Rhubarb doesn’t get anywhere near enough love, especially in the U.S., but it’s a seasonal treat that we look forward to every spring. Most people are likely familiar with it as a regular partner to strawberries in pies, crumbles and in our strawberry-rhubarb cheesecake (go make it!), but it can do so much more. Its tart, almost green apple flavor lends itself to applications both sweet and savory. We’ve used it in chutneys, compotes, curds and crumbles … but our favorite way to use rhubarb is in cocktails. And hence, the rhubarb gin sour.
a few interesting facts about rhubarb
We’ve been growing rhubarb for a few years now, and it’s finally mature enough that we can harvest enough to do some fun things with. The first variety we planted never developed that gorgeous ruby color, and we realized that the color of rhubarb really doesn’t tell you how ripe it is. The hue is determined solely by variety; different cultivars produce different colors. Rhubarb varieties are classified as either red or green. Green types are again differentiated as green and speckled (with a little pink). Red stalk varieties often go by the term Crimson (you’ll see varieties called Crimson Cherry, Crimson Red, or Crimson Wine; the cultivar we used is actually called Canada Red).
Green and red varieties taste very similar, tart with just a hint of vegetal earthiness. In all varieties, the leaves are poisonous and should not be eaten.
some even weirder facts about rhubarb
Rhubarb is one of the only vegetables that you can actually hear grow. There is a 9-square-mile area in West Yorkshire, England referred to as the “Rhubarb Triangle,” between the towns of Wakefield, Morley, and Rothwell. After two years growth in the field, rhubarb plants are transferred into pitch-black “forcing sheds”. The plants, being gullible and trusting, think they’re now underground, so they spend all their stored-up root energy into growing taller at an accelerated rate, in order to reach the sunlight that they’ll never find. And if you’re quiet in the sheds, you can hear the rhubarb cells crackle. Heartbreaking!
Another fact; have you ever heard the term “walla”? In film and television, walla is a sound effect imitating the murmur of a crowd in the background. In old timey radio days, actors would repeat the phrase “walla walla walla” to mimic the indistinct chatter of a crowd. But in the UK, actors say “rhubarb, rhubarb”.
There is, of course, a city in Washington state called “Walla Walla”. There is, as yet, no town in the UK called “Rhubarb”.
how to make rhubarb syrup
Sweet, tart and gloriously pink, making rhubarb syrup could not be easier. If you want your syrup to have this gorgeous color, use the brightest red stalks you can find. Rhubarb tends to get woody and tough as it ages, but because we’re just extracting the flavor and color, this is a great way to use up rhubarb that’s past its prime.
Chop the rhubarb stalks into roughly 1-inch pieces and add them to a pot with 1 1/2 cups of water. Bring it to a boil and lower the heat to a simmer. Cook until the rhubarb is fully soft and almost falling apart, about 15 minutes. Place a fine mesh strainer over a bowl and if you want a clear syrup, line the strainer with a couple of layers of cheesecloth.
Carefully pour the rhubarb through the strainer. Gently press on the rhubarb with a spoon to expel as much liquid as possible, or just let it sit for an hour or so. The rhubarb pulp will be unsweetened, so you can either discard it or mix it with sugar or another sweetener and use it as you would any other stewed fruit (it’s delicious on yogurt or vanilla ice cream).
Return the liquid to the saucepan, add the sugar and turn the heat to medium. Bring it to a simmer and cook just until the sugar dissolves, about 2 minutes. Remove from the heat, stir in the lemon juice, and let the syrup cool to room temperature. If you want a very clear syrup, strain once again, then transfer it into a clean glass jar or bottle. The rhubarb syrup will keep well in the refrigerator for up to a month.
what type of gin to use?
In the simplest terms, gin is basically a neutral spirit, flavored either by compounding or distillation, with juniper and various other seeds, roots, fruits and herbs. These are known as botanicals. There are many, many styles and variations, but for our Rhubarb Gin Sour, we recommend using London Dry. London Dry gins are juniper forward, and tend to include coriander, angelica root, citrus peels, and sometimes orris root.
Really any good botanical gin would be great, though we don’t recommend using flavored gins (like sloe or citrus) which might mask the flavor of the rhubarb. In our testing, we used Plymouth Gin, which is very similar to a London Dry.
egg white foam in cocktails
The addition of egg white adds viscosity and a light creaminess to cocktails. It’s especially effective in cocktails that are particularly tart and lemony, like the classic Pisco Sour, or of course this rhubarb gin sour. It transforms what would otherwise be a bracingly lip-puckering drink, into something balanced and decadent.
The fresher the egg, the more stable the foam will be. This is to do with the strength of the proteins in the albumin. Acid also helps to stabilize an egg foam, so shaking the egg white with the lemon juice and other acidic cocktail ingredients is helpful.
If you don’t want to use egg white, you can substitute aquafaba.
What Is Aquafaba?
Aquafaba is the liquid found in a can of chickpeas (don’t use the liquid from any other beans, they won’t work as well). This starchy, vegan liquid is a great binder and it whips to creates a foam similar to egg white.
dry shake vs. reverse dry shake
“Dry shaking”, which basically means shaking the ingredients together first, before adding ice, allows the mixture to combine without dilution (hence the phrase ‘dry shake’). Then, after the ingredients have been combined and become bubbly, ice is added to chill and dilute the drink.
There are some who claim that the opposite technique works even better – the ‘reverse dry shake’. This is the inverse of a dry shake, where you shake the cocktail’s ingredients with ice first. It is then strained and shaken again, this time without ice, before serving.
Both methods work, but we find the reverse dry shake to be a bit of a pain and more work, for a similar result.
Another fool-proof way of creating foam is by using a blender or stick blender. This method makes a longer lasting foam, and is also helpful for making batches of drinks.
the addition of berry powder
We added a scant 1/4 teaspoon of berry powder to enhance the drink’s color. Without it, the drink is still a beautiful blush pink, but we wanted to pump it up a little. It’s completely optional, but if you have freeze-dried strawberries or raspberries, you could add a few to the shaker.
We actually used Dragonfruit powder, which we bought just because it was so ridiculously pretty. It has a very mild flavor, but as a natural color enhancer, it’s amazing. It also makes a beautiful garnish when lightly dusted on top of the foam.
Additionally for garnishing the rhubarb gin sour, you could also use a thin strip of rhubarb, or just a sprig of mint, if you like.
Rhubarb Gin Sour
Ingredients
For one cocktail:
- 2 ounces good gin (we recommend London Dry style)
- 3/4 ounce homemade rhubarb syrup (see below)
- 1/2 ounce fresh lemon juice
- 1 egg white or 1.5 ounce aquafaba
- 1/4 teaspoon dragonfruit or other berry powder optional
- 2-3 dashes rhubarb or other bitters
- Ice
For garnish:
- A thin strip of rhubarb
- Small sprig of mint
- Tiny dusting of berry powder
Instructions
- Combine the gin, rhubarb syrup, lemon juice aquafaba/egg white, fruit powder (if using) and bitters in a cocktail shaker (no ice). Place the lid on and shake well to combine the ingredients, about 30 seconds.
- Add ice, replace the lid and shake vigorously for another 30 seconds.
- Double strain into cocktail glass, garnish as desired and serve.
Rhubarb Syrup
Ingredients
- 3 cups about 1 1/2 pounds roughly chopped rhubarb – the redder the better
- 1 1/2 cups water
- 1 1/2 cups sugar
- 1/4 cup freshly squeezed lemon juice
Instructions
- Add the rhubarb and water to medium saucepan and bring to a boil over high heat. Reduce heat to medium-low, cover, and gently simmer until very soft, about 15 minutes.
- Set a fine mesh strainer lined with a 2 layers of cheesecloth over a large heat-proof bowl. Carefully pour the rhubarb through the strainer. Gently press on the rhubarb with a spoon to expel as much liquid as possible. Discard the rhubarb pulp.*
- Return the liquid to the saucepan, add the sugar and turn heat to medium-high. Bring to a boil and cook until the sugar dissolves, about 2 minutes. Remove from the heat, stir in the lemon juice, and let cool to room temperature. If you want a very clear syrup, strain once again, then transfer into a container and refrigerate. Rhubarb Syrup will keep well in the refrigerator for up to a month.