Add the ginger and water to a saucepan and bring to a gentle simmer. Simmer uncovered for about 30 minutes, or until the liquid has reduced by roughly half.

Remove from the heat and let the ginger steep as the mixture cools. Strain through a fine-mesh strainer.

Stir in the vanilla extract, lemon juice, and honey. Adjust the honey to taste.

Transfer to an airtight jar and refrigerate for up to 1 week.

To make ginger ale, fill a glass with ice and combine 1 part ginger concentrate with 3 parts sparkling water. Adjust to taste.