"pH", Radishes, and Colour changes.

You will notice when you make this cocktail that the color of the liquid will completely change part way through, when you add the lime juice to the radish tequila. Fear not: your cocktail is still in good shape, if a bit flashier and diva-licious! What you will have witnessed is a flare of chemistry, or rather, a simple reaction to acidity by our new friend, the anthocyanidin (say that three times fast).

First,  a bit about pH: pH is a logarithmic scale used to measure acidity or alkalinity in water based solutions. It typically measures the activity of hydrogen cations in the solution, and the balance of hydrogen ions and hydroxide molecules. When that balance is even, you get a pH of 7, or the pH of pure water. A pH of 1 is extremely acidic: battery acid and gastric (stomach) acid are around these levels. 14 is extremely alkaline (or basic), with lye and, to a lesser extent, bleach, hanging around this level. We won't be cooking with any of these compounds, but pH does affect how some cooking interactions behave, such as coloration, scent, or even a Maillard reaction.

Red radishes are high in a chemical compound known as "anthocyanidin". The particular anthocyanidins in red radishes change color in the presence of shifting pH levels: Therefore, they can be used as a natural pH indicator. Red Radishes tend to be red or pink in acidic solutions (that's when the pH is less than 7), purple in neutral solutions (pH hovering around 7), and greenish-yellow in alkaline or basic solutions (pH is more than 7). That is why our cocktail will change color when you add the lime juice: Lime juice has a very acidic pH of 2 to 3, and when it hits the radish tequila, the color changes from a mild pink to a vibrant coral.

When we decided to infuse tequila with radish, we didn't know it would have this reaction! Kinnon actually remarked that she was a bit disappointed with the color after infusion. Then the lime juice hit, and the party started: we were thrilled with the color change, and the peppery notes from the radish worked so well with the spice of the tequila. The elderflower liqueur was crucial - it's sweetness brought out that of the tequila, and tied the entire drink together. This was a make-again for us: we were very pleased with this warm-weather, sunny colored cocktail, and we know you'll love it too.

How To Make It

First, we need to infuse tequila with radishes. This is as easy as placing cut radishes in tequila for 24 hours. It will get pretty funky, but all is well.

After 24 hours, strain the liquid into a jar and set it aside.

Add your tequila, elderflower liqueur, and lime juice into the cocktail shaker with some ice. Shake until well chilled, and strain into a chilled coupe glass.

Garnish with a spear of slight radish, and enjoy!

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