Step 1: In a medium saucepan, combine the blueberries, sugar, water, and lemon juice. Stir gently to mix.
Step 2: Bring the mixture to a gentle simmer over medium heat, stirring occasionally. Once simmering, reduce the heat to low and cook for 10-15 minutes, or until the blueberries have softened and burst. Gently mash some of the berries with a spoon or potato masher to release more juice.
Step 3: If you prefer a smooth syrup, place a fine-mesh sieve over a heatproof bowl. Carefully pour the blueberry mixture through the sieve, pressing down on the solids with a spoon to extract all the liquid. Discard the solids (or save for another use, like stirring into yogurt).
Step 4: Return the strained liquid (or the unstrained, chunky mixture if preferred) to the saucepan. Bring it back to a gentle simmer over medium-low heat. Cook for another 5-10 minutes, stirring occasionally, until the syrup thickens to your desired consistency. Remember, it will thicken further as it cools.
Step 5: Remove the blueberry syrup recipe from the heat and let it cool completely to room temperature. Once cooled, transfer the syrup to clean, airtight jars or bottles. Store in the refrigerator for up to 2-3 weeks. For longer storage, the syrup can be frozen for up to 3 months.