Add the sugar, water, and allspice berries to a saucepan and stir to combine.

Heat over medium-high heat until the mixture comes to a boil.

Let it boil gently for about 2 minutes, stirring occasionally.

Remove from heat and allow the syrup to cool for 10-20 minutes, tasting as it steeps for the desired strength of syrup.

Strain the syrup through a fine mesh strainer, then strain again through cheesecloth to remove all allspice berries and any remaining particles.

Pour into a clean jar or bottle. Store in the fridge for up to 2 weeks or freeze for up to 3 months.