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This blackberry rhubarb jam recipe is the kind of kitchen project that makes you feel instantly at home. Tart rhubarb and sweet, juicy blackberries simmer down into a jam that’s rustic, vibrant, and packed with flavor. If you’ve never made jam before, don’t worry, it’s easier than you think, and the reward is jars of jewel-toned goodness you’ll want to spoon onto everything. Whether you prefer old-fashioned blackberry rhubarb jam with pectin, a low-sugar version, or even one made with honey, I’ll walk you through step by step. You’ll also find helpful tips for storage, serving, and flavor twists.
In this Article
Key Takeaways: What You Need to Know
- Blackberry rhubarb jam balances tart and sweet flavors naturally, no need to drown it in sugar.
- You’ll need about 4 cups rhubarb + 3 cups blackberries for a standard batch.
- You can make this jam with or without pectin, depending on how firm you want the set.
- Honey or reduced sugar versions work beautifully if you prefer a lighter jam.
- Rhubarb’s natural acidity makes this jam safe for canning with standard USDA guidelines.
- This jam doubles as a filling for rhubarb bread or as a swirl in rhubarb muffins.
Do rhubarb and blackberries go together?
Absolutely. The tart bite of rhubarb pairs beautifully with the deep, sweet flavor of blackberries. This blackberry rhubarb jam recipe captures that balance in every spoonful. When I was growing up, my mom would stir together whatever fruit was in season, and rhubarb was always the backbone. Adding blackberries gives the jam a bold purple hue and layers of flavor that plain rhubarb jam just can’t match.
My Story Behind Blackberry Rhubarb Jam
Every June here in Texas, farmers’ market tables start overflowing with blackberries, plump, glossy, and begging to be baked, canned, or eaten by the handful. Pair that with rhubarb (which usually peaks just before), and you’ve got a match made for jam jars.
I started making this blackberry rhubarb jam about a decade ago, after a neighbor shared her old-fashioned recipe. She didn’t use measurements, just a big enamel pot, rhubarb from her garden, and baskets of berries we picked together. We boiled it down until the kitchen smelled like summer itself. That first spoonful, tart, sweet, and just a little rustic, sealed the deal.
Now, I make several batches each year, some with pectin for firm spreads and some without for a looser, rustic jam. A jar always goes into my fridge, and the rest get tucked into the pantry for when I need a taste of sunshine in winter.
What is rhubarb berry jam?
At its simplest, rhubarb berry jam is a preserve made by simmering rhubarb with sugar and any type of berries, strawberries, blueberries, raspberries, or, in this case, blackberries. Rhubarb brings a sharp tang, while the berries provide depth and sweetness. It’s a flexible base recipe, and this version highlights how blackberries add richness and color.
For another twist, try my strawberry rhubarb jam or peach rhubarb jam. Each has its own personality, but the blackberry pairing is especially bold.
Step-by-Step Blackberry Rhubarb Jam Recipe (With and Without Pectin)
How to make blackberry and rhubarb jam?
This blackberry rhubarb jam recipe is flexible. You can make it with pectin for a firmer, quicker set or without pectin for a softer, more old-fashioned jam. Both are delicious, and both use just a handful of ingredients.
Below is my base recipe, perfect for beginners but flavorful enough for seasoned jam-makers.
Blackberry Rhubarb Jam Recipe
| Ingredient | Amount | Notes |
|---|---|---|
| Fresh rhubarb (chopped) | 4 cups (about 1¼ lbs) | Use firm stalks, no leaves |
| Fresh blackberries | 3 cups | Rinse and gently pat dry |
| Granulated sugar | 3 cups | Adjust for sweetness (2½ cups for less sweet) |
| Lemon juice | 2 tbsp | Adds acidity and helps set jam |
| Pectin (optional) | 1 packet (1.75 oz) | Use only if making the with-pectin version |
| Honey (optional) | ½ cup | Use in place of some sugar for variation |
Instructions (With Pectin)
- Prep fruit: Chop rhubarb into small ½-inch pieces. Mash blackberries lightly with a fork or potato masher.
- Combine: Place rhubarb, blackberries, and lemon juice in a large pot. Add pectin and stir well.
- Boil: Bring mixture to a rolling boil over medium-high heat, stirring often.
- Add sugar: Stir in sugar all at once. Continue stirring until dissolved.
- Final boil: Boil hard for 1–2 minutes, then remove from heat.
- Jar: Ladle hot jam into sterilized jars, leaving ¼ inch headspace. Wipe rims, seal, and process in a boiling water bath for 10 minutes.
Instructions (Without Pectin – Old Fashioned)
- Cook down: Place rhubarb, blackberries, sugar, and lemon juice in a heavy-bottom pot. Stir well.
- Simmer: Cook over medium heat, stirring often, for 30–40 minutes until thickened. Skim foam if needed.
- Jam test: Place a spoonful of jam on a chilled plate. If it wrinkles when pushed, it’s ready.
- Jar: Pour hot jam into sterilized jars. Seal and process in a boiling water bath for 10 minutes.
How do you make low sugar rhubarb jam?
For a lighter blackberry rhubarb jam recipe, reduce sugar to 2 cups and add ½ cup honey. Honey adds natural sweetness and complexity, while still keeping the jam safe to preserve.
Another option is to use low-sugar pectin (like Sure-Jell Light). This allows you to cut sugar by 40–50% without affecting set.
Can you make rhubarb jam with honey?
Yes! Replace up to half of the sugar with honey in this recipe. Honey gives the jam a warm, floral flavor that pairs perfectly with blackberries. Just avoid replacing all of the sugar, since sugar is crucial for the jam’s structure and shelf life.
Pro Jam-Making Tips
| Tip | Why It Matters for Blackberry Rhubarb Jam |
|---|---|
| Use a wide pot | A shallow surface area speeds evaporation and thickening. |
| Stir constantly | Prevents scorching on the bottom of the pot. |
| Chill test | Always test jam on a cold plate to check set. |
| Don’t skip lemon juice | Rhubarb is acidic, but lemon ensures safe canning. |
Tips for Perfect Blackberry Rhubarb Jam Every Time
How do you make sure blackberry rhubarb jam sets properly?
The key to a successful blackberry rhubarb jam recipe lies in understanding how fruit, sugar, and acid work together. Rhubarb is naturally acidic, which helps, but it doesn’t have much pectin. That’s why adding blackberries is so brilliant, they naturally contain more pectin and help the jam thicken without needing a ton of additives.
Still, set can vary. If your jam is too runny, don’t panic. Just re-boil with a little added pectin or let it cook down longer.
Top 6 Tips for Blackberry Rhubarb Jam Success
| Tip | Why It Matters |
|---|---|
| 1. Measure fruit by cups, not weight | Rhubarb and blackberries release different amounts of liquid. Cups give more consistency. |
| 2. Use lemon juice | Adds acid that helps preserve color, flavor, and shelf life. |
| 3. Don’t skimp on sugar | Sugar preserves the jam and helps it gel. Even in low-sugar recipes, some sugar is essential. |
| 4. Use the “wrinkle test” | Spoon jam onto a cold plate. If it wrinkles when pushed, it’s ready. |
| 5. Stir constantly | Rhubarb and berries burn easily. Stirring prevents scorching. |
| 6. Let jars cool undisturbed | This ensures a proper seal after water-bath canning. |
What if my jam is too runny?
If your blackberry rhubarb jam doesn’t set:
- Option 1: Re-boil with 1 tablespoon powdered pectin mixed with ¼ cup sugar.
- Option 2: Cook longer. Keep at a steady boil until it reaches 220°F (the jam stage).
- Option 3: Enjoy it as a sauce! Looser jam is perfect for topping strawberry rhubarb cobbler or spooned over yogurt.
What flavor variations can you try?
Once you master this blackberry rhubarb jam recipe, it’s easy to experiment:
| Variation | What to Add |
|---|---|
| Spiced Jam | Add ½ tsp cinnamon + ¼ tsp nutmeg |
| Citrus Twist | Add zest of 1 orange or lemon |
| Vanilla Jam | Stir in 1 tsp vanilla after cooking |
| Honey Blend | Replace 1 cup sugar with ½ cup honey |
| Berry Mix | Swap half blackberries for blueberries or raspberries |
These tweaks transform the jam into something new every time you make it.
Small-Batch Blackberry Rhubarb Jam
Want just a jar or two? Halve the recipe:
- 2 cups rhubarb
- 1½ cups blackberries
- 1½ cups sugar
- 1 tbsp lemon juice
Cook until thickened and store in the fridge for up to 3 weeks.
Storage, Serving & Real-Life Blackberry Rhubarb Jam Review
How do you store blackberry rhubarb jam?
Once your blackberry rhubarb jam recipe is finished, proper storage keeps it tasting fresh and safe. Here’s how I store mine:
- Pantry (12–18 months): If you’ve processed the jam in a boiling water bath, sealed jars can be stored in a cool, dark pantry for up to a year and a half.
- Fridge (3–4 weeks): An opened jar should go straight into the refrigerator. Use within a month.
- Freezer (6 months): You can freeze jam in freezer-safe containers. Leave at least 1 inch of headspace to allow for expansion.
Always check seals before using, and discard if you see mold, leaks, or broken seals.
What are the best ways to serve blackberry rhubarb jam?
This blackberry rhubarb jam recipe isn’t just for toast. Its sweet-tart balance makes it versatile:
- Spread on warm biscuits or homemade rhubarb bread
- Swirled into plain yogurt for a quick breakfast
- As a glaze for grilled chicken or pork (yes, savory works!)
- A filling for strawberry rhubarb bars
- Spooned over ice cream for a rustic sundae
For gatherings, I love pairing this jam with soft cheeses like brie or cream cheese. It’s always the first jar to disappear on a cheese board.
Real Reader Review:
“Abby, I made your blackberry rhubarb jam with honey, and it was the best jam I’ve ever canned. The color was deep purple, and the flavor had that tart-sweet balance you always talk about. My kids ate it on waffles before the jars even cooled. Definitely making a double batch next summer!”
— Hannah R., Round Rock, TX
Personal stories and real-life results remind me why I love sharing recipes. This jam is about more than food, it’s about making something that feels like a little gift every time you open a jar.
What are the instructions for cooking rhubarb jam?
At its core, cooking rhubarb jam (whether plain or with berries) always follows three steps:
- Combine fruit, sugar, and lemon juice in a large pot.
- Simmer until fruit softens and juices release.
- Cook at a steady boil until thickened or pectin is activated.
That’s the foundation. Whether you’re making this blackberry rhubarb jam recipe or my classic rhubarb jam recipe, the principle is the same.
Blackberry Rhubarb Jam Recipe
Ingredients
Equipment
Method
- Chop rhubarb into small pieces and mash blackberries lightly.
- Place rhubarb, blackberries, and lemon juice into a large heavy pot.
- With pectin: Stir in pectin, bring to a rolling boil, add sugar all at once, boil hard for 1–2 minutes, then remove from heat.
- Without pectin: Add sugar and cook over medium heat, stirring often, until jam thickens (30–40 minutes). Test by spooning jam on a chilled plate, if it wrinkles, it’s ready.
- Ladle hot jam into sterilized jars, leaving ¼ inch headspace.
- Wipe rims, seal, and process jars in a boiling water bath for 10 minutes.
- Let cool undisturbed for 3 hours. Store sealed jars in pantry for up to 1 year.
Nutrition
Notes
Tried this recipe?
Let us know how it was!FAQ – Blackberry Rhubarb Jam Questions Answered
Do rhubarb and blackberries go together?
Yes, rhubarb and blackberries pair beautifully. Rhubarb adds tart brightness, while blackberries provide sweetness and depth. This balance makes a blackberry rhubarb jam recipe both refreshing and rich in flavor.
What is rhubarb berry jam?
Rhubarb berry jam is a fruit preserve made by simmering rhubarb with sugar and berries. The berries add sweetness and color, while rhubarb gives a tangy kick. A blackberry rhubarb jam is one of the boldest versions, with a deep purple color and sweet-tart flavor.
How to make blackberry and rhubarb jam?
To make blackberry rhubarb jam, combine chopped rhubarb, blackberries, sugar, and lemon juice in a pot. Simmer until thickened or add pectin for a quicker set. Pour into sterilized jars and process in a boiling water bath for safe storage.
How do you make low sugar rhubarb jam?
For a lighter jam, reduce sugar to 2 cups and add ½ cup honey. You can also use low-sugar pectin, which allows the jam to thicken with less sugar. This keeps the blackberry rhubarb jam recipe bright and tangy without being overly sweet.
Can you make rhubarb jam with honey?
Yes, you can replace up to half the sugar with honey. Honey adds floral notes and natural sweetness. However, don’t eliminate all sugar, it helps the jam set and preserves shelf life. A honey blend works perfectly in this blackberry rhubarb jam recipe.
What are the instructions for cooking rhubarb jam?
The steps are simple: place rhubarb, berries, sugar, and lemon juice in a large pot. Simmer until fruit softens, then boil until thickened or pectin sets the jam. Pour into sterilized jars and process in boiling water. That’s the core method for any rhubarb jam recipe.
