To make the cordial, combine all the cordial ingredients in a medium saucepan over medium heat. Bring the mixture just to a simmer (don’t boil), stirring to dissolve the sugar. As soon as it comes to a simmer, take the pan off the heat, cover and let cool completely. Strain into a clean container, and store covered in the fridge for up to 1 week.

To make the fizz, add cordial and tequila to a 12 ounce glass with ice, stirring to combine and chill. Top off with chilled IPA (you’ll use around 4 ounces or 1/3 bottle). Garnish with grapefruit peel.