Rhubarb Means Spring!

canning rhubarb

Canning up some rhubarb is a fantastic way to celebrate the arrival of spring. No, really it is!

So in celebration of SPRING, today I cover lovely rhubarb and answer the following…

  • What is it exactly? (Don’t believe what the government tells you)
  • What’s the pH level? (Can we really water bath process it?)
  • What’s my favorite recipe for using it up? (Trust me, it’s delicious!)

preserving rhubarb

Here in Southern California, Rhubarb can be found at a handful of farmer’s markets right now. I don’t grow it myself. Why? Because it tends to take up quite a bit of real estate in my tiny homestead. Plus, I found that with my warm winters, I do not have the chill factor needed to give it a good depth of flavor.

However, up north we grow it at the 1892 farmstead with great results. So if you can, I highly recommend growing it yourself. You can even try some of the fun varieties like ‘Valentine’ or ‘Giant Cherry’. But here in my 1/10th of an acre homestead, I rely on my local farmers to provide it at peak flavor.

So Is Rhubarb a Vegetable or Fruit?

No, that is not a stupid question. A lot people ask this. Traditionally rhubarb is used in pie and desserts. Not too many veggies do THAT. It has a tangy, bitter taste on its own and requires quite a bit of sugar to bring out its delicious nuances.

But even though rhubarb is used for its “fruit like” qualities it is not a fruit. Botanically speaking, it is 100% vegetable. We are consuming the leafstalk (just as we do with celery) and it has none of the botanical requirements for being a fruit. But just to confuse matters, awhile back the U.S. Customs Court classified rhubarb as a fruit in order to get lower import duties on it. Don’t let that confuse you.  Scientifically, rhubarb is a vegetable through and through.

rhubarb syrupCan We Water Bath Can Rhubarb?

As a canner, you probably hear over and over that you should never water bath process a vegetable that is not “pickled” or you run the risk of botulism. And if you follow me at all, you know I say this all the time. So what about rhubarb? People can it as jam, jelly, pie filling ALL the time and I just said it was a vegetable!…What gives??

Here’s the deal:

The thing that determines if you can or cannot water bath can ANYTHING is the pH of that food. That is the bottom line. In most cases (like 98% of the time), vegetables fall into the pH level of a low acid food and they cannot be water bath processed unless they are pickled or placed in vinegar so that their pH is safe. In other words, most veggies must be pressure canned. On the other end, fruits are considered high acid foods (with a pH below 4.6) and that “high acid” keeps their pH in the safe zone for water bath canning.

But rhubarb is a special case.

Rhubarb is the only vegetable I know of that is treated as a fruit, has “fruit-like” qualities AND has a pH in the “safe zone” (just like a fruit). I guess rhubarb SO wants to be a fruit, it even has the pH of a fruit!

So the bottom line is that with a pH of 3.1, rhubarb can be safely water bath canned. Lucky us! Also note that most canned rhubarb recipes also include lemon juice in the recipe. This is for two reasons: First as added security for keeping the acidity in the safe zone and second, to add brightness to the flavor. A little lemon will add zing to balance the sugar needed to offset the rhubarb tang.

To learn more about pH and water bath canning safety, visit my post on pH and Canning over at my TV Canning Blog.

BUT…Isn’t Rhubarb Toxic?

Well…yes. But only the LEAVES are toxic because they have very high levels of oxalic acid. Unless you have a very high sensitivity to oxalic acid, the stalks of rhubarb are perfectly safe to eat. This is why you always see the leaves cut off the stalks at the super market. If you grow them yourself, don’t eat the leaves! Only eat the stock.

Preserving Rhubarb

There are lots of ways to put up rhubarb. You can make a jam, pie filling or combine it with other fruits such as strawberries to create something unique. Keep in mind that rhubarb is not high in pectin, so most jam recipes combine with other fruit (like strawberries) or include a commercial pectin to get the gel.

But by far, my favorite thing to do with rhubarb is make a simple syrup.

Yep. It is fast, easy and makes the most incredible syrup EVER. I use the syrup in cocktails, sweet ice tea and I drizzle it over ice cream or other desserts. It is pure heaven in a bottle, I swear.

Here is a link to my rhubarb syrup recipe (with video!) over at my canning blog for our TV show.

Rhubarb Syrup Recipe


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About the Author

Theresa Loe is the Co-Executive TV Producer and the On-Air Canning/Homesteading Expert for the national PBS gardening TV series, Growing A Greener World. She is a lifetime canner and a graduate of the Master Food Preserver Program. She studied both sustainable horticulture and professional culinary arts and she is a wrangler of chickens and two teenage children. (Not necessarily in that order.)

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