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 (it's their childlike entrepreneurship that I find so refreshing).
When it comes to making a frosty pitcher of my own, I crave lots of intense fresh fruit flavor, and I also want a change of pace, which usually means limes instead of lemons. And, given my obsession with turning leftover lemon rinds into a citrusy fresh syrup, it was only a matter of time before warm weather drove me to apply the technique to limes.
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. It's an uber-tart and aromatic syrup that adds considerable complexity to the flavor of the plain lime juice typically used for limeade.
In order to provide six generous servings, my recipe starts out with three pounds of Persian limes—a number that can be scaled up or down to suit your needs. It works just as well with an equal quantity of lemons, but I've found that oranges make for a cloying drink (although the syrup itself is lovely).
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.
Halve and juice the limes, using any method you prefer, then set the juice aside until later (no need to strain). Cut the rinds into chunks to expose more surface area, then combine them with about half their weight in sugar.
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. (That bitterness can sometimes be used to good effect in other applications, say, by citrus enthusiasts looking to mimic the bitter intensity of Key limes.)
Finishing the limeade is a simple matter of adding water and some of the reserved fresh juice, then straining it through a fine-mesh strainer to "rinse" the rinds.
At this point, the limeade is rather sweet and concentrated—but for good reason! The high proportion of sugar has a somewhat preservative effect, allowing the mixture to be refrigerated for up to a week without any substantial loss of flavor. That's handy when prepping for weekend cookouts or holiday gatherings, while also making the finished drink more customizable for those who want it more or less tart; just add more water and/or fresh lime juice to taste. Remember that, when it's served in a pitcher of ice on a hot day, dilution will happen before the first glass is poured, so be careful with how much water (or booze) you add.
On that note, my undying love for gimlets has me pairing limeade with gin, but, after gifting a bottle of the concentrate to a friend, I've learned that tequila works nicely as well. You can even replace the water with a dry white wine for a citrusy sangria. Not that there's any need to spike it! This bright, zippy limeade is perfectly tangy and refreshing all on its own.