Local cherry season is so fleeting that you can easily miss it. Every year, I pounce on the opportunity to harvest the first sweet cherries, followed a week or so later by sour cherries. Sour cherries – an annual staple for my jam making – are in short supply so far but I have liberal amounts of sweet cherries. Longing for the tartness that makes the sour type legendary, I decided to add roasted rhubarb and recreate the tang. Success!
Unlike softer fruits such as strawberries and raspberries that are macerated in sugar in proportion to weight (I use 1 unit of sugar to 2 of fruit, or sometimes 2:3), cherries as well as blueberries can be cooked first and sugar added according to volume (I use 3 units of sugar to 4 of fruit puree, sometimes less). After a second round of cooking with the sugar, the cherries are set aside for a few hours (or longer in the refrigerator). The reason is both to allow the fruit to plump and to allow pectin to develop, since I cook the cherries from the outset with lemon juice, and seeds and a little rind tied in a muslin sack. This helps create the characteristic gel and keeping you from overcooking the jam in its final stage.
I made this jam with roasted rhubarb since I thought it would add tartness, but you could simply add sliced rhubarb to the cherries in the second stage of cooking. Roasted rhubarb would be added in the third or final stage. I left some of the cherries whole, pureeing the rest, since I wanted a chunky jam. You can adjust the texture by chopping the cherries to varying degrees of fineness.
Sweet Cherry and Roasted Rhubarb Jam
2 lbs sweet cherries, pitted (yielding about 4 cups)
Sugar (around 1½ c, to be measured)
3 stalks red rhubarb, sliced
Optional: 3 tbsp brown sugar for roasting
Reserve about a cup of whole cherries and coarsely chop the rest. Pour all the cherries into a large saucepan.
Peel the lemon, leaving the pith intact. Juice the lemon, reserving the seeds. Place the lemon peel and seeds in a small muslin sack. Add the lemon juice and the muslin bag to the cherries.
Bring the cherries to a boil over medium-high heat, stirring to avoid scorching them, and cook for about 5 minutes or until the cherry flesh is completely soft and the juice has been rendered. The cooking time may vary based on the variety and ripeness of the cherries.
Remove the muslin sack and pour the cherries and their liquid into a large measuring cup (mine yielded 2 cups.) Add ¾ of that amount (for me 1½ c) of sugar and return the mixture, including the muslin sack, to the saucepan. Add sliced raw rhubarb at this point, unless you’re roasting it, in which case, it will be added later.
Bring the mixture to a boil and cook, stirring to dissolve the sugar, for about 5 minutes. Remove from the heat, pour into the measuring cup, cover with parchment paper (love that trick from Christine Ferber), and, once cooled, let sit for 6 hours or overnight in the refrigerator. The parchment paper keeps the cherry juice from evaporating while allowing the mixture to breathe. If your refrigerator has odorous contents, cover the bowl with plastic wrap.
If you are adding roasted rhubarb to the jam, cook sliced rhubarb tossed with brown sugar in a 350-degree oven until it collapses and starts to caramelize, about 5 minutes. Add it to the cherry mixture.
Prepare jars and lids for water bath canning (boil then submerged in water by one inch and keep them hot.). Place a saucer in the freezer for testing the gel. Get a small pan of water ready to boil for sterilizing the lids.
Bring the cherry and rhubarb mixture to a boil in a large wide heavy pan over medium-high heat and continue to cook until gelled. Mine set in about 5 minutes. Test the gel on the frozen saucer by placing a drop on the plate and patting it with your finger. If it wrinkles, it’s gelled.
Set the pan aside off the heat for a few minutes until the foam subsides. Remove the muslin sack and skim the foam. Meanwhile, bring the small pan of water to a boil, add the flat lids and turn the heat off.
Ladle the jam into the prepared (hot) jars, clean the rims thoroughly, cover with the two-part lid, and process in a water bath canner for 10 minutes after the water boils. Turn off the heat, remove the canner lid and let sit for 5 minutes before removing to a counter to cool undisturbed.
Makes approximately 6 four-ounce jars.