Are Some Yarns "More Equal" Than Others?

All animals are equal, but some animals are more equal than others.

— Napoleon Pig, George Orwell's Animal Farm

A couple of days ago, I mentioned that I was using Red Heart Soft Essentials (a yarn I can get at Michaels) to work a pattern designed for Bernat Beyond yarn (which our local Michaels does not sell).

There are a number of theories and rules of thumb for substituting one yarn for another: 

• If the finished item is to remain the same size, the yarns should be of similar thickness
• Alternatively, you can to change the number of stitches in your pattern (ideally for an even number of pattern repeats) to come up to the same measurements. 
• Different fibers will handle differently in wearing and cleaning — cotton knits will become shorter and wider, wool will full or felt, acrylics will pull and pill. Try to keep yarns that will handle similarly after the project is finished.
• Substitutions in both yarn and gauge can be used to scale patterns up and down — use a similar color and texture of fingering yarn to make an American Girl doll's sweater look more identical to that of her owner's worsted sweater, with similar numbers of stitches and rows for each garment piece.
• Most craft yarn manufacturers' yarns of a given weight, fiber blend, and texture can be used interchangeably.

In theory, you should be able to swap out Red Heart SuperSaver for Loops & Threads Impeccable, Lion Brand Vanna's Choice or Heartland, etc. In the cotton utility area, Lion Brand Cotton-Ease should be one-for-one interchangeable with its 24/7 Cotton Yarn replacement or with Lion's Kitchen Cotton, or Lily Sugar 'n Cream, Bernat Handicrafter, Red Heart Creme de la Creme, etc.

Based on those general rules of interchangeability, I used some leftover Sugar 'n Cream to make Lion's Orient Point Washcloth, originally designed to use Cotton-Ease, using size 7 aluminum needles (the recommended size) and the recommended number of stitches. The sample on the pattern uses seven repeats of the eight-row eyelet pattern to create the 10" square; I only needed five and a half repeats.

At first glance, this made me think that Sugar 'n Cream might be a thicker yarn than Cotton-Ease. Then I looked at the two yarns on Ravelry.

According to Ravelry, Cotton-Ease is a 50/50 cotton-acrylic blend with a thickness of 8 wpi (wraps per inch), and a gauge of 17 stitches per 4" on size 8 needles. Sugar 'n Cream is a 100% cotton yarn with a thickness of 9 wpi (i.e., slightly thinner), and a gauge of 20 stitches and 27 rows per 4" on size 7 needles. (Note: yarn-wrapper gauges are always based on stockinette stitch; the gauge for a particular pattern may vary.) 

In other words, Sugar 'n Cream should be slightly thinner than Cotton-Ease. (Worse for my theory, my own test came up with 11 wpi for the Lily yarn.)

I finally checked the gauge (in eyelet pattern) on my finished article: 16 stitches and 24 rows per 4" in eyelet pattern. I guess I knit more loosely than I thought I did.

Which goes to remind us, always check your gauge before starting a project where fit is an issue.