What type of soda is used in a London Pickup?

In a London Pickup, soda water is the correct choice because it serves as a neutral mixer that enhances the drink's overall flavor without overpowering it. Soda water adds a slight effervescence and dryness that helps maintain the balance of flavors in cocktails, making it particularly suitable for drinks that rely on the taste of the primary alcohol and other ingredients.

While Sprite and 7-Up are lemon-lime sodas that contain added sweetness and flavoring, they would alter the intended profile of the London Pickup. Club soda, while also carbonated like soda water, typically has added minerals that can create a slightly different taste experience; however, soda water is often the preferred choice in classic cocktail recipes to highlight the original ingredients.