How to Make Glühwein
To make Glühwein, make a simple syrup and simmer it with some whole spices like cinnamon sticks, cloves, and star anise. Then turn down the heat and let barely simmer for at least 20 minutes and up to 3 hours.
If you want to make it ahead of time, let it cool to room temperature then store it in an airtight container in the fridge for up to 3 days. Rewarm in a pot over medium low heat.