So I stopped prewashing.
Recently, though, another friend emphasized that she always prewashes her quilting fabrics—argh! I decided to look into it.
It seems that, beyond the shrinkage question, there is some concern about fabric dyes bleeding out into lighter colors during the first wash. If that bleeding happens after the quilt is already together, all your hard work is ruined.
There is also the question of different fabrics shrinking in different degrees.
This quilt was started so long ago that I had prewashed most of the fabrics. Only the last few squares were made with fabric that I didn't bother to wash. Perhaps a goofy, misshapen quilt is in the future but at this point, if it's a finished quilt of any kind, I'll be happy.
My border fabrics have been sitting around long enough that they were also prewashed, except for the yellow. So I washed and dried that to match.
And then, doing some more reading, decided to starch the fabric to put back some of the stiffness that washing took away. I learned at this point that starch, being edible, will attract silverfish and other critters. A tradeoff that is mitigated by, yes, washing the quilt after it's been pieced.
On the plus side, it is easy to make homemade spray starch. There are many recipes. I chose the simplest, which made just enough to fill the spray bottle I had on hand. For future reference, I listed the ingredients on the side of the bottle. Some day I may make a cute little recipe label, but this is adequate for now.
Homemade Fabric Starch
Dissolve 1 Tbs. cornstarch in 1 pt. cool water. Bring to a boil, stirring or whisking to dissolve cornstarch completely. Let cool, then add 2-3 drops lavender essential oil and pour into a spray bottle.You can add more cornstarch if you want a stiffer fabric. The original recipe called for lemon juice, which I changed to lavender, as lavender is a natural insect repellent. Maybe this will compensate for any starch that happens to remain after washing.
There are boiled and non-boiled versions. Being lazy and impatient, I made a non-boiled version first, and it worked nicely the first day with a little shaking now and then.
However, after it sat overnight, the cornstarch was a solid mass on the bottom of the bottle. It struck me that I had just made a bottle of Oobleck! Trying to loosen the cornstarch, I ended up tapping the bottle so hard that the plastic cracked.
I decided at that point to boil the rest and sure enough, the cornstarch dissolved completely without any subsequent settling out. This is the recipe I would recommend and will use from now on. Boiling and cooling didn't add that much time in the end.
So there you have it:
Step One: Prewash fabric to shrink and remove excess dye.
Step Two: Spray with homemade starch during ironing to put back sizing elements lost during washing.
Step Three: Quilt as usual.
Step Four: Wash quilt to remove starch from Step Two so quilt won't be attractive to bugs.
Or, if you love the simple, unfussy life: don't prewash, assume that shrinkage will only emphasize the stitches and enhance the loveliness of the quilt, and use this at first washing.