To preserve the freshness of the chile powder you are buying, I grind the powder when I fill your order. I do not add silicone dioxide, also known as anti-caking agent, to my powders, this is 100% pure chile powder. If the powder clumps in humidity, simply break the clumps up.
To keep your cost down all powders are shipped in ziplock bags. Use the powder straight from the bag or transfer to your spice jar.