We Washed 5 Battings: Measured Shrinkage and Loft Loss

A friend finished a queen-size sampler, quilted it in a generous 9" grid because she was tired, washed it, and pulled out a quilt with soft bubbles sagging between the lines and two seams that had crept loose inside the batting. The packaging said "soft" and "traditional". What it also said, in small print on the back, was that the batting needed quilting every 4". She had missed it, and one wash was all it took to make that visible.

So we measured instead of guessing. Five 18" squares — 100% cotton, polyester, 80/20 blend, wool, and a bamboo-cotton blend — each layered with the same prewashed quilting cotton, quilted in an identical 4" grid with a walking foot, then washed warm and tumble dried on medium in one load together. Everything below is what the ruler said afterwards, alongside the maximum quilting distance each manufacturer actually allows.

1. Cotton: 3.5% shrinkage and a crinkle you cannot undo

The cotton swatch measured 17 3/8" across the centre after drying, down from a true 18". That is roughly 3.5%, and on a 90" quilt it works out to just over three inches lost in each direction. The crinkle was immediate and heavy — the puckered, antique look people either love or find fussy.

Loft barely changed. Cotton starts flat, around 1/8" measured at a folded edge, and it stayed flat; what changed was the surface, which went from smooth to textured because the batting pulled in while the quilted fabric had nowhere to go but up.

What the spacing limit means in practice

Most dense cottons allow quilting up to 8" apart, and a few scrim-free ones drop to 2" or 4" because there is nothing holding the fibres together between stitching lines. Check the wrapper, not the shop shelf label. A needle-punched cotton such as Mid Loft 100% Cotton Batting Quilter's Dream gives you room to space lines out while still shrinking enough to crinkle.

2. Polyester: 0.3% shrinkage, and the loft survives the dryer

Polyester came out at 17 15/16" — measurable only because we were looking for it. Over a whole bed quilt that is well under half an inch, which means borders stay the length you cut them and a pieced grid stays square after washing.

It was also the only swatch that kept its full height. Loft measured 3/16" before and after, so the quilting lines still read as sculpted channels rather than flattened creases.

The trade-off is drape. Polyester springs back rather than folding softly, so a poly quilt sits on a bed beautifully and wraps around a person less willingly. It is the safer choice for anything that gets washed constantly, which is the same reasoning behind batting choices that survive weekly washing on a family blanket.

3. The 80/20 blend: 2.1%, the compromise that actually behaves like one

The blend finished at 17 5/8", a shade over 2%. That is roughly two thirds of the cotton figure — enough crinkle to soften the surface, not enough to tug a long straight border into a wave.

Loft held better than cotton and less than poly, which is the honest summary of every 80/20 property we measured. Most blends allow quilting up to 8" or 10" apart, so they suit someone whose free-motion quilting — stitching with the feed dogs lowered, moving the quilt by hand — is still uneven in density.

Does prewashing the batting remove the crinkle?

Mostly, yes. Prewashing cotton or a blend takes out the majority of the shrinkage, and with it the puckered look, leaving a flatter and more modern finish. If you do it, soak rather than agitate, and dry flat — a wet batting in a spin cycle stretches and tears.

If you want to see how a blend behaves over years rather than one cycle, the long-run comparison of polyester, cotton and 80/20 wadding across twenty washes is the useful follow-up. Our shelf choice for this weight is the Mid Loft 80% Cotton & 20% Poly Batting Quilter's Dream.

4. Wool: 1.4% shrinkage, the highest loft, the narrowest margin for error

Wool measured 17 3/4" after a warm wash, about 1.4%, which surprises people who expect wool to shrink hardest. It shrinks modestly when it is treated gently and catastrophically when it is not, and the difference is water temperature and agitation, not the fibre.

It also kept the most height of any swatch: 1/4" loft before, a hair under that after. Quilting lines sat in deep valleys, which is why wool is the standard choice when someone wants hand quilting or feather designs to show from across a room.

Spacing is the catch. Many wool battings cap quilting at 4", a few stretch to 6", and that limit is real because wool migrates through fabric — a phenomenon called bearding — when it is left unsupported.

5. Bamboo blend: 2.8% shrinkage and the softest hand of the five

Our bamboo-cotton swatch came out at 17 1/2", about 2.8%, behaving much closer to cotton than to poly. Loft dropped visibly, from 1/8" to noticeably thinner, and the swatch ended up the floppiest of the group.

That floppiness is the point. Bamboo blends drape like a good bedsheet, which suits throws, wall hangings that need to hang flat, and anything a person will wrap around themselves. It is a poor choice when you want a quilt to sit up and hold shape.

Most bamboo blends allow around 8" quilting spacing. If you are choosing for a nursery, the fibre-safety questions matter more than the shrinkage figure — that is the ground covered in this guide to what makes batting safe and soft for a baby quilt.

Common quilt batting mistakes, and the fix for each

Cutting the batting the same size as the quilt top. Fix: cut it at least 4" larger on every side. Basting shifts layers, and quilting pushes fabric outward from the centre, so a flush edge always ends short before you get to the binding.

Ignoring the maximum quilting distance printed on the wrapper. Fix: read it before you plan the quilting design, not after. Spacing your lines wider than the stated limit is what turns batting into lumps inside a washed quilt, and no amount of careful stitching prevents it.

Assuming loft equals warmth. Fix: judge warmth by fibre, not thickness — a flat wool batting outperforms a thicker polyester for heat, while polyester wins on bulk. Loft decides how the quilting looks; fibre decides how the quilt feels.

Pushing high-loft batting through a domestic machine. Fix: match the batting to the throat space you actually have. A lower-loft blend made for machine quilting, like the Mid Loft 70% Cotton & 30% Poly Batting for Machines Quilter’s Dream, rolls under a walking foot without fighting you.

Trimming the batting flush before deciding how you will bind. Fix: decide the binding method first. If you plan to fold the backing forward over the edge, the batting has to stop at the finished quilt line while the backing extends past it, and this short demonstration shows exactly how that fold is formed.

One more thing worth doing once: make your own 18" test swatch from whatever batting you have left over, wash it with your normal laundry, and write the before-and-after measurements on the selvage edge in permanent pen. Ten minutes of sewing tells you more about how that specific batting behaves in your machine and your dryer than any comparison chart, including this one.

Closing Thoughts

Five swatches, one cycle, one ruler — these figures are indicative rather than laboratory-grade, and your water temperature and dryer will shift them a little. What they do settle is the ranking, and the ranking holds: cotton shrinks most, polyester least, blends sit where you would expect, and wool behaves well only when handled well.

Choose on two numbers instead of two adjectives. How much shrinkage you want in the finished surface, and how far apart you are honestly going to quilt.

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