Spices can be used in brewing specialty beers, and are especially common in holiday brews. Some common spices used in brewing (and this list is by no means exhaustive!) are cinnamon, cloves, ginger, allspice, coriander, orange peel, anise, cardamom, nutmeg, and more. Spices can add a special character to lightly hopped recipes.
Brewing with spices
Spice character is all about flavor and aroma. They will not contribute significantly to the body or color of your beer. Off-flavors are not uncommon with spices unless they are used sparingly and carefully. Freshness of the spice is critical to the final character, as the extractable taste qualities diminish over time in storage. You will achieve better results by grinding or cracking your own whole spices than by using pre-powdered supplies.
Adding to boil
Spices can be boiled with your wort. This is the easiest way to extract unwanted off-flavors from your spices, so most spices are boiled for a short period at the end of the boil, or added right at the conclusion of the boil.
Adding to secondary fermentation
You can add spices to a secondary fermentation and extract their essence in the same manner as dry hopping. Allow at least a week for the spice character to enter the beer.
Adding at bottling time
Spices can be added at bottling, either as whole/ground, or as an infusion. To create an infusion, add your selected spices to a bottle of vodka and let it steep for a month or more. Then use the spice-flavored vodka to add controlled amounts of flavor to your beer at bottling time, tasting as you go. This method requires preparation in advance, but gives you great control over the final taste, since the behavior of raw spices can be unpredictable.