Rhubarb Shrub
Rhubarb shrub is a simple drinking vinegar made with fresh rhubarb, sugar, and apple cider vinegar. After two to three days, the rhubarb releases a gorgeous pink syrup that's tart, lightly sweet, and perfect for sparkling water, cocktails, and vinaigrettes all season long.
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Rhubarb shrub is one of the easiest things you can make with spring rhubarb, and it starts with just a few ingredients and no cooking. Here’s how mine came to be.
When I bought my house several years ago, I went a little crazy planting things without a plan. A friend dropped by with a rhubarb plant she’d dug up from her yard, and I stuck it in the corner outside my kitchen window without much thought.
Every year since, those big dramatic leaves burst out of the ground with candy-red stalks. And every year, I’d wait for the leaves to wilt, yank the stalks out, and toss them in the compost bin. Rhubarb is resilient, it keeps coming back year after year, stronger and more beautiful. Finally, I decided to give it a higher purpose: making a rhubarb shrub.
What is a Rhubarb Shrub?
A shrub, also known as a drinking vinegar, is a sweetened, vinegar-based syrup used to flavor drinks. I first learned about shrubs a couple of decades ago at a farmers market, where a woman was selling about 20 different flavor combinations. I bought some, used it in a salad dressing or two, and left the rest to languish in the back of my refrigerator.
The irony is that shrubs actually last a very long time, they pre-date refrigeration entirely. A splash in sparkling water makes a homemade flavored water that’s one of the most refreshing things you can drink on a warm afternoon.
This rhubarb shrub is sharp and refreshing, more vinegary than you’d expect, but in the best way. The acidity is bright and forward, the rhubarb comes through clearly, and the sweetness is just enough to balance it out. Rhubarb is commonly paired with strawberry in desserts, so its standalone tart-and-floral flavor is somewhat difficult to describe. This shrub is a great introduction.
Ingredients You’ll Need
This recipe keeps it to these core ingredients:
- Rhubarb. Two cups of chopped fresh rhubarb, about four stalks. Garden rhubarb or farmers market rhubarb both work beautifully. The redder the stalks, the deeper and more vibrant the pink color of the finished shrub.
- Granulated sugar. One cup. The sugar draws the juice from the rhubarb through osmosis over two to three days, creating a naturally flavored pink syrup without any cooking required.
- Apple cider vinegar. One cup. Apple cider vinegar gives the shrub a mild, slightly fruity acidity that complements the rhubarb well. Red wine vinegar is a good alternative for a slightly deeper flavor and more vibrant pink color.
- Kosher salt. Just a few pinches to round out the sweetness and enhance the rhubarb flavor.
A note on rhubarb leaves: Rhubarb stalks are perfectly safe to eat, but the leaves are toxic, containing high levels of oxalic acid, and should be kept away from children and pets. The good news is they’re safe to compost, as the oxalic acid breaks down in the bin.
How to Make Rhubarb Shrub
Making a rhubarb shrub is mostly a waiting game, with minimal active time and a process that’s satisfying to watch unfold.
Combine rhubarb, sugar, and salt in a glass jar. A Weck jar or any wide-mouth glass jar works perfectly. Avoid metal lids throughout, as the sugar and vinegar added later can react with the metal over time. Secure the lid and give the jar a good shake.
Let it rest, then refrigerate. Leave the jar at room temperature until liquid begins to form, about two hours. Once you see liquid starting to appear at the bottom of the jar, transfer it to the refrigerator.
Stir once a day for two days. The sugar slowly draws the juice from the rhubarb, and within 24 hours you’ll see a gorgeous pink syrup forming.
Strain out the solids. By about the third day, the sugar should be completely dissolved and a vibrant pink syrup will have developed. Pour the mixture through a fine mesh strainer into a bowl or jar, pressing the spent rhubarb firmly against the strainer to extract every drop. The spent rhubarb solids are delicious stirred into yogurt or served over vanilla ice cream, though no judgment if they go straight to the compost.
Stir in the vinegar. Add one cup of apple cider vinegar to the strained syrup and stir gently to combine. Taste it, it should be tart, bright, and just sweet enough.
Store in sealed glass jars or bottles. Again, be sure to avoid metal lids to avoid any reaction from the vinegar. The finished rhubarb shrub keeps for several months.
How to Use Rhubarb Shrub
The simplest way is to pour about two tablespoons in a glass over ice and top it with sparkling water. That’s it. You’ll notice in the picture below that the vibrant pink will look diluted, but the flavor is still floral, slightly sweet, and better than any artificially flavored sparkling water.
If you enjoy making fresh-fruit syrups for drinks, my cherry limeade syrup follows a similar approach and is just as easy to keep on hand all summer.
A few other ideas to use your shrub:
- Use it as a cocktail mixer. Stir a splash into a gin and tonic or vodka soda, or use it in place of simple syrup in other cocktails. It also works as an added splash of flavor for my raspberry lemon sparkler or any lemonade drink.
- Replace acid in salad dressing. Whisk a tablespoon into a vinaigrette in place of your usual acid, like citrus juice or plain vinegars. It pairs especially well in a strawberry vinaigrette.
Recipe Tips and Suggestions
- Use a glass jar with a non-metal lid. Vinegar reacts with metal over time, affecting the flavor. A Weck jar, mason jar with a plastic lid, or any glass container with a tight-fitting non-metal lid works well.
- The redder the rhubarb, the pinker the shrub. Deeply red stalks produce a vibrant, jewel-toned syrup. Green-heavy rhubarb will still taste great but the color will be more muted.
- Don’t skip pressing the solids. The spent rhubarb holds a surprising amount of liquid. Press it firmly against the strainer to maximize your yield.
- Taste and adjust before bottling. Every batch of rhubarb varies in sweetness and tartness. Adjust with a small amount of simple syrup or a splash more vinegar as needed.
- Make a double batch. The shrub keeps for several months and disappears faster than you’d expect.
Rhubarb Shrub
Ingredients
- 2 cups rhubarb, chopped into ½-inch pieces, about 3 to 4 stalks
- 1 cup granulated sugar
- 2-3 pinches kosher salt
- 1 cup apple cider vinegar, or red wine vinegar
Instructions
- Chop rhubarb into ½-inch pieces and layer in a wide-mouth glass jar with sugar and salt. Secure the lid and give the jar a good shake.
- Let the jar rest at room temperature until liquid begins to form, about 2 hours. Once liquid starts to appear, transfer the jar to the refrigerator.
- Stir once daily for the next 2 days. The sugar will slowly draw the juice from the rhubarb, creating a vibrant pink syrup.
- On day 3, strain the mixture through a fine mesh strainer, gently pressing the solids to extract all liquid.
- Stir in 1 cup apple cider vinegar. Transfer to glass jars or bottles with plastic lids. Refrigerate and use within several months.
Notes
- To serve: Add 2 tablespoons of rhubarb shrub to a glass of ice and top with sparkling water. Garnish with fresh mint if desired.
- Storage: Use a glass jar with a non-metal lid throughout the process. Vinegar reacts with metal over time.
- Choose vibrant stalks: The redder the rhubarb stalks, the more vibrant the pink color of the finished shrub.
- Vinegar choice: Red wine vinegar gives a slightly deeper flavor and more vivid pink color than apple cider vinegar.
- Safety note: Rhubarb stalks are safe to eat, but the leaves are toxic. Keep them away from children and pets. The leaves are safe to compost.
- For a cocktail: Stir 2 tablespoons of shrub into a gin and tonic or vodka soda, or use in place of simple syrup.
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