Combine the blood orange concentrate and water in a small saucepan (2 to 1 ratio). Add 1/2 cup sugar, a small pinch of salt and bring to 180 degrees on the stove (no higher). Chill completely before using.
To make the blood orange mezcal gimlet
Combine blood orange cordial, lime juice, mezcal and Angostura bitters with ice in a cocktail shaker. Shake until chilled and strain into a chilled coupe glass and garnish with a blood orange wheel.
Recipe makes 1/2 cup blood orange cordial.
The blood orange cordial can be stored covered in the refrigerator for up to a week or in the freezer for 6 months.