100% Cotton Thread
is the traditional choice for sewing and quilting. A 50wt cotton thread is still the most popular choice for quilt piecing. Cotton is a natural thread that gives a soft, matte look.
Cotton thread is available in a wide range of weights, and is suitable for most sewing and embroidery projects. 40wt and 50wt are the most common, but cotton threads range from 8wt to 100wt.
Cotton thread does not stretch a great deal, and will break if pulled too tightly. Cotton thread will fade with the sun, and shrink in the wash, so treat it as you would cotton fabrics.
Most cotton threads sold now are mercerized. This is a chemical and heat process that increases the luster of the thread. During the mercerizing process, fuzzy threads are burned off, creating a smoother surface. This smooth surface reflects light, increasing the luster of the thread. It also has the effect of increasing water absorbancy, making the thread easier to dye.
Long staple cotton is finer and stronger than regular cotton. Most high quality threads are made with long staple cotton, creating a softer, stronger, higher luster thread. Long staple threads tend to have fewer slubs, lumps of lint spun into the cotton threads.