If your bulgur is still too hard after 30 minutes (a pleasant bite is normal), then the simmering temperature was probably too high. This causes the water to quickly evaporate without being absorbed into bulgur, resulting in par-cooked grains. Add more boiled water (about 1/2 to 1 cup) and simmer until no more steam is coming out. Note that the texture won't be exactly the same as properly cooked bulgur pilaf.