How to prewash fabric for sewing

June 10, 2021

Why prewash fabric before sewing? When making a project, we presumably want it to wear well and last a long time. Something we also want is to have fabric that lays flat for better quality seams. If your fabric pieces are not lining up because of wrinkling or using different preparations for different pieces of fabric in the same project, that’s a problem. Prewashing the fabric will help it get comfortable, if it is going to shrink, it will shrink now. We want to minimize the changes to the fabric that come with washing, BEFORE we sew with it.


Fabric we’ll be using:

We will be talking about quilters cotton in this post, it is what I’ll be referring to when I say ‘fabric’. I chose to focus on it because it’s easy to find, doesn’t have to be expensive and is great for beginners. Quilters cotton is ideal for quilting (duh) and small projects like aprons, doll accessories, totebags etc.

This kind of fabric is woven, meaning it was created on a type of loom with fibers weaving up and down over each other. If you want to read up on the different fabric types, which will help you decide what to use for future projects, see the guest post about differences in fabric types.

Anything you make with kids or as a beginner should be a woven fabric. Save the stretchy knit, thick, and shiny fabrics for once you have mastered the basics. They even intimidate me on occasion…. If you do not have any fabric on hand, here are some good fabrics to start using. Make sure it is quilters cotton!

Save this post to your favorite sewing board on Pinterest to read later…

To wash or not to wash

Ahhhhh, that new fabric smell. If you’ve been playing with fabric or sewing for any amount of time, you will know what I’m talking about. When fabric is manufactured, it has a chemical applied to it before being wound onto bolts. The chemical is called ‘sizing’ and it gives the fabric that crisp feeling, super smooth feel and doesn’t allow it to wrinkle easily. It’s dreamy, right? It reminds me of starching a fabric while ironing. But, we don’t want the sizing in projects that are going to be washed when used later on.

If you are making something that will never be washed, you could technically skip the prewash step. But I think it is a good habit to get into. If the item is a gift and you do not include a care tag, it might get washed. It might be washed properly or it might not be. Always include a care tag telling the gift recipient how to care for the items. Even better if it is permanently attached to the item.

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Prewashing fabric

Prepping to prewash fabric starts before putting the fabric in the machine. It starts when out fabric shopping. Remember to read the end of the cardboard bolt for laundering instructions. If it is something outside of typical directions, take a photo with your phone to remember. (I consider typical to be wash cold, dry on low, just for reference)

Of course the only bolt I have has different instructions, line dry…

laundering instructions for prewashing fabric

● Getting fabric from the store, the employee will likely cut the fabric. On occasion, the store will make a small little snip with scissors and then rip the fabric the rest of the way. Don’t panic, when using woven fabrics, you can make that snip and pull the pieces apart to get a straight line. Due to the nature of the woven fabric, the rip line will be a very accurate, so don’t discount that technique. Both methods will still produce a lot of threads and tangle in the wash.

● Open up the fabric all the way, don’t leave any folds. Even if you have a lot of yardage, make sure it is open ALL THE WAY!

● Launder according to the directions on the fabric bolt.

Not all fabric should be washed! Not all fabrics should be dried. Pay close attention to the laundering instructions.

● Some of the more saturated color fabrics can bleed when washing. Wash like colors together. If you have a dark red and a light pink, you’ll want to wash them separately. Higher quality fabrics are less likely to bleed, but don’t assume it won’t. You know what assuming means, right?? I like these color catcher sheets JUST IN CASE, even when I think it should be, you would be surprised what shows up on them after the first wash. I would rather be more cautious and not risk ruining the fabric I just bought!

If your final project doesn’t allow for washing it the same way as the fabric laundering instructions say, you may need to make some adjustments.

Examples: if you intend on adding little flourishes that are not washable, you won’t be able to wash the whole thing, and if you can’t wash it, it shouldn’t be something that is used daily. Ewwww… gross.

If you prewashed red fabric and it is still bleeding, making a quilt with that red fabric will still bleed on any lighter fabric when sewn into a quilt.

All of these little details need to be figured out now, so that you are not surprised later.

● When the fabric is done washing in the washing machine, don’t be alarmed if the fabric is all in tangles and knots when you pull it out. All the threads that were on the edge have now dislodged and tangled around everything else. This is a place where I find the most wrinkles are formed.

knots formed with fabric threads
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Options for ironing

Note: I have two irons (see my favorite things for sewing post). One for nice stuff and one for not so nice stuff, like fusing interfacing or something that I just don’t care about. I never put water in the nice one, I like staying on the safe side for things I have to pay for… If I forget to take the water out it will rust. I’m so forgetful, I’ve learned my lesson the hard way.

● Pull the fabric out of the dryer when it’s still slightly damp. Iron it using the correct setting on the iron for the type of fabric you are using. This is what I try to do, I figure the wrinkles aren’t as set in the fabric when it gets dried all the way. But I forget to set a timer and usually end up doing the next option.

● Dry all the way in the dryer, spritz with water and iron.

● Dry all the way in the dryer, then use steam function on iron and iron.

When done prewashing and drying, you will get a better sense of the weight and quality of the cotton. Take for example, this purple fabric has a thicker weight. I am having a hard time differentiating between the prewashed and straight off the bolt. They are identical except for the amount of thread pulling away from the edge in the prewashed sample, the top fabric layer of the image below.

BUT FIRST, DO NOT UNDER ANY CIRCUMSTANCES cut the pieces out according to the pattern and THEN wash them. Just don’t. They will fray and you will lose surface area, the edges won’t line up and it’ll just be a miserable mess. I’d rather you sew them together and then wash. That would definitely have a better outcome. See below for photo evidence.

See how the green fabric below has shed more threads at the edge? (The top layer is the prewashed and the lower layer is straight from the store.) It is also a thinner fabric than the purple variety. I don’t know if you can see a difference between the two, but in real life I can see a very slight color change on the prewashed fabric. It is a smidge more dull, just barely but I can see it. Washing the sizing out and the slight agitation of the washing machine takes away the luster of the unwashed fabric.

This is a VERY SLIGHT difference. Having the project wash better after construction is well worth losing that luster and crispness before sewing.

I don’t know if it’s just me or what, but every once in a while I get a fabric that is hard to get super flat. Not sure my iron gets as hot as that fabric needs to get perfectly flat. I’d also be more scared than I already am of the iron if it got any hotter!

A long time ago I used starch, but as I like to take the quick route, I’ve skipped it since then. Prewashed fabric is just not as stiff when you pick it up and crisp to line up pieces to sew together. I have not noticed any kind of difference when the project is done but it does make lining them up easier when they are all nice and crisp with starch… ahhhh.

I’m not into making more work than is necessary, have you noticed?

After prewashing fabric, you are going to most likely need to straighten the edge. Read here about how to straighten the fabric edge.

THE POINT HERE: You want to wash/launder the new fabric the same way that you plan on washing the final project.

What if I don’t prewash and I should have?

If you skip the step of prewashing the separate fabrics (assuming there is more than one fabric in your project), then sew them all together to wash… There is the possibility that you will have a wrinkly mess. Different fabrics shrink at different rates. Even 100% cotton varieties have variances between brands and weights. So if I use a super shrinkable fabric next to one that doesn’t shrink much, the one that doesn’t shrink much will buckle and be wavy/wrinkly because it is sewn to the one that does shrink.

For other projects using other types of fabrics, you will want to do the same thing. All the fabrics should have the same laundering instructions AND the fabric prewash is the same procedure as after care of the garment. I’m repeating it so it gets into your head.

Learning that you messed up a simple thing such as checking the laundering instructions after taking days/weeks/months to make something is a sure way to kill the creative spirit. Just sayin’

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