cracked versus ground coriander

Is there a reason why most recipes say to use cracked coriander, as opposed to just grinding it in a spice grinder?

Thanks.

three reasons. using ground coriander will make it very difficult to remove before you bottle it. second, by grinding the coriander seed you expose a lot more surface area, this can cause too much flavor to be imparted to the beer. third, by cracking the seeds yourself you get the maximum amount of essential oils from the seed. if you buy ground coriander from a sotre, you can lose a lot of flavor by the time you get to use it.