grain (thing)

Sewing: The direction of the warp threads in woven fabric, parallel to the selvages. In knit fabrics, the grain direction is created by the knitting process, and is parallel to the finished edge.

Paper patterns will indicate the placement of most pieces with a double-headed arrow, which should go along the grain. The only exceptions to this rule are interfacing pieces (since interfacing is generally made using a felting process and has no grain) and pieces to go on the fold. (The fold in a bolt of fabric is always on the grain, so the fold line gives the grain direction.)

If the design on a woven fabric is suitably non-directional, pieces can also be cut with the grain line perpendicular to the selvages, lined up on the weft threads. It is the alignment with the threads that is important, not which type of thread is being aligned to.

Why is the direction of the grain important in sewing?

• In plaids, striped fabrics, and suchlike, the direction of the grain will give the direction of the design in the finished garment, which is sometimes controlled by convention (ever seen a pinstripe suit with horizontal stripes?).
• The grain of fabric also determines its elasticity. Woven fabrics do not stretch when pulled parallel or perpendicular to the grain (unless there is elastic in the weave). However, they do when pulled diagonally.
• Fabric grain affects the way a garment hangs. When its grain is at an angle to gravity, the fabric goes into little ruffles, as each individual thread tries to hang straight down.

Generally, garments are cut "with the grain", meaning the grain is parallel or perpendicular to gravity. Garments that are cut diagonal to the grain are called bias cut.