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Forensic Yarn Identification

The "Mystery Stash" is a common challenge for fiber artists. Whether it's a lost label or a thrift store find, identifying your yarn's weight and yardage is essential for project success.

The Ratio Method

Calculating Yardage by Mass

(Total Mass ÷ Sample Mass) × Sample Length = Total Yardage

Real World Example

You found a mystery ball of blue wool. You cut a 10 yard piece and weigh it—it is 5 grams. You weigh the rest of the ball, and it is 95 grams.

(95g ÷ 5g) = 19
19 × 10 yards = 190 Total Yards
  1. 1
    Cut a Sample:

    Measure exactly 10 yards (or meters) of the mystery yarn.

  2. 2
    Weigh the Sample:

    Use a digital kitchen scale to find the weight in grams (Sample Mass).

  3. 3
    Weigh the Stash:

    Weigh the entire remaining ball or cake (Total Mass).

The Forensic Burn Test

Unsure if that yarn is wool or acrylic? Snip a small piece (1 inch), hold it with tweezers over a flame-proof bowl, and carefully light it. Observe the reaction to identify the fiber.

Fiber Type Flame Behavior Smell Ash / Residue
Wool / Silk Sputters, self-extinguishes Burning Hair Black, crushable ash
Cotton / Linen Burns quickly, yellow flame Burning Paper Fine, gray/white ash
Acrylic / Nylon Melts, drips, flares up Chemical / Plastic Hard, black bead

Common Questions

My yarn is a blend. What happens?

Blends are tricky. A wool/acrylic blend will often smell like hair but leave a small hard bead in the ash. If it's partially crushable but has hard bits, it's likely a blend.

Can I calculate yardage without cutting a sample?

Yes. Use our Yardage Estimator. It uses average Grist Coefficients for each weight class to give you a ±5% accurate estimate based on weight alone.