Bring the water and sugar to a boil in a small saucepan. Reduce the heat and simmer until the sugar is completely dissolved, 5 minutes.
Remove from the heat and add the orange zest, cinnamon sticks, cloves, and allspice. Cool for 1 hour to allow the flavors to infuse, then strain into a clean glass jar, and stir in the vodka (optional). Cover with a tight-fitting lid and refrigerate for up to 2 weeks (longer with vodka added - see notes).
Cranberry Simple Syrup
Bring the water, sugar, and cranberries to a boil in a small saucepan. Reduce the heat and simmer until the cranberries burst, 7 to 10 minutes.
Remove from the heat and stir in the cinnamon sticks, star anise, cardamom pods, cloves, and orange peel. Cool for 1 hour to allow the flavors to infuse, then press through a strainer. Pour syrup into a clean glass jar and stir in the vodka (optional). Cover tightly and refrigerate for up to 1 week (longer with vodka added - see notes).
Rosemary Simple Syrup
Bring the water and sugar to a boil in a small saucepan. Reduce the heat and simmer until the sugar is completely dissolved, 5 minutes.
Remove from the heat, add the fresh rosemary, and set aside to cool for 30 minutes. Strain the syrup into a clean glass jar and stir in the vodka (optional). Cover tightly, and refrigerate for up to 1 week (longer with vodka added - see notes).
Spiced Ginger Simple Syrup
Bring the water, sugar, and ginger slices to a boil in a small saucepan. Reduce the heat and simmer gently for 20 minutes.
Remove from the heat, use a slotted spoon to remove the ginger, then add the cinnamon sticks, cardamom pods, cloves, and allspice berries. Set aside to cool for 1 hour, then strain into a clean glass jar and stir in the vodka (optional). Cover tightly and refrigerate for up to 2 weeks (longer with vodka added - see notes).
Notes
Using vodka to preserve flavored simple syrups:
Although plain simple syrup will keep for up to one month when refrigerated in a tightly sealed container, adding ingredients like fruits, spices, and herbs will shorten the shelf life considerably.Adding a tablespoon of vodka (preferably 100-proof) to a cup of prepared simple syrup will extend the refrigerated shelf life to about twice the amount of time listed in the recipe instructions above.Whether you opt to add the vodka or not, keep an eye out for a cloudy appearance, change in color or an off odor. These are all signs that your simple syrup may be past its prime.Given how inexpensive and easy it is to make, we always err on the side of caution and whip up a fresh batch if we’re just not sure.