Ah, the power and the glory of yarn! When you step into a yarn shop, are you overcome with all the splendid colors, fibers, textures and yarn fumes? Does your head spin as you finger skeins, pet them, weigh them, drown in color, or dream of possible projects? You may fall so deeply in love with a yarn, you can't wait to cast on with it for your next sweater. But will this yarn do what you envision? Will you match the right yarn with the right project? Consider these five crucial tips.

1. Wrong Fiber?

2. The four basic types--protein, cellulose, cellulosic, synthetic--have different qualities. Protein means animal hair: sheep, alpaca, goats, rabbits, yak, buffalo and such. This gives us everything from angora to scratchy rug wool. Most wools are springy and have memory, good for nice stretchy ribbing. Alpaca? Not so much, but drapes well. Their scales trap air and absorb water for great comfort while wearing. Silk, in a class by itself, feels warm in winter, cool in summer. Cellulose comes from plants. This includes cotton, flax and hemp for everything from crochet thread to rope. Cotton feels cool in summer, but heavy, droopy, inelastic and some knitters find it hard on the hands while knitting. Cool, hard-wearing linen and hemp soften with repeated washings, have no stretch at all and feel scratchy to knit.

Bamboo shares many of cotton's qualities with a lighter weight. Cellulosic comes from plants and trees, broken down into a chemical slurry that's extruded into long strands like a spider makes his silk. This includes rayon and Tencel. New fibers like soy, corn and others appear on the market these days, great for wool-allergy folks. Synthetics are entirely man-made and include polyester, nylon and acrylics. This gives us everything from rope to fun fur. Synthetics can be machine-washed and dried, which is great for blankets, afghans, or toys. These include workhorse acrylics, showy fun furs and a million varieties of specialty textures. They can feel less comfy because they don't absorb moisture, but they won't rot or mildew. Blends of these four fiber types can share their great qualities and downplay drawbacks. Wrong Yarn Preparation?

3. Wool can be spun worsted for a shiny, sturdy yarn or spun woolen for a softer, cushier yarn. The fiber in yarns can be dyed before or after spinning, sometimes bleached or left the natural colors, hand-painted, kettle-dyed or a million other methods. Lighter colors show stitch definition better than dark colors. Solid and semi-solid colors work well for highly textured designs as they don't confuse the pattern. Multi-colored yarns can make the simplest knit look not-so-simple. For a garment worn near the face, choose colors that work well with your skin tone. The right color makes you glow--the wrong color, no matter how well-knitted, could make you look ill. Wrong Yarn Spin?

4. Multistrand means single plies are spun one direction, then singles are twisted together the same direction to form yarn. Did you ever notice the left leg of your knit stitches looks skinnier than the right in stockinette? That's a multistrand yarn. Cabled yarn has singles spun one direction, then singles are twisted together the other direction for a balanced yarn. Wrong Ply Combination?

5. Single ply can feel soft and plush, but pills. Two-ply can make great lace as it spreads stitches open. Three-ply makes round yarn that's great for socks and gives cables extra dimension. Yarns with even more plies have more strength, less pilling. Yarn spun into cobweb laceweight behaves well for airy shawls. Sock weight, DK and fingering weight yarn makes a splendid yarn for socks, hats, baby items, mitts, tights, scarves--you name it. Worsted weight works great for sweaters, hats, mittens, scarves, heavy socks, slippers, afghans, blankets, bags--either felted or not--and so much more. Bulky weights create heavy sweaters, coats, hats, scarves and slippers. Danger: Slippery When Wet?

Some fibers are weaker when wet. Some stretch or grow when wet. Dry clean only? Hand wash and lay flat to dry? Machine wash and dry? Each yarn comes with its own care instructions which may affect your choice of what pattern or garment you knit. How many sweaters and socks have become gigantic or miniature through the wrong laundry method? Don't discover this the hard way.

The right yarn at the right weight, knitted into a pattern that shows off the yarn's finer qualities can last for years of happy use. If you're still unsure how your particular yarn will work up, read The Knitters Book of Yarn: The Ultimate Guide to Choosing, Using and Enjoying Yarn by Clara Parkes. It's fabulous. Or if you check what others have made on Ravelry you'll see how their yarn behaved in various projects.