Combine the blueberries, sugar, water, and lemon juice in a small saucepan.

Place the saucepan over medium heat. Once the first bubbles appear and the mixture starts simmering, lower the heat and let the mixture simmer for 10 minutes, stirring occasionally.

After simmering, remove the heat and let it cool to room temperature.

Balance a fine mesh strainer, muslin cloth, or coffee filter over a bowl and tip in the blueberry mixture. Let it drain completely.

Pour it into a clean glass jar or airtight container.

The syrup can be stored in the refrigerator in a sealed container for up to 2 weeks or frozen for up to 3 months.