The best way I have found to add spices to anything, whether it's cider or beer or whatever, is to make a tincture with vodka. Guess how much spice you want to add, place this in a glass and pour a few ounces of vodka over it. Stir well, then let this vodka tincture sit for a day or two. Finally when you are ready to spice up your brew, add just a very small amount of your flavored vodka at a time, like 1/2 teaspoon at a time, blend it with the brew, taste it, and see if that's enough or if you need to add a little more. Leave the spice solids behind and only add the clear portion of the vodka. I find that I usually don't even use it all, maybe only one third to one half as much as I thought I would need goes into the brew. It is much better to add a little at a time until it tastes right than to add too much, because once you have done that, obviously you cannot remove it any longer.