A great spice rub is a cook's best friend and can lend a blast of flavor to almost any dish. I think of it more as a special seasoning mix, rather than something meant only for the grill, and use it on or in everything from sandwiches to salad dressing.

When you have a combination of vibrant flavors that makes your palate happy, there's not much it won't improve. On the flip side, a lackluster spice rub can turn a dish with potential into something more "meh."

Sadly, not all spice mixes are created equal, especially those that are premade. That's why I like to make my own, using premium spices.

Quality and freshness are important elements when determining whether a spice will be able to pack a flavorful punch. And while there's no AAA rating when it comes to spices, a few tips will help ensure that you are buying the best.

Look at the label. When shopping for spices, look to see if the label states where the spice comes from and gives a "best-used-by" date. Premium spice brands will often give that information and it's a good indicator of quality.

Buy whole whenever possible. The clock starts ticking on the potency of a spice the minute it's been ground, so I buy my spices whole as much as possible and grind them myself, just before using.

Shop at a busy store. If you can't find a best-used-by date, make sure you are shopping at a place that seems to turn over its product fairly quickly. If you have to brush a layer of dust off the jar just to read the label, you can likely assume the spice isn't fresh.

Date it. Once you get the spice home, make sure to write the date you bought it on the label and toss any older than a year.

Toast whole spices. Before you grind whole spices, toast them in a dry skillet until they are fragrant. It doesn't take long, but you'll be surprised at the difference it makes in the aroma the minute you open up the grinder. That fragrance, which comes from volatile oils, translates into flavor.

And flavor is king in a spice rub. That's why mixing your own, as we've done for this week's Grilled Spice-Rubbed Chicken Thighs with Lemon and Herbs, is always a good idea.

The recipe makes more spice rub than you'll need, but that's not a problem. You can also use it to season your next steak or pork chops, roasted vegetables, mac and cheese, scrambled eggs — well, you get the idea.

Grilled Spice-Rubbed Chicken Thighs with Lemon and Herbs

Serves 4 to 6.

A fragrant dry rub infuses the chicken with warm spices and a touch of heat. Grilling the lemon halves gives them a slight sweetness and helps release their juices. This recipe makes more spice rub than you'll need for the chicken; store the remainder in an airtight container. From Meredith Deeds.

For the spice rub:

• 3 tbsp. kosher salt

• 2 tbsp. brown sugar

• 2 tbsp. smoked Spanish paprika

• 1 tbsp. coarsely ground black pepper

• 2 tsp. ground cumin

• 2 tsp. ground coriander

• 1/2 tsp. cinnamon

• 1/2 tsp. cayenne

For the chicken:

• 2 lb. boneless, skinless chicken thighs

• 2 tbsp. olive oil

• 3 lemons, halved

• 1/4 c. Italian parsley, mint or cilantro leaves (or a combination), torn to pieces

Directions

Prepare a grill for medium heat.

In a small bowl, combine salt, sugar, paprika, black pepper, cumin, coriander, cinnamon and cayenne.

Brush the chicken all over with the oil. Season the chicken thighs on both sides with 4 tablespoons of the seasoning, reserving the rest for another use.

Grill chicken, turning once, until you see some good grill marks and chicken is cooked through, 8 to 10 minutes. Transfer to a platter.

Grill lemons, cut side down, until lightly charred and juices start to caramelize, about 4 minutes.

Sprinkle herb leaves over the chicken and serve with the grilled lemons on the side.

Meredith Deeds is a cookbook author and food writer from Edina. Reach her at meredithdeeds@gmail.com. Follow her on Instagram ­at @meredithdeeds.