Denim is a cotton textile that's probably most associated blue jeans. The most common color of denim is indigo, which is made using blue and white threads. Purchasing jeans online can be a little tricky because all denim is not the same. Denim is sold by weight, so a yard of five oz denim weighs five oz. Denim runs from five to 32 oz. The lower the number, the softer and more flexible the fabric, while the higher numbers are heavier and stiffer. In recent years, denim has been begun to be blended with other textiles like rayon and spandex to make a stretchy material that many feel is more comfortable to wear. When buying denim always read the swatch label. Each swatch is labeled with the fabric information, fiber contents, care instructions, and the width. Almost all online retailers offer fabric swatches.
Learning the Difference in Weight
When you're choosing the right denim for your project, you'll want to consider the needs of the garment. For example, a 20 oz denim is not going to bend and move for most garment uses. A five oz denim is not going to provide heavy enough denim for jeans or jackets, however, it will make beautiful shirts, skirts, and dresses that will drape well. Knowing that denim runs from five to 20 oz and that the less the weight, the lighter, softer, loft the denim will have, you can purchase or request samples of the weights you believe are in the scope you are looking for.
With this knowledge, you can assume an eight oz denim is just a tad more pliable and soft than the nine oz. The nine oz sample is just a tad more pliable and soft than the 10 oz sample. Durability-wise, they are pretty much identical. The real difference comes in at the drape and flexibility.
Traditionally, 12 to 14 oz is used for denim jeans. It will not ruffle or drape, which is something to consider if you're making a full skirt, say, for square dancing. If you want to make a strong, stand-on-its-own type of tote bag, then you want a 10 oz or higher denim. If you want to be able to fold the bag up and have it for when you need it, you can go down to a six oz denim. The choice is yours and what you want the bag to do.
The tote bag shown here is standing on its own (nothing is in the bag). It is made with Medium Weight Denim.
Before Using Different Weights
Always pre-wash your fabric and if you are mixing fabrics on one garment, make sure that they use the same laundering method.
Using a denim spandex blend is great for making comfortable everyday wear. However, this fabric wears out quickly. If your goal is a comfortable garment that will last, you might want to use a more durable fabric like jersey cotton.