Make marinade. In a large zip top bag, combine all ingredients for the marinade. Mix well to dissolve the sugar.
1 cup beer or beef stock, 1 cup soy sauce, 1/2 cup Worcestershire sauce, 1/2 cup brown sugar, 4 cloves garlic, 2 Tablespoons black pepper, 2 teaspoons onion powder, 2 teaspoons red pepper flakes
Marinate jerky. Add the sliced eye of round to your marinade and toss gently in the bag to coat all sides of the meat with the marinade. Refrigerate 8 hours, or up to 24 hours. The longer it marinates, the saltier and stronger the flavor will be.
2 pounds eye of round roast
Remove from marinade. Remove the strips of marinated beef from the bag and place on paper towels. Pat dry.
Preheat. Set your smoker, oven (with the door cracked), or dehydrator to run at around 170 degrees F. Transfer the strips to the grill grate, jerky rack, or cooling rack and season the top with additional black pepper, if desired.
Smoke jerky. Smoke/cook for 2-3 hours (depending on the thickness of your slices, some thicker pieces can take 4-5 hours). Check often after the first hour to be sure your jerky is drying evenly. You are looking for jerky that is firm and still slightly pliable, but not soft. If you bend your jerky and it breaks, you've cooked it a little too long
Steam and store. Place the finished jerky in a gallon zip top bag while it is still warm. Don't seal closed all the way. The jerky will steam in the bag slightly and this step will make the jerky moist. If you added the curing salt, the jerky will last a couple of weeks on the counter. If you did not add in the curing salt, it will last a couple of weeks in the refrigerator.