Make the ginger flavor before adding bubbles
The syrup needs to cool before it meets ice and sparkling water. Warm syrup melts the ice and makes the drink taste diluted sooner. Set the strained syrup in a small heatproof container over an ice bath when you want to speed up that step.
Taste the lime before measuring the final drink
Limes differ in sharpness and in the amount of juice they give. Use the listed amount, then judge the balance after the sparkling water is added. More juice makes the drink sharper; more sparkling water makes every flavor quieter.
A little syrup goes a long way when the other ingredients are very cold. If you prefer a less sweet drink, hold a spoonful of syrup back rather than replacing it with more lime. You can always add it at the table.
Add sparkling water at the last moment
Pour gently down the inside of the glass and stir once or twice. A long, enthusiastic stir spends the bubbles before anyone gets to drink them. The lime round is optional, but its peel adds a pleasant smell near the rim.
This is a nonalcoholic cooler, not a fermented ginger beer. Use commercially carbonated water and keep the ginger syrup refrigerated. Do not leave it in a sealed bottle at room temperature to develop fizz.
