Berries give this sweet-tart lemonade its pink color and cold seltzer water adds maximum bubbles.
Pink Lemonade Syrup
Sparkling Pink Lemonade
For the pink lemonade syrup: Cut 1 lemon in half lengthwise through both ends. Lay lemon halves, flat side down, on cutting board, then cut each half crosswise into thin semicircles. Discard ends.
In medium bowl, combine lemon slices, berries, and sugar. Use potato masher to mash until berries are broken down and sugar is completely wet, about 1 minute; set aside.
Cut remaining 4 lemons in half crosswise (the short way). Use citrus juicer to squeeze juice into liquid measuring cup. You should have about ¾ cup juice. (Save any extra juice for another use.)
Pour lemon juice into bowl with lemon-berry mixture. Use rubber spatula to stir until sugar is completely dissolved, about 1 minute.
Set fine-mesh strainer over second medium bowl. Carefully pour mixture through strainer. Use rubber spatula to press on lemons and berries to get out as much juice as possible. Discard lemon slices and berries in strainer.
Pour strained pink lemonade syrup into jar with tight‑fitting lid. (Pink lemonade syrup can be refrigerated for up to 1 week.)
To make 1 Sparkling Pink Lemonade: Stir or shake pink lemonade syrup to recombine. Place ice in glass. Pour cold seltzer into glass over ice. Add 3 tablespoons pink lemonade syrup to seltzer. Use spoon to stir gently to combine. Serve.