Mulled Apple Cider

'Tis the season for mulled apple cider... here's a great recipe for it:

2 qt. bottle of apple cider (not the unfiltered stuff for this, please)
1/2 c. packed brown sugar
8 allspice berries
4 cinnamon sticks, broken in half
12 whole cloves
1 large orange
1 8-in square of double-thick cheesecloth, rinsed in water and squeezed out

Combine apple cider and brown sugar in slow cooker. Wrap allspice berries and cinnamon stick halves in cheesecloth; tie securely with cotton string. Stick cloves randomly into the orange and cut the orange into quarters. Place spice bag and orange quarters into the juice mixture. Cover and cook on high 2.5 to 3 hours. Once cooked, cider may be turned to low and kept warm up to three additional hours. Discard spice bag and orange quarters. Ladle cider into mugs and garnish with additional cinnamon sticks, if desired.