Combine brown sugar and cider. Use cheese cloth (or a coffee filter tied with plastic wrap / butcher's twine) to make a sachet of the mulling spices
Pour cider into a large stock pot.
Add sachet of spices and bring to a boil.
Let simmer for 30 minutes.
Remove sachet of spices and add lemon slides.
Notes
This is a recipe used by Sage Dining at Casady School in winter 2021. The quantities in this recipe have been scaled by a factor of 12. If you'd like to make 12 gallons instead of one gallon, refer to this scan of the original recipe.