How to Blanch Herbs for Syrups + a Mojito

All week long, Jeffrey Morgenthaler of Portland's Clyde Common and Pepe Le Moko will be sharing recipes and techniques from his new book, The Bar Book: Elements of Cocktail Technique. Follow along to win one of five copies we’re giving away -- and to perfect your at-home cocktails.

Today: A trick for herb-infused syrups that won't turn brown, and a mojito recipe that you can make for a group, without spending the whole night muddling. 

I desperately wanted to put a Mojito on the cocktail menu at my first restaurant job back in 2001. It was a big, busy place and after a couple of hectic weekends, I realized we needed a faster way to prepare this labor-intensive drink. And thus the mint simple syrup was born. The only problem was that steeping fresh mint leaves in hot simple syrup, as we did, resulted in a syrup that turned brown after only a few hours and left us with a rather unappetizing-looking cocktail.

More: Learn how to make symple syrup without any heat. 

Hilariously, our solution back in those days was to add Midori for a little green coloring and name the drink an “Asian Mojito.” Had I known better, we could have saved more than a few palates from that sickly sweet concoction we were serving. 

Herb syrups prepared in this fashion turn dark because of a process called enzymatic browning: Substances in plants called polyphenols allow enzymes to cause browning when they come in contact with oxygen. Your herb syrup may look clear or a lovely shade of light green when you first make it, but once you’ve exposed it to oxygen, it can darken to an unappealing shade.

The way to stop those enzymes from doing their thing is by subjecting them to a little heat. For that, we use a cooking technique called blanching. Blanching simply entails boiling something for a few seconds (or up to a few minutes for vegetables) to deactivate the enzymes, and then stopping the cooking process by plunging the ingredients into ice water to maintain their fresh flavor.

To blanch your herbs, bring a large pot of water to a boil. While you wait, put some cold water and ice into a medium bowl, and arrange a double layer of paper towels on the counter. 

Once the water is boiling, gather your herbs. Don’t pick the leaves; simply leave them on the stalk for now. Holding them by the ends, plunge the stalks into the boiling water. I blanch softer, more delicate herbs (such as mint, tarragon, and basil) for 15 seconds, and hardier herbs (like thyme and rosemary) for 30 seconds. 

More: Read up on everythink you need to know about mint, basil, and thyme.

Once the time is up, remove the herbs from the boiling water and plunge them immediately into the ice bath. Let them stay there for a full minute, remove them from the water, and pat them dry with the paper towels. 

The next step is easy: Remove the leaves, throw them in a blender with premade simple syrup, and blend on high speed for about 1 minute. All that’s left to do is strain out the solids using a fine-mesh sieve, and bottle the syrup.

This little trick is a great way to make mojitos for a big group (say, while hosting a summertime Cuban cookout) and avoid spending the entire evening in the kitchen making drinks. Simply omit the muddled mint from a traditional mojito and substitute this mint syrup for the plain simple syrup. 

Mojito

Makes 1 drink, easily scaled up

For the mint syrup:

12 ounces water
12 ounces sugar
5 large sprigs (or 7 medium sprigs) fresh mint

For the mojito:

1 1/2 ounces mint syrup
2 ounces (60 milliliters) white rum
1 ounce (30 milliliters) fresh lime juice, plus the spent lime half
Crushed ice
2 ounces (60 milliliters) chilled soda water
Ice cubes
1 bunch fresh spearmint, for garnish

See the full recipe (and save it and print it) here.

We're giving away a copy of The Bar Book every day this week! To enter to win today's copy, tell us in the comments: What's your favorite summer drink? We'll pick five winners at random next Monday, July 21!

Photos by Alanna Hale. Excerpted from the book The Bar Book: Elements of Cocktail Technique by Jeffrey Morgenthaler. Reprinted with permission from Chronicle Books. All rights reserved.