Reading a quilt book, Ultimate Book of Quilt Block Patterns, by Judy Martin and found an answer that makes sense.

"Generally, in patchwork, seam allowances are pressed to one side rather than being pressed open. This keeps the batting from seeping through the spaces between the stitches. It also forms ridges that will help you align seams perfectly at joints."

Have seen this especially with the polyester battings. :D

The batting seeping makes sense but I have never had the ridges guarantee perfectly matched seams. :D

Most batting no longer beards, but nested seams definitely are an aid in matching seams and pressing to one side is almost an essential for stitching in the ditch.

After years of sewing, since 1960's, Marsha Marsha style skirts and vests, I was schooled in open seams.

For Quilting I was schooled in side of darkest fabric but did not know why.

Thanks for connecting the dots! :)

Kris

I personally set to one side as to align up the seams..and, it works like a dream. I normally press to the dark as not to see the seam thru lighter fabric. When I hand piece, I do leave the seams open...as it is easier to get thru:)Skeat

i do which ever works best for the project. large blocks the seams can be pressed to one side but if you're working on 4 inch blocks with pieces that measure 1/4 square there isn't room to press to one side without creating a tremendous bulk issue.

I dislike pressing seams open, since I usually press or steam my fingers as well. Also, if the seams are pressed open, you can't do stitch in the ditch, since you don't want thread on thread without any fabric holding anything in place

I press mine to one side and the butting one seam up to another usually works for me.

Like you I have always sewn clothes. Never could figure out why we didn't press the seams open on a quilt, this makes sense now. You gals that do the tiny stuff have a special talent and those tiny projects are wonderful. Me thinks I like the pressing to one side, all my blocks are BIG :D

I press to the side but if it creates to much bulk then I press it open. The pressing to the side and matching seams is easier for me, I can feel it when they lock together. The open seam matching my pins seem to move and I have to pin and check, pin and check. I generally press to dark side when pressing to the side.
I also have that book and I love it.
BillsBonBon