Indeed My Heritage: Cinnamon-Rhubarb Jam With Agar Instead of Pectin

I hadn't canned much jam before experimenting with using agar instead of pectin. Actually, the only jam I did can was a few years back--some grape preserves, following the Ball (brand) canning book's directions for canning jams without added pectin. It was grape jam, and it was very sweet. That's because you have to add a lot of sugar if you're not using pectin, and boil it forever to boil it down and thicken it. After my friend Lori posted on her blog about using agar instead of pectin as a thickener, I was intrigued, and ended up on a merry summer-long adventure experimenting as different fruits ripened into season.

My rhubarb plants yielded a small amount (they're still getting established in my garden), and I didn't really know what to do besides rhubarb muffins--which were really good, by the way. I had already used my strawberries, so strawberry-rhubarb jam was no longer on the docket (although I could've used store-bought strawberries). When a friend gifted me with a bag of rhubarb, I knew I had enough to try using agar and making jam, but what to make?

I eventually found a recipe online (can't find it now; I should've pinned it to my Pinterest canning board!) for cinnamon-rhubarb jam. Working off that recipe, I made my own. The jam was very spreadable, and the sweetness of the sugar was balanced with the tartness of the rhubarb. I could probably get away with adding another teaspoon of agar to the recipe, but since this was my first attempt at using agar, I wanted to stick as closely as I could to the original recipe.

Agar powder bought at Fruitful Yield.

With agar, you don't have to worry about adding all the sugar as with a traditional recipe. For instance, Ball's canning book tells me to use 4 cups of strawberries/rhubarb and 5 1/2 cups of sugar. Whoa. Surely we can do better than that. And yes--we can!

Cinnamon-rhubarb jam on toasted sourdough bread.

Here we go with the recipe. I assume you've canned something before, so I won't go into the minutiae of preparing the canning pot and lids. Just enough so you remember to do it before preparing the fruit! Okay--here it is:

Cinnamon-Rhubarb Jam -- Using Agar Powder Instead of Pectin
Makes about six half-pint (8-oz.) jars.

6 cups rhubarb, rinsed and sliced
1 cup water
1/2 teaspoon butter (helps retard foaming)
4 tablespoons (1/4 cup) lemon juice
1 teaspoon cinnamon
2 cups sugar (or to taste)
3 tablespoons plus 1 1/2 teaspoons agar powder

Prepare canning pot, jars, and lids. Fill the pot with water, put it on the stove and get the burner started. It takes a long time to bring to a boil! I place my canning jars (thoroughly washed/rinsed) into a dishwashing tub and fill it with really hot water. My seals go into a bowl with boiling water poured on top. I replace the water if it cools off during the time I'm preparing the jam.

Tip: I use a large teakettle and boil water, leaving it on a simmer burner throughout the whole canning time. I'll use the water to replace cooled-off water on the seals, or to add to the canning pot if there's not enough water in it, or if too much boils out during the boiling time. Now it's on to the fruit part of the recipe.

Speaking of which, here's another tip: Rhubarb does not need to be peeled. Wash it, cut off the ends, and use a sharp knife to slice it up. That will help eliminate the stringy edges. Plus, when you boil the rhubarb, it softens, making it easier to blend.

Combine rhubarb and water in a saucepot; bring to a boil then simmer until soft. Puree. Bring to a boil again, stirring frequently, and add the rest of the ingredients except the agar. Mix until all ingredients are well-blended. Whisk in the agar, little by little, until it's all incorporated.

Note on whisking in agar powder!
The agar powder will clump together in lovely (being sarcastic there) jam-covered blobs if you simply dump it into the pot. Trust me (I say that a lot--it means I speak from experience). The powder is very fine, so you'll want to sprinkle a bit, whisk it in, sprinkle a bit, whisk it in... Until it's all incorporated. Whew. No worries, though--if you happen to get agar blobs, use a stick blender and attack the blobs. They'll blend in nicely. Trust me on this, too! :)

Once the agar is whisked in, continue to simmer the mixture, stirring constantly (get a helper, have a book handy, switch stirring arms, etc.) for 20 minutes. This helps the agar mix in and thicken (which it does at room temperature, so don't add extra agar thinking it's not thickening!).

At the 15-minute mark, you can test the thickness by spooning some jam into a small dish that you've placed in your freezer (do that when you start!). Wait 2-4 minutes, then run your finger through the mixture. Does it feel thick? It's probably good. My issue is that I think it's not thick enough, then add more agar, and once the canning is done, my jam is thick. Too thick. Still great for eating, though, in case you encounter this, too. So, if it feels even a little thick, it's probably good. You can add a little extra agar; maybe a teaspoon at most, sprinkling and whisking it into the mixture. But I warned you, so be careful! :)

Ladle hot jam into hot jars, leaving 1/4 inch headspace. I use a plastic ruler because I just can't seem to eyeball the short lengths correctly! Remove air bubbles (use plastic or glass knife or rod, not metal which will cool the mixture) and adjust headspace if necessary. Wipe rim of jars, place seal on top, and screw band down over seal until resistance is met, then increase to fingertip-tight.

Place jars in boiling water in canning pot (or place in canning pot insert, which is what I use, then lower the entire insert into the boiling water). Bring to a full, rolling boil with lid on, and let boil (must stay at full boil!) for ten minutes. Then, remove canning pot lid and wait five minutes. Remove the jars to a cooling rack. I simply carefully lift my canning pot insert straight up and out onto a large cutting board, then use my canning tongs to remove each jar to a cooling rack. Let cool 24 hours.

After cooling, check jars to make sure they sealed, and refrigerate any unsealed jars for immediate use. At this point, I gently wash each sealed jar in warm soapy water to remove residue left behind by the canning pot water (there is always some--even if it's lime from harder water). Then I dry the jars, label them, and store them in our Bomb Shelter (the affectionate name of our basement food pantry).

Here's the photo documentary, so you can see how things are done. Or, at least when I remembered to snap a photo of what I was doing!