To make things simple, buy it, brew it, try it. You will know if its good or not. Sadly, unless you want to buy the equipment, this is what you do. (Unless you're big time).
But once you brew and try different sources, you can look at the raws and tell about how potent it will be.
But once you brew and try different sources, you can look at the raws and tell about how potent it will be.