There are some yarns, like hand dyed or specially textured ones, that are supposed to appear irregular or random when you knit them but sometimes don’t! When the color or texture of a yarn inadvertently concentrates in certain parts of the fabric and forms an unwanted pattern, we call it “pooling.”
Pooling usually happens when you’ve hit upon a stitch count and gauge that put the patterning in the yarn into a rhythm with itself. It’s like your knitting is in resonance with the ebbs and flows of the yarn. Sounds nice, but it doesn’t always look nice!
To avoid pooling, simply alternate two skeins of yarn every row or even every two rows. If you’re working in the round, do the same, and follow this tutorial for tips on how to carry the yarn up the inside of the piece as you work. When working on a one skein project, you either wind the skein into two balls and alternate with those, or if using a swift and ball winder, alternate between pulling from the center and outside of the ball.
This technique of alternating skeins interrupts the pooling and creates the more all-over, random pattern that these types of yarns are meant to create. While pooling is not always avoidable, even when you alternate skeins, more often than not, this process does the trick!