The best place to store grains to reduce the risk of cross-contamination is

Keep it Clean and Separate at Home

Begun says that the easiest way to prevent cross-contamination at home is to make it 100-percent gluten-free. But that's not always practical, especially for a shared kitchen. The key is to keep things clean and separated. That means crumb-free food preparation surfaces, separate or carefully cleaned cooking and serving equipment for gluten-free foods, strategic food storage and good dishwashing skills.

Begun offers some at-home tips:

Place gluten-free items above gluten-containing items in the pantry and refrigerator, so gluten particles don't fall or settle into gluten-free foods. Identify gluten-free foods with an indelible pen or stickers. Thoroughly clean all dishes, pots, pans and utensils between uses. Purchase a second, gluten-free toaster. Use a separate set of cutting boards for gluten-free food prep. Have two sets of condiment jars or a squeezable condiment container, reducing the risk of contaminated spoons getting dipped into your mustard or peanut butter.