A bright, zippy, and tangy refreshment for today's festivities.
I'm a sucker for kids' lemonade stands by the side of the road, which I'm physically incapable of passing up. As a result, I spend most of my summer politely choking down some of the worst lemonade on the planet in support of my littlest neighbors .
If you haven't already read up on my syrup method, what makes it so perfect for lime- or lemonade is that it doesn't require any heat or dilution. Instead, it allows the residual moisture and citric acid in the rinds to dissolve sugar over time. The result is a potent, semi-inverted fresh citrus syrup that's both flavorful and sweet, tempered by the subtle bitterness of essential oils drawn out from the rind.
Avid bakers may want to zest the limes for another project before getting started, but it's fine to leave the zest intact; there's no major impact on the syrup's flavor either way. Whatever you choose, maximize their yield by letting the limes come to room temperature and rolling each one against the counter to soften its rind.
The rinds and sugar are then left to macerate until syrupy and thick. That can take as little as a few hours, but, if you're not in a hurry, you can let them stand for up to 12 hours—a make-ahead option I've relied on any number of times, whether because I have to go to work or just while I get some sleep. Any longer than that and the syrup will begin to develop an unpleasantly bitter edge.