-washing fabrics for bags and accessories

Bags can be sewn from many different fabrics and materials. If your bag is meant to be washable, it must be sewn from a washable material. This is important for items like shopping bags, which come into contact with groceries and potentially liquids. But many other types of bags also need to withstand a quick trip through the washing machine.

Woven fabrics like cotton poplin, canvas, coated fabrics, decorative fabrics, or linen are inherently washable. It always depends on the manufacturer's care instructions. Reputable shops include these instructions in the product description. I often recommend pre-washing, while my colleague Simone points out that in many cases, a thorough steaming is sufficient. She also advises looking for the term "washed" – as those fabrics do not require a prior machine wash.

Bag materials like faux leather, cork, felt, or textile paper do not necessarily need to be pre-washed because they do not shrink.

How to prepare fabrics for washing

To ensure nothing goes wrong during the pre-wash, you can prepare your fabrics before they go into the machine. Let’s look at how it works:

• Only wash similar colors and color depths together: Dark denim and light blue linen should not be washed together because the denim can bleed and stain the lighter fabric.
• Do not put too much fabric in the washing machine: This can cause light-colored creases and streaks that are difficult or impossible to remove later.
• Finish the fabric edges beforehand with an overlocker or a zigzag stitch: This prevents the fabric edges from fraying.
• Fold the fabric along the grain and serge the raw edges right sides together: This protects the colors and stabilizes the fabric; it won't twist as much and is easier to dry and iron; plus, this preserves the fabric fold.
• Place particularly delicate fabrics in an old pillowcase before washing: This keeps them from twisting and tangling in the washing machine.

What happens when you pre-wash fabrics?

Washing fabrics before sewing has many positive effects:

• The fibers tighten and become softer.
• Chemical residues, sizing agents, and pollutants are washed out.
• The fabric shrinks.
• And reaches its final size.
• Color residues are removed.
• Dirt is removed.

Additionally, washing can enhance desired fabric properties. Boiled wool, for example, becomes denser and more stable after pre-washing. SnapPap gets a cool distressed look. Corduroy does too.

Which fabrics do not need to be pre-washed?

Any fabric that does not inherently shrink does not need to be pre-washed if the only goal is preventing shrinkage. However, to remove pollutants, it is still recommended, provided the fabric is washable.

Fabrics that do not shrink in the first wash include, for example:

• Faux leather
• Softshell
• Rain jacket fabrics
• Nylon fabrics
• Polyester
• Vinyl
• Cork fabric
• Sewing paper like Tyvek

READING TIP: Which fabric for what?

What happens during shrinkage?

Something magical happens during the first few washes: the fabric shrinks. It no longer looks like it did right after purchase; instead, it pulls together in length, width, or both directions. This shrinkage, sometimes also called "draw-in," can amount to 30% or more with natural fibers.

The fibers densify and shorten, and the fabric becomes firmer and more stable. Shrinking is, by the way, not a quality defect but simply part of the process. Important: Plan for shrinkage when buying fabric and buy extra yardage for cotton wovens, muslin, boiled wool, linen, etc. If you have too much fabric left over, you can find great projects on our site for using up fabric scraps.

What should you keep in mind when drying fabrics?

This depends on the manufacturer's care instructions. I recommend following them so that your fabric stays beautiful. It can be helpful to note the washing instructions in your sewing diary (for example, the SewSimple Sewing Journal^*).

If the finished garment will be tumble-dried in the future, then you should also do that during the first wash. Because many fabrics shrink again when dried.

With fabrics that are air-dried, clothes pegs can leave pressure marks that are difficult to remove later. Therefore, it is often better to simply drape the serged fabric pieces loosely over the line without using pegs.

It also helps to lay a towel underneath and/or, if you must use clothes pegs, to clip a doubled-over piece of terry cloth or a cleaning rag between the peg and the fabric. This can help you avoid pressure marks.

What do the care instructions actually mean?

Are the many care symbols confusing you? No wonder! To make it easier for you, I have prepared an overview here:

Does ironing replace pre-washing fabrics?

Ironing cannot really be a true substitute for pre-washing. Ironing does not remove chemicals and sizing agents. And naturally, removing color residues does not work through ironing either.

That is why I think it is important to point out that fabrics worn against the body should be washed beforehand.

If, on the other hand, you want to create a bag, a pouch, or an accessory, it is often sufficient to steam-press the fabric thoroughly. The fabric will also shrink slightly and the fibers will smooth out during this process.

Of course, there are exceptions: if you want to work with muslin (or another textured fabric), you should definitely avoid ironing it. If you iron muslin, you smooth it out. If it is then cut, it will indeed retain this smooth surface. But with the first wash, it springs back into its crinkle. Result: The garment is too tight.

READING TIP: Sewing muslin – everything you need to know

Washing cotton woven fabric

Cotton fabrics with prints can be washed in the washing machine at moderate heat (30-40°C). Use a mild detergent and choose a delicate cycle, if available. Cotton fabrics can (depending on manufacturer instructions) also be tumble dried, but they should not be ironed too hot to avoid deformation.

To ensure the fabric is nice and stable again afterward, for example when sewing bags, you can treat it with spray starch. This is always worthwhile when the project requires a firm fabric. Starching makes the fabric edges stable and prevents them from stretching during sewing (yes, this also happens with woven fabrics!).

When spinning, you should avoid high spin speeds so that the fabric does not get creases. For most cotton woven fabrics, 600 to 800 rpm is fine.

Pure cotton woven fabric can certainly be ironed with high heat and steam.

A little tip: Many quilters swear by not washing their fabric before sewing. Especially for meticulous paper piecing or fiddly quilt blocks (do read our posts about quilting and about patchwork!), fabrics are often used exactly as they were purchased.

Reading tip: Sewing cotton fabrics

Washing jersey and sweat fabric before sewing

Sweat fabric and jersey can generally be washed in the washing machine at low to moderate heat (30-40°C). Use a mild detergent and choose a delicate cycle if your machine has one. A quick wash at a low temperature is also a good idea. Make sure the fabric is not spun too intensely. And here again: follow the manufacturer's care instructions.

It is also important not to iron sweat fabric and jersey too hot to avoid deformation. It is recommended to turn the items inside out and iron them at low heat. And of course, beforehand: sew the fabric edges together right sides facing using an overlocker.

This overlock seam is simply cut off after ironing.

By the way, it is sometimes also recommended not to tumble dry sweat fabric and jersey, but to dry them on a clothesline or a drying rack. Fold it carefully so that it does not warp due to its own weight.

Reading tip: Sewing jersey with a sewing machine

Do you have to wash batting before sewing?

Let's talk about patchwork batting: Batting should generally be washed before sewing to avoid potential shrinkage or color changes before the final project. It is important to follow the manufacturer's washing instructions, as directions can vary depending on the type of batting. Some batting fabrics can be washed in the washing machine at low heat, while others should be hand-washed or professionally cleaned. It is also important to note that batting should not be tumble-dried, but dried flat or on a clothesline.

Reading tip: Fabrics and batting for patchwork

However, when we talk about fusible interfacings like Vlieseline H250, S302, H630, or similar, things are different: These interfacings do not shrink, or barely shrink, during washing. You can use them unwashed. And I even advise it, because a wash cycle can damage the structure of the interfacings. Many of the fusible interfacings only become truly stable once they have been firmly bonded to a fabric with heat and have cooled down.

How are boiled wool and wool fabrics washed before sewing?

As a self-confessed fan of boiled wool (do you know the pattern for our LOVIS jacket? It is fantastic for working with boiled wool!), I have a lot of experience with this. Most people advise against washing boiled wool before sewing because it shrinks.

My TIP: Precisely for that reason, you should wash boiled wool before sewing. The fabric becomes much denser, softer, and repels moisture and wind better. After the first wash, you are truly holding a completely different fabric in your hands. And you can be sure that your finished jacket won't shrink during the first wash. Because wool has many small, hooked fibers. During washing (just like during the felting process!), the fibers tangle, connect, and ensure that the knit becomes firm and stable.

Wool fabrics should generally be hand-washed or professionally cleaned to preserve the natural properties of the wool and avoid deformation. If you want to wash your wool fabrics in the washing machine, it is important that you put them in a laundry bag beforehand so they do not tangle or deform. Use a wool detergent or a mild shampoo and select a wool wash cycle. Many wool fabrics also like being hand-washed.

It is also important that wool fabrics should not be tumble-dried, but allowed to dry flat or on a clothesline, and ironed, if at all, only at mild heat.

Reading tip: Sewing thick fabrics

Washing velvet before sewing

Velvet is a fabric made from cotton, silk, linen, or synthetic fibers and has a particularly soft, fluffy surface.

It is often used for furniture, clothing, and accessories. Velvet should not be washed in the washing machine, as it can cause permanent damage. Therefore, velvet is also not washed before sewing.

Instead, it is recommended to have the velvet professionally cleaned or to carefully wipe it by hand with a damp cloth and mild detergent. It is important that the velvet does not get wet and that water does not penetrate the fabric.

Ironing is also a no-go for most velvet fabrics, as this can damage the fibers.

It is a bit different for panne velvet, stretch velvet, or stretch velour. They can usually be washed at 30 degrees and ironed inside out at mild heat.

Washing silk before sewing

Silk is a natural protein fiber material, produced mainly by silkworm caterpillars. It is known for its smooth texture and sheen. Silk should be washed at low temperature and with a mild detergent by hand or on a delicate cycle. It is important to follow the washing instructions on the label and to separate dark colors during washing. It is best not to wring out the silk, but to squeeze it gently to remove excess water.

To dry, silk fabrics should be spread out flat or hung on a drying rack. If it is ironed at all, only at a very mild temperature.

How do you pre-wash synthetic fabrics?

Synthetic fiber fabrics are synthetic materials made from chemical substances. They include materials such as polyester, nylon, acrylic, and polyacrylic. They are known for their durability, dimensional stability, and resistance to stains and dirt.

Most synthetic fabrics do not shrink. However, because there are so many different types of synthetic fibers, my general recommendation at this point is to follow the manufacturer's care instructions. Most synthetic fibers tolerate machine washing well but should only be ironed at a mild temperature, if at all.

Pre-washing linen

Linen is a natural fiber material derived from the bark of the flax plant.

It is known for its high durability, breathability, and moisture absorption. It can usually be machine washed, but it is important to follow the care instructions on the label. Linen shrinks significantly during the first wash, which is why it is extremely important to pre-wash the fabric. Not to mention that the fabric gradually becomes much softer with every wash.

Simone's tip: Finish the edges of the linen fabric before washing. Use either an overlock machine or the zigzag stitch on your home sewing machine. During the wash cycle, threads can pull and become tangled with each other. The fabric could come out of the machine as a tangled mess.

Use a detergent that does not bleach the fabric. Dark colors should definitely be washed separately. It is best to air dry linen on a line rather than putting it in the dryer, as it can warp during the drying process. And of course, because the fabric can fray very easily, the edges should be finished before it goes into the machine.

When ironing, you don't need to hold back with most linen fabrics: linen usually only becomes truly smooth when ironed at a high temperature.

Recommended reading: Sewing with linen fabric

Pre-washing corduroy

Corduroy is a sturdy, woven material made from cotton, wool, or synthetic fibers. It is characterized by its signature parallel ribs, which give the fabric a distinctive texture. Corduroy is sometimes also called "Manchester" in German, as it was likely first industrially produced there.

Corduroy fabric can usually be machine washed, but it is important to follow the care instructions on the label. Use an all-purpose detergent and wash the corduroy at a low to medium temperature.

Dry the corduroy in the dryer on a low to medium setting or on a drying rack. If necessary, it can be ironed at a mild to medium temperature.

Wash denim before sewing

Jeans is actually the name of the final product. The proper name of the fabric we are talking about here is: denim.

Denim fabric is typically indigo blue, wonderfully robust, and very durable. It is usually used to make pants, but jackets, skirts, and other clothing items can also be made from denim. Manufacturers now offer not just denim for pants, but also shirt-weight, decorative, or stretch denim in many varieties and colors. If your denim fabric is already pre-washed, you don't need to expect a significant amount of shrinkage. However, denim that has not been pre-washed will shrink considerably during the first few washes. You should take this into account in your fabric calculations.

Denim should normally be machine washed, turned inside out, at a moderate temperature. It is also recommended to use a special detergent for denim. To maintain its color and shape, it should not be washed too often and should be air dried. If necessary, it can be ironed, but at a low temperature and on the wrong side.

Recommended reading: New things from old jeans

Wash viscose before sewing

Viscose (rayon) is a chemical fiber made from wood pulp. In this context, "chemical" means that while the base material is natural, it is chemically broken down into its individual components and spun into threads. There are different processing methods for this smooth, cool, and slightly slippery material.

It is popular as a woven fabric, as viscose jersey, or as a blend with cotton or linen. In a blend, this great fabric reveals its positive properties—making linen, for example, less prone to wrinkling, softer, and much more comfortable to wear (and iron).

Viscose should always be washed at a mild temperature (30–40°C / 85–105°F) and ironed according to the manufacturer's instructions. Because viscose fabrics also shrink, pre-washing is definitely advisable.

Recommended reading: Sewing with viscose and other slippery fabrics

Wash ribbing fabrics before sewing

Ribbing fabrics usually consist of a blend of cotton and elastane. They are knitted on circular knitting machines, so they are a knit fabric. Due to this specific production method, they are usually sold as tubular fabric.

There are smooth types of ribbing, but also ribbed varieties. Ribbing can also vary in thickness.

What they all have in common is the task of providing clothing items with a hem that fits snugly against the body. This is why ribbing must be elastic. The special structure of the fabric ensures that the ribbing stretches when you pull your head through the neckline. Afterward, the ribbing fabric returns to its original shape thanks to its ribbed structure and elastane content, lying snugly against the neckline.

Ribbing fabrics should be washed at 30–40°C (85–105°F) before processing so that they can shrink. They should be hung to dry. You can skip the subsequent ironing, however: ribbing fabrics can lose their shape due to the heat of the iron. It is better to gently smooth them into shape while they are still damp.

Recommended reading: Sewing on ribbing

What does "dry cleaning" actually mean?

....and why is this washing technique important for some fabrics?