This spice starts as reddish-purple berries from sumac plants. The small berries, which grow in big clusters, are dried and ground into a bright red spice. In fact, the word "sumac" traces its etymology way back to the word for "red" in Syriac, a language that was first prominent in the second century BCE. Since sumac can't be found in run-of-the-mill grocery stores, and of course it's best to get the freshest, highest quality spices to ensure optimal flavor, I headed to Penzey's at Tempe Marketplace to pick up a jar. At $3.75 for a small jar (1.2 oz.), you'll get enough to experiment with quite a few dishes. Once you get a taste, you'll be putting it on everything, maybe even mixing up an original blend of za'atar to keep handy on the kitchen table.