THC is alcohol soluble. Your best extraction method is done high proof alcohol. I've ground and dissolved "hemp" in a small amount of grain alcohol before and it makes for an awesome mix drink.
However, using enough hemp for a 5 gal batch would be crazy expensive.
With all that said, I think your best bet would be to grind and soak the hemp in grain alcohol for a few days, strain, and add that mixture to a batch at bottling/kegging.