jars of blueberry jam

Keto Blueberry Jam (canning, preserving)

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Yes, you can preserve homemade Keto Blueberry Jam! It’s healthy, low-carb, and simply delicious!

We love going berry picking in the summer. My kids usually eat more than they collect, but that’s to be expected, right? We eat our berries fresh on our pancakes (hello Carnivore Pancakes), freeze them, or I make jars of jam and preserve them. The jam tastes fresh even after one year and tastes amazing on my Keto Rustic Bread.

Can jam be low-carb?

Traditional jam is made with tons of sugar and if you buy jam from the grocery store, you may even encounter brands that use high-fructose corn syrup! That, of course, won’t work for a low-carb lifestyle.

My Keto Blueberry Jam on the other hand is made without any addition of sugar. Instead, we use a low-carb sweetener – granular erythritol, which looks and tastes very similar to sugar. Now the jam will not be sugar-free because blueberries have fruit sugar. However, because blueberries are lower in fruit sugar than other fruits, you can enjoy this jam guilt-free on your grain-free bread, keto waffles, or even low-carb ice cream!

One tablespoon of this jam only has 1 gram of sugar.

What ingredients do I need?

ingredients for Keto Blueberry Jam

The ingredient list for this jam is pretty short and straightforward: blueberries, granular erythritol, bottled lemon juice, low-sugar pectin, and water.

Blueberries. You will need 4 pounds of blueberries. Both fresh or frozen blueberries will work.

Erythritol. Granular erythritol works great for this jam. It won’t recrystallize because of the high water content and heat we use to make the jam. If you want to substitute with another sweeter, you will need to use the same amount of sweetener, which is 1 cup. That’s means you can’t replace the erythritol with a few drops of stevia. You also can’t leave out the sweetener for this specific recipe, as volume matters for the pectin to work.

Lemon juice. Always use bottled lemon juice for jam.

Pectin. To make this low-carb jam, you need to use low-sugar needed pectin. I have only tried the low-sugar needed pectin by Ball to make my jam, so I recommend you use the same. If you want to use a different brand of low-sugar pectin, feel free to do so, you may just need to change the proportions of the ingredients (according the product’s description).

Unlike regular pectin, low-sugar needed (or no sugar) pectin is activated without the addition of sugar. You may notice that commercial pectin is made with dextrose (a type of sugar). The amount of this is so low though, that it only has a small effect on the sugar content of the jam.

What canning tools do I need?

canning tools

As with everything, I try to keep my number of kitchen accessories low. To can jam, I only need 8-oz canning jars with fitting lids and bands, a large canner with rack, ladle, jar funnel, and jar lifter. I also use a potato masher to mash my blueberries and a large wooden spoon for stirring.

I re-use my canning jars (unless I see a crack) and bands, but always use new lids (old lids may not seal).

Canning step-by-step!

Prepare your jars. Wash your canning jars and lids in soapy, hot water (no need to sterilize, as we will process the jars for 10 minutes). Keep jars warm until ready to be filled with jam (I just keep them submerged in warm water).

Heat blueberries. Place blueberries in large pot, heat over medium heat, and mash with potato masher until you’ve mashed most of the blueberries. It will look like a thick sauce.

Add ingredients and first boil. Add lemon juice, water, and pectin, one tablespoon at a time. Increase heat to high, and while (slowly) constantly stirring bring mixture to a rolling boil (that can’t be stirred down). Watch out that mixture doesn’t boil over.

Add erythritol. Add sweetener and bring to another rolling boil while constantly stirring. Keep the hard boil going for 1 minutes. Then turn off heat.

Remove foam. You may see some foam on top. Skim foam with a spoon. I love eating the foam and simply put it in the fridge. If you don’t like the foam, you can simply add a bit of butter (1/4 tsp) after you add the pectin. This will prevent the foam.

Fill up jars. Fill hot jam into warm jars, one at a time. Place jar funnel into jar and with a ladle pour the jam in. Leave a headspace of 1/4 inch. Wipe the rim with a moist paper towel.

Closing jar. Place lid on jar. Then screw on band, but just finger-tight. This will allow steam to escape.

Processing. Place jars into canner (with the rack sitting at the bottom). Fill canner with enough water to cover jars with 2 inches of water. Bring to a gentle boil and boil for 10 minutes.

Increase processing time for high altitudes: +5 minutes for 1001-3000 feet, +10 minutes for 3001-6000 feet, +15 minutes for 6001-8000 feet, and +20 minutes for 8001-10,000 feet.

Cooling jar. With a jar lifter, remove jars from canner (repeat processing with uncanned jars if you need to process in batches, making sure to add more water to canner). Let jars cool down completely (about 12 hours). During this time, don’t touch lids. You will hear popping sounds as the lids seal.

Check seal and dry bands. After the 12 hours, check the seal by pressing down on the lid center. The lid should not flex up or down. If it does, it didnt’ seal correctly. In that case, you can either try processing again with a new lid or place that jar in fridge an eat within 2 weeks.

Unscrew bands from jars (leave the lids on) and dry bands with paper towel in case they are wet (this will prevent them from rusting). Screw the band back on and store in cool, dark place for about 1 year.

Tips for making Keto Blueberry Jam!

fresh blueberry jam

Sanitizing. There is no need to pre-sanitize the jars or lids. That’s because our processing time is 10 minutes, which is enough to sterilize the jars.

Stirring. Always stir jam slowly, as it’s super hot. Use a large wooden spoon for stirring.

Jars. For this recipe you need to use 8-oz jars or smaller. Make sure to use canning jars, as these jars can handle the heat.

Leftovers. This recipe should make about 9 8-oz jars. If after filling your jars with jam, you end up with a jar that’s only 1/2 full, don’t process them. Too much headspace between the jam and rim can prevent proper sealing. Simply place that leftover jam in the fridge and eat it within two weeks.

Double batches. While you can certainly divide this recipe in half if you only have 2 pounds of blueberries, you can’t increase it. A jam batch that makes 10 or more 8-oz jars may not set right.

Storage. If stored in a dark, cool place, the jam should be good for at least one year or longer. We are still eating jam that’s 2 years old without any problems. Aways check the seal before opening a jar and check if the top has any mold. Discard jam with mold.

Once you open a jar, place it in the fridge and eat it within two weeks.

Preserve your summer fruit!

fresh blueberry jam

ENJOY THE JAM WITH THIS

Keto Rustic Bread
Keto Rustic Bread
Keto Yogurt Waffles served with whipped cream and macerated strawberries.
Keto Waffles
Serving of EASY Keto Vanilla Ice Cream with macerated strawberries.
Easy Vanilla Ice Cream
jars of blueberry jam

Keto Blueberry Jam (canning, preserving)

Yes, you can preserve homemade Keto Blueberry Jam! It's healthy, low-carb, and simply delicious!
5 from 3 votes
Prep Time 5 minutes
Cook Time 10 minutes
Processing 10 minutes
Total Time 25 minutes
Course Breakfast, Dessert
Cuisine American, German
Servings 9 jars
Calories 9 kcal

Ingredients
  

Instructions
 

Making Jam

  • Wash your canning jars and lids in soapy, hot water (no need to sterilize, as we will process the jars for 10 minutes). Keep jars warm until ready to be filled with jam (I just keep them submerged in warm water).
  • Place blueberries in large pot, heat over medium heat, and mash with potato masher until you've mashed most of the blueberries. It will look like a thick sauce.
  • Stir in lemon juice and water. Gradually stir in pectin (1 tbsp at a time). Increase heat to high, and while (slowly) constantly stirring bring mixture to a rolling boil (that can't be stirred down). Watch out that mixture doesn't boil over.
  • Add granular erythritol and bring to another rolling boil while constantly stirring. Keep the hard boil going for 1 minutes. Then turn off heat.
  • You may see some foam on top. Skim foam with a spoon. I love eating the foam and simply put it in the fridge. If you don't like the foam, you can simply add a bit of butter (1/4 tsp) after you add the pectin. This will prevent the foam.

Processing jam

  • Fill hot jam into warm jars, one at a time. Place jar funnel into jar and with a ladle pour the jam in. Leave a headspace of 1/4 inch. Wipe the rim with a moist paper towel.
  • Place lid on jar. Then screw on band, but just finger-tight. This will allow steam to escape. Place jars into canner (with the rack sitting at the bottom). Fill canner with enough water to cover jars with 2 inches of water. Bring to a gentle boil and boil for 10 minutes. (Adjust for altitude, see notes.)
  • With a jar lifter, remove jars from canner (repeat processing with uncanned jars, making sure to add more water to canner). Let jars cool down completely (about 12 hours). During this time, don't touch lids. You will hear popping sounds as the lids seal.
  • After the 12 hours, check the seal by pressing down on the lid center. The lid should not flex up or down. If it does, it didnt' seal correctly. In that case, you can either try processing again with a new lid or place that jar in fridge an eat within 2 weeks.
  • Unscrew bands from jars (leave the lids on) and dry bands with paper towel in case they are wet (this will prevent them from rusting). Screw the band back on and store in cool, dark place for about 1 year.

Video

Notes

Increase processing time for high altitudes: +5 minutes for 1001-3000 feet, +10 minutes for 3001-6000 feet, +15 minutes for 6001-8000 feet, and +20 minutes for 8001-10,000 feet.
Sanitizing. There is no need to pre-sanitize the jars or lids. That’s because our processing time is 10 minutes, which is enough to sterilize the jars.
Jars. For this recipe you need to use 8-oz jars or smaller. Make sure to use canning jars, as these jars can handle the heat.
Leftovers. This recipe should make about 9 8-oz jars. If after filling your jars with jam, you end up with a jar that’s only 1/2 full, don’t process them. Too much headspace between the jam and rim can prevent proper sealing. Simply place that leftover jam in the fridge and eat it within two weeks.

Nutrition

Serving: 1tbspCalories: 9kcalCarbohydrates: 2gProtein: 0.1gFat: 0.04gFiber: 0.3gSugar: 1g
Keyword Keto breakfast, low-carb breakfast
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