Canning Rhubarb – How To Easily Can Your Own

Last updated: July 23rd, 2021

I love Rhubarb. I love that it is like a sour patch kid if you eat it right off the stem and I love that it is ready to harvest so early in the growing season. I also LOVE rhubarb sauce (and muffins) Grandma Inez had made all while I was growing up. I have a very big family so a pot of sauce didn’t last very long around her house. She would make it on a Saturday afternoon and let it sit till ‘coffee time’ after our weekly meeting for sauna (I’m Finnish). Now, I have moved away from my family and have no sauna but I still love the sauce!

How You Can Easily Can Rhubarb

Rhubarb season is short. Very short, so the best thing you can do for such season fruit and veggies is canning. But the question is always: how best to prepare the rhubarb for canning?

Before you even start canning, you need to prepare and cook the rhubarb for either eating on the spot or canning later :>

The following is what I came up with to can this delicious treat! Starting with small batches, which make for easier consumption later on. That way you can have a little or a lot (more batches/cans) depending on your needs.

Small batch preparation:

Quantity: Yields about 4 pints

What you need

• 4 cups rhubarb
• 1 ½ – 2 cups sugar (depending on tartness)
• Water
• 2 Tablespoons cornstarch

Cleaning Rhubarb:

Most importantly – Do NOT eat the leaves. They are poisonous.

Simply cut at base by the ground and cut the head (leaf) off. Soak in sink full of water to shake all the dirt off. Cut into bite size pieces or alternatively freeze or eat fresh rolled in sugar if you just can’t help yourself!

The Steps

1. Simply put your fresh or frozen rhubarb (cleaning instructions below) into a pot. P
2. Put enough water to cover rhubarb plus ½-1 inch.
3. Bring to a bubble and then turn to a low simmer.
4. Stir regularly to help break up the big pieces.
5. After about 1 hour on very low simmer start adding sugar. I always us my 1/3 cup measuring cup and add 1 at time. Stir sugar in fully till dissolved.
6. Cook for 5-10 minutes in between adding each round of sugar. Start tasting after about 2/3 cups sugar is added. When desired sweetness is reached cook for about 5 minutes to ensure all is dissolved and then turn heat to medium to bubble.
7. Your mixture should be pretty thin at this point. If it is thick- you are done cooking! If it is thin- add 2 tablespoons of cornstarch to 1 cup of water and stir in ½ to boiling rhubarb sauce.
8. Stir continuously till a boil is back. Continue this process till you like what you see.
9. Cool sauce. Get the ice cream out and enjoy. I eat mine straight up!

Canning Process

This process is somehow the most time consuming I find. So, I break it into a few steps.

Preparing The Jars

I like to prepare my jars beforehand and inspect them all to ensure they are usable. Jars with nicks or cracks around the top I throw away as they won’t seal or last.

I also inspect the rubber seals if I am using that type of jar and replace where necessary. They become brittle or cracked over time and you want to make sure they are good to go up front.

Heating the Jars & Lids

If you don’t have experience with this I recommend reading some other more specific posts on the process (just Google it) but here is the gist of what I do.

1. I preheat the oven to 130C/275F and place the jars in on a tray, ensuring they are not touching
2. I leave them in there for at least 20 minutes while starting the rest of the rhubarb prep.
3. I put all the lids in a boiling water bath and leave for a while, say 10 minutes, to ensure they are sterile. This I do a bit later just before I do the filling of the jars.
4. Dry the lids on a towel ready for filling the jars.

Filling The Jars

A few things before I get into the exact process. This is very hot work and you should be very careful when filling the jars. I use over mitts to handle them the whole time and ideally have someone help fill them. Also, you want both the rhubarb and jars to both be relatively hot when doing it. Adding cold ingredients to a hot jar will explode it – trust me, I did it once with a sirup and it was not fun! BOOM! glass everywhere.

Here are the steps I take:

1. Remove the jars a few at a time from the oven.
2. Fill each with a ladle (dipping the base tip just back in the liquid stops drips) and using a funnel helps keep the jar clean and sterile.
3. Leave 1/2 inch headspace in each jar.
4. Put the lid on asap after filling, pushing down on the center to pop the air out. (They should all pop back up eventually later)

The cleanliness and sterility of this process is not to be underestimated. If you don’t take care about the jars, lids, edges etc along the way (especially when using sugar) it is very easy to get mould in your jars later on. Trust me, I have experienced this too!

Storing The Jars

Store your jars in a cool dry place if it’s for long term storage. You can keep a few handy if you are going to use them in the near future. And maybe one in the fridge as a reward for all the hard work you just did.