Corn tortillas made in the comfort of your own home can taste so much better than store-bought tortillas that the effort of preparing them is worth it. Most people; however, don't have the time or equipment to actually grind dried corn. That's why many supermarkets — especially in areas with large Hispanic populations — stock tortilla mixes. You can choose the best of these by looking for a specific label, a short list of traditional ingredients, lack of chemical preservatives and clean market conditions.
The first thing to look for when shopping for quality tortilla mix is a specific product label. For those not familiar with Hispanic cooking, it can be easy to confuse tortilla mix with other corn-based products, such as polenta or cornmeal. Those products do not have the right ingredients to make good tortillas. Mixes intended for use in making homemade tortillas will be labeled “tortilla mix.” In areas with a high Hispanic population, mixes may also be labeled “Masa Harina.”
High-quality tortilla mix will also have a short, specific ingredient list. The first ingredient you should look for is stone-ground cornmeal, which is traditional but also happens to offer nutritious whole grain and fiber. Calcium hydroxide – also called “cal” or “slaked lime” – is a classic alkaline additive that helps the body digest the vitamins in corn, such as niacin. Most tortilla mixes also include salt, because tortillas made without it tend to taste bland or flat.
Just as there are ingredients to look for in tortilla mix, there are also some you should avoid. Food-borne pathogens do not survive well in dry, salty environments such as those that exist in grain-based, salted mixes. There is, therefore, no need for chemical preservatives. If you see chemical preservatives on the product's ingredient list, put it back. Those chemical additives will detract from your tortilla's flavor, possibly giving the finished product a sharp, sulfuric or otherwise unpleasant flavor.
Finally, the best tortilla mix should be sold under sanitary conditions. Most mixes are sold boxed, though larger supermarkets and health food stores also often stock tortilla mix in bulk. If you're buying a boxed mix, the box itself and all seals should be intact, with no holes or dents. Bulk mixes should be stored in clean, lidded containers. When you see visible dirt or grime on the bins, or the floor near them, you should buy from another store.