It's also available online. Amazon has it, as do other sources. The company name is Chilean Gourmet, and "Merken" is also known as "mapuche". Try any combination of those names on Google or Yahoo. Penzey's usually doesn't carry other companies' spice blends, since they make their own. (They may have something similar.) Otherwise, you can also try The Spice House, and there are many other spice companies online.

Merken is available at Whole Foods.