Indigo Jeans—the secret behind what makes blue jeans blue

Ever wonder what makes blue jeans blue?

Well, today is your lucky day! Stick with us, and you’ll learn everything you’ve ever wanted to know (and more) about indigo dye—the chemical responsible for giving your blue jeans their intense indigo color.

Many people are unaware, but indigo dye is almost as old as civilization itself. Archeologists have even found it in cloth wrapped around Egyptian mummies and on Babylonian tablets. It’s hard to believe, but the intense blue color comes from a couple of unassuming green plants:

The indigo plant

The woad plant

But getting the deep blue out of these plants is no easy task! And our ancestors devised quite the recipe to extract the dye—one that started with 3.5 gallons of stale urine and 4.5 ounces of salt.

That’s right, your eyes are not deceiving you—traditional indigo dye recipes called for vast quantities of urine. In some parts of the world, dyers even paid their neighbors for bowls of urine in order to create the dye that was called “blue gold,” for more reasons than one.

If you’re wondering how this traditional recipe was stumbled upon in the first place, we are right there with you. Unfortunately, we don’t have any clue, but we’ll let y’all marinate on that one for a bit…

Anyhow, the good news, for all of you out there who find yourselves a little bewildered, is that if your indigo jeans are younger than one hundred years old, their blue tint is a product of indigo and other less offensive ingredients. Modern day scientists have devised chemical alternatives that our blue jean suppliers have adopted.

New dye formulas for our indigo jeans—yet another reason to love science. Thank you science, indeed.

posted by: danielle on October 13, 2009 at 6:27 pm
filed under: Denim 101 | comments (1)
TAGS: history of jeans, blue jeans, indigo jeans

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On 10-13-2009, .(JavaScript must be enabled to view this email address) said

The urine and salt were used to alter the PH of the plants which helped the plant chemicals turn their signature blue. Napoleon adored the colour from the woad plant.
If you ever want to see real woad blue get in touch with me. I import a line of clothes and accessories dyed by the only full time woad merchant in the world.
  Cheers! Noelle Smith