Rhubarb Facts

Rhubarb has been cultivated and used for millennia. Originating in Asia, its roots have been used in Chinese medicine for thousands of years.

Like many products (including ice cream), rhubarb came to Europe along the silk road through the travels of Marco Polo. While its leaves are toxic to humans (due to high levels of oxalic acid), its stalks have many healthful properties. Rhubarb is high in antioxidants, specifically anthocyanins (which give it its red color) and proanthocyanidins. Some consider rhubarb a “miracle food,” due to the anti-bacterial, anti-inflammatory, and anti-cancer properties of its antioxidants. Rhubarb is also high in dietary fiber, vitamin C, vitamin K, calcium, potassium and manganese.

Biologically a vegetable, rhubarb was officially classified as a fruit by the US Customs Court in 1947 to lower import tariffs. Since then, the plant has rightly regained its status as a vegetable, even though it is mostly used like a fruit in the American kitchen. Used in savory dishes in other parts of the world, rhubarb is primarily used in desserts in the US, requiring copious added sugar.

While rhubarb does grow exuberantly on its own, it grows better in full sunlight. It’s also hungry. Well fertilized and in full sun, rhubarb patches can be waist and even chest-high. To harvest the stalks properly, pull gently from the base of the stalk. Some advocate for harvesting all the stalks at the same time, which gives the plant plenty of sun to regenerate itself. Whatever your method, you should get two to three harvests from your rhubarb plant throughout the summer months in Alaska, depending on local weather patterns.

I think rhubarb should be Alaska’s signature crop, exported around the globe.

How to prepare rhubarb

Most people use rhubarb stalks cut into chunks and then baked or cooked. My favorite way to use the plant is by juicing it fresh. Rhubarb stalks are 90% or more water by weight. The secret to capturing rhubarb juice is to break down the plant’s cell walls. You can do that manually with a fruit press, but it works even better if you freeze and thaw the stalks first. The freeze/thaw process weakens the plant’s cellular structure and allows its juice to flow freely. You may find recipes that have you cook the stalks in water to release the juice. We feel that this can impart a cooked, jam-like taste to the juice. We prefer using the freeze/thaw method because you can capture a lot of juice while retaining rhubarb’s full brightness.

In our cafe, we used a bladder press, a piece of equipment normally used in wine-making. After freezing and thawing the stalks, we would add them to the press. The magic of water pressure filled the press’s internal bladder and mashed the stalks against the rim of the press, producing brilliantly red, pure rhubarb juice. After pressing out the liquid, we pasteurized it and stored it for later use. Each summer, we processed thousands of pounds of stalks, grown in gardens throughout Southeast Alaska. We offered store credit to locals who bring in their rhubarb stalks, trading their harvest for ice cream cones and cappuccinos.

You can juice rhubarb yourself, too, with only a freezer, a fridge and a simple colander. Take your stalks and chop them into one or two inch chunks. Freeze them solid in a ziploc bag. After freezing them, thaw them in the bag overnight in the fridge. Once thawed, pour the chunks and the collected juice through a colander set inside a bowl. Mash the stalks to get whatever juice you can out of them. You won’t get as much juice as you would in a juice press, but you’ll get plenty!

Rhubarb Sorbet Recipe

This recipe came in a close second to our sherbet in terms of popularity. It has a bright rhubarb taste with none of the dairy to mute the flavor. Corn syrup (not the controversial high fructose variety) is a required ingredient here. In sorbets, you need something like corn syrup or honey to provide body, in place of the cream and milk normally present in ice cream. We used corn syrup solids in our cafe, which is simply the syrup with the water removed.

It’s also helpful to use a stabilizer to add creaminess to the sorbet. Stabilizers primarily prevent the growth in ice crystals, both in ice cream and sorbet. Through this action, they create a smoother sorbet texture and result in a creamier mouthfeel. Most of our sorbet recipes used a combination of guar gum and gum arabic. These stabilizers are easy to use because they activate at cold temperatures. Here we use pectin, however, as it’s readily available in most supermarkets. Pectin and some other stabilizers like locust bean gum are heat-activated. Hence the step required in this recipe to heat the mixture.

INGREDIENTS

• 8 c rhubarb stalks, frozen and chopped

• 1 c sugar

• ¼ c light corn syrup

• 1 t pectin

• ⅛ t kosher salt

• ½ t balsamic vinegar

• 1 t lemon juice

INSTRUCTIONS

1. Overnight, thaw rhubarb stalks in refrigerator.

2. Place colander or sieve into bowl. Mash rhubarb into colander, capturing juice in bowl. You should have at least 3 cups of juice, depending on the quality of the rhubarb.

3. Combine the 1 cup of rhubarb juice, pectin, and salt in a medium saucepan.

4. Heat over high heat, stirring occasionally, until pectin dissolves, about 5 minutes. Continue heating until reaching a full boil.

5. Remove from heat, and stir in sugar and corn syrup until dissolved.

6. Add remaining two cups of rhubarb juice to mixture, along with balsamic vinegar and lemon juice.

7. Separate one cup of mixture and cover with plastic wrap and freeze solid.

8. Place rest of mixture in container, cover with plastic wrap and chill in fridge until mixture reaches 40F.

9. Remove mixtures and stir frozen portion into rest of mixture until fully dissolved.

10. Transfer mixture to ice cream machine and churn until mixture has consistency of thick milkshake and color lightens, 15 to 25 minutes.

11. Cover, and freeze for at least 4 hours (preferably overnight).