Keto Sugar Free Rhubarb Jam

Here is my favorite sugar-free rhubarb jam recipe, with tangy rhubarb pieces, monk fruit sweetener for zero sugar, a touch of lemon juice, and just a pinch of salt to bring out all the flavors.

This rhubarb jam is perfect for anyone watching their sugar intake but still craving that sweet, tangy spread on their morning toast. I love making a few jars at a time so we always have some in the fridge. Nothing better than homemade jam without the sugar crash, right?

What Kind of Rhubarb Should I Use?

Fresh rhubarb is your best bet for making jam, and you’ll find it at most grocery stores during spring and early summer. The color of the stalks can range from green to deep red, but don’t worry – the red stalks aren’t any sweeter than the green ones, they just look prettier in the final jam. If fresh rhubarb isn’t available, frozen rhubarb works just fine too, though you may need to cook it a bit longer since it releases more water. Just make sure to always trim off and discard the leaves if you’re using fresh rhubarb from the garden, as they’re toxic and shouldn’t be eaten.

Options for Substitutions

This simple jam recipe works well with a few different swaps if you need them:

• Sweetener: You can use any sugar-free sweetener you prefer – erythritol, monk fruit, stevia, or allulose all work. Just keep in mind that stevia is much sweeter, so you’ll need less (start with 2-3 tablespoons and taste as you go). If you’re not avoiding sugar, regular granulated sugar works perfectly too.
• Rhubarb: Fresh rhubarb is best for this recipe, but frozen works in a pinch. If using frozen, thaw it first and drain any excess liquid before cooking to avoid a watery jam.
• Lemon juice: Lime juice makes a good substitute and adds a slightly different citrus note. You could also use apple cider vinegar if that’s what you have on hand.
• Red food dye: This is totally optional and just for color. You can skip it entirely, use natural alternatives like beet juice, or add a handful of strawberries or raspberries to the mix for natural color and extra flavor.

Watch Out for These Mistakes While Cooking

The biggest mistake when making sugar-free rhubarb jam is skipping the overnight maceration step, which draws out the natural juices from the rhubarb and helps create that thick, jammy consistency without added pectin.

Another common error is cooking the jam at too high of a heat once it’s boiling – after the initial boil, make sure to reduce to a gentle simmer or you’ll end up with mushy, broken-down rhubarb instead of tender pieces in a thick sauce.

Since sugar-free sweeteners don’t thicken like regular sugar does, your jam will look thinner while hot but will set up as it cools, so resist the urge to keep cooking it until it looks thick in the pan.

Finally, taste your jam before adding the food coloring, as some sweeteners can have a bitter aftertaste that intensifies during cooking – you might need to adjust with a bit more sweetener or lemon juice to balance the flavors.

What to Serve With Rhubarb Jam?

This sugar-free rhubarb jam is perfect spread on warm buttered toast or English muffins for breakfast. I love swirling it into plain Greek yogurt or oatmeal to add a tangy sweetness without the extra sugar. It also makes a great filling for thumbprint cookies or layered between vanilla cake layers. If you’re feeling fancy, try spreading it on scones with a dollop of whipped cream, or use it as a topping for pancakes and waffles on lazy weekend mornings.

Storage Instructions

Store: Keep your rhubarb jam in a clean jar or airtight container in the fridge for up to 2 weeks. Since this is sugar-free, it won’t last quite as long as traditional jam, so make sure to use a clean spoon each time to help it stay fresh longer.

Freeze: This jam freezes really well if you want to make a bigger batch. Just portion it into small freezer-safe containers or ice cube trays, leaving a bit of space at the top for expansion. It’ll keep in the freezer for up to 3 months.

Thaw: When you’re ready to use frozen jam, just move it to the fridge the night before and let it thaw slowly. Give it a good stir once it’s thawed, as it might separate a bit. You can also thaw smaller portions at room temperature for about an hour.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 50-100
• Protein: 1-2 g
• Fat: 0-1 g
• Carbohydrates: 15-25 g

Ingredients

• 14 oz rhubarb (cut into 1/2-inch pieces)
• 3/4 cup sweetener (I prefer Lakanto Monkfruit for a zero-aftertaste finish)
• 1.5 tsp lemon juice (freshly squeezed for better pectin activation)
• 1 drop red dye
• Pinch of salt

Step 1: Prepare and Macerate the Rhubarb

• 14 oz rhubarb, cut into 1/2-inch pieces
• 3/4 cup sweetener

Cut the rhubarb into 1/2-inch pieces and place in a bowl with the sweetener.

Stir to combine, then cover and let sit overnight at room temperature.

This maceration step is crucial—it draws out the rhubarb’s natural juices and allows the sweetener to dissolve, creating a syrup base that will help the jam set properly.

I find this overnight step essential for achieving the right consistency without needing additional pectin.

Step 2: Cook the Jam Base

• Macerated rhubarb mixture from Step 1
• 1.5 tsp lemon juice, freshly squeezed
• Pinch of salt

Pour the rhubarb mixture (fruit, accumulated liquid, and sweetener) into a heavy-bottomed saucepan or jam pan.

Add the freshly squeezed lemon juice and a pinch of salt.

The lemon juice activates pectin naturally present in rhubarb, helping the jam achieve the proper gel, while the salt enhances the fruit flavor without making it taste salty.

Bring to a rolling boil over medium-high heat, stirring occasionally to ensure even cooking.

Step 3: Simmer Until Jam Sets

• Cooking rhubarb mixture from Step 2

Once boiling, cover the pan and reduce heat to medium-low.

Simmer gently for 15 minutes, stirring occasionally.

The rhubarb will break down and the liquid will reduce and thicken.

I like to check the consistency by placing a small spoonful on a chilled plate—if it wrinkles slightly when pushed, it’s ready.

The jam will continue to thicken as it cools, so don’t over-cook it.

Step 4: Add Color and Cool

• 1 drop red dye
• Cooked jam from Step 3

Remove from heat and add one drop of red food dye if desired, stirring well to distribute the color evenly throughout the jam.

Pour the jam into sterilized jars and let cool to room temperature on the counter.

As it cools, it will continue to set and reach its final gel consistency.

Keto Sugar Free Rhubarb Jam

Delicious Keto Sugar Free Rhubarb Jam recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 10 minutes mins

Cook Time 25 minutes mins

Total Time 35 minutes mins

Servings: 2 cups of jam

Calories: 75

Ingredients Method

Ingredients

  

• 14 oz rhubarb (cut into 1/2-inch pieces)
• 3/4 cup sweetener (I prefer Lakanto Monkfruit for a zero-aftertaste finish)
• 1.5 tsp lemon juice (freshly squeezed for better pectin activation)
• 1 drop red dye
• Pinch of salt

Method

 

1. Cut the rhubarb into 1/2-inch pieces and place in a bowl with the sweetener. Stir to combine, then cover and let sit overnight at room temperature. This maceration step is crucial—it draws out the rhubarb's natural juices and allows the sweetener to dissolve, creating a syrup base that will help the jam set properly. I find this overnight step essential for achieving the right consistency without needing additional pectin.
2. Pour the rhubarb mixture (fruit, accumulated liquid, and sweetener) into a heavy-bottomed saucepan or jam pan. Add the freshly squeezed lemon juice and a pinch of salt. The lemon juice activates pectin naturally present in rhubarb, helping the jam achieve the proper gel, while the salt enhances the fruit flavor without making it taste salty. Bring to a rolling boil over medium-high heat, stirring occasionally to ensure even cooking.
3. Once boiling, cover the pan and reduce heat to medium-low. Simmer gently for 15 minutes, stirring occasionally. The rhubarb will break down and the liquid will reduce and thicken. I like to check the consistency by placing a small spoonful on a chilled plate—if it wrinkles slightly when pushed, it's ready. The jam will continue to thicken as it cools, so don't over-cook it.
4. Remove from heat and add one drop of red food dye if desired, stirring well to distribute the color evenly throughout the jam. Pour the jam into sterilized jars and let cool to room temperature on the counter. As it cools, it will continue to set and reach its final gel consistency.