I press seams open because I could never get the joining seams to "nest". I like the way the finished blocks lay flat and I've had LA'rs tell me they find it easier to quilt.

Now this is a fantastic Tut and really makes a ton of sense. Thanks for reposting, I never saw it the first time

It just depends on the pattern that you are working on. I normally will press to one side. One of the biggest reasons for doing that from what I have heard before is that with open seams you may get bearding from the batting coming through. Also when doing SID you want to do that on the low side close to the seam and you don't have a low side with seams pressed open. Right now I am working on Eleanor Burns day and night pattern and you use both pressed to the side and open. The reason for pressing open some of the seams is so that when you put the whole star block together it helps for get the middle where all the seams meet up to lay flat and form a pinwheel like center for the seams.

I am that lady that the LongArm quilter refered to... I have made many many quilts in my 40+ years of sewing and quilting.
I press my seams open because I like a flat block. In all my years I have not had the seam fail because of it. I tried the press to the dark ..( after an severe encounter with a quilt police) but all to often it resulted in more seams with 4 layers of fabric , where it was impossible to press to the dark and not have this intersection of quadruple layers.... not the flat block I intended.... so I press open..... all the time! When I do quilt my own and use stitch in the ditch ... I also stitch right on the seam , having it open makes it easier to land that stitch right on the seam line.
As for stress on a seam .. I have done my own little lab experiment and sewed a seam on scrap fabric with the same thread for both and pressed both ways ... and tugged directly on the seam ..... guess what ... no difference.
Pressing to the dark , was favored by handquilters, so when they quilted on the light side there were not as many layers to stitch through. Many of the older hand quilted quilts had alot of echo quilting so it was much easier to stitch around the lighter background fabric to make the darker shape have more definition.
As for bearding.. that was an issue prior to bonded fibers and the use of scrim in battings. Bearding can happen through the fabric , not only just the seam.
Each quilter finds what works for them and appeals to their desired outcome. Find what works for you and makes you satisfied and proud you are a quilter.

pressing open is fine for most quilts but if you do stitch in the ditch, you can actually break the thread and weaken the seam. I love patterns that tell you which way to press so there isn't any bulk in the seams but so often I change things up and it doesn't always work.

It's a matter of choice. Most of the time I don't open the seam to press, however I have tried a pattern that called for press seam open and it was very helpful. I am a long armer and it does not bother my long arm at all.

"Seam strength ... is it such an issue now, with most of us machine stitching, with modern threads/fabrics and our ability to adjust stitch length? Perhaps it was more so when the quilts were hand stitched?"

I have been sewing clothing for 40 years, and not once have I ever pressed a seam allowance to one side to make the seam stronger.

I press seams open on about 90% of my quilts.

Depends on the pattern of the blk but mostly to the dark

Your explanation of why the seems should be pressed to one side makes more sense than any I have heard of yet. A good reason to continue to press to one side.

I think it is a matter of preference...if a lot of quilting is to be done on the quilt then a lot of the open seams will be sewn over again, and I would think that would hold it ok. Now, maybe a quilt that was going to be used/washed a lot would benefit from the seams to the side. There are no quilt police in my sewing room so depending on how I feel the day I sew/piece my quilt could experience a little of both!

i press open all the time. have been for years. depends on the design and which will be easier to match and lay flatter. There is no "authorized" way.

when i started quilting i came from garment making. i automatically opened every seam. since the seams are stitched on top of by machine, i think they're strong enough not to ravel even if they should by some chance pop. my clothing seams don't pop and they get a lot more movement so why would my quilt seams pop?

i don't like the way corners bunch up when i press to one side, even if you twist the corners (what's that all about?). i had black and blue thumbs from twisting a 100 x 100 quilt and it was no flatter than opening the seams. it fact, you end up with exactly the same number of thicknesses.

To slow up the wear and tear on my quilting machine I decided to open ALL seams with a wooden dowel. After, the pressing open becomes that much easier and my machine has no problem going over several seams when quilting. It takes a little longer initially, but what a difference when quilting. Love, Joan

I read somewhere that we quilters press to the side rather than an open seam as in clothing sewing because by doing that it keeps the batting from migrating out of the seam-sort of seals it...makes sense. I have always pressed to the dark side(most of the time), unless that would cause bulk, then flip to light, making sure there is no shadow of the dark, and there never has been (so far). As far as pinwheels, and actually meeting of four corners too, I do the little "spin" to lessen the bulk and avoid the "volcano top"...If I recall though, I think those that do miniatures usually press open seams...not enough room for all those side seams, I guess

with modern batting the chances of migrating through the seams is minimal. most quilters today stitch over and across the seams anyway holding the batting in place.

in years past, battings were looser and came apart and migrated more easily and were more of a problem.

like a lot of questionable practices among quilters,this will never have an answer. like washing before cutting. quilters have to try out each method and see what works best for them and go with it.

Yes have read that lately as well and usually seems to much of hassle occ important and then do it.

Pressing seams open makes them not as strong as when pressed to one side.