Wool Shrinkage during Jacket Construction

Front lapels are joined into the shoulder seams; an unusual design feature that is easy to sew

I've been wanting a red wool blazer for a long time: red provides a boost to many neutral trousers in my wardrobe.  It also makes me feel energetic and young.  The pattern is #119 from the July 2010 issue of Burda Style.  The wool was purchased at Mood Fabrics last winter.  It has a three dimensional twill weave as shown below.

Twill weave

As usual, I steamed and pressed the wool before cutting out the garment panels.  Then I applied fusi-knit fusible interfacing, my go-to interfacing for at least fifteen years, to all garment panels.  When I laid the pattern pieces on top of the fused panels in preparation for marking, I noticed the panels had shrunk 1/2" in length.  Below is a photo of an under sleeve.  Note the shrinkage in the hem allowance.

1/2" shrinkage in length

Fortunately I did not loose circumference.  I took the 1/2" shrinkage from the garment hem allowances and marked the original finished hem length.

Use tracing paper to mark original hem length

I thread traced the hem allowances with silk thread so the hem lines were visible on the right side of the garment panels.

Sleeve with 1 1/2" hem allowance instead of 2" due to shrinkage

My problems with the garment body were solved, but I will return to discussion of the sleeve length soon.

Below are the two sleeves.  The vertical seams have been stitched.  The seam allowances have been pressed open on the left sleeve.  The seam allowances have been pressed and hand catch-stitched to the interfacing on the right sleeve.  It took maybe 1 1/2 - 2 hours to catch stitch all jacket vertical seam allowances.  The benefits are (1) seam allowances that lay flat after many wearings, and (2) less friction between the garment and the wearer's body.

Seam allowances catch-stitched on right side

Back to the sleeves.  I must have made an error when I analyzed the fit of the pattern in muslin because the sleeves of the final garment were way too short.  I took 1" of additional length from the 1 1/2" hem allowance which was originally 2".  A bias cut rectangle 2 1/2" x 11" was seamed to the cuff so I would have a proper 2" hem allowance.

Seam a hem facing to the sleeve cuffs

The photo below shows the sleeve cuff with a 2" hem allowance.  The jacket is saved.  I used to get upset at these occasional sewing errors, but I have learned to accept them.  I think they are inevitable no matter how long a person has sewn because fabrics behave differently, equipment malfunctions, tastes change, etc.

I still don't understand why the wool shrunk so much in length.  The wool is not a loose weave, however it is also not tightly woven like traditional wool suiting fabrics.  Next time I fuse interfacing to a wool fabric, I might add 1/2" to the hem allowance for insurance.  Have any of you had this problem recently?

A rare "selfie"

I like this pattern enough to make another jacket or two.  My plan is to experiment with the lapels and maybe add pockets.