More and more people are looking for a sugar-free blueberry jam for breakfast, to have with yogurt or to use in baking. You can make it at home with very few ingredients in under half an hour. There is one thing to be clear about from the start, though. Without sugar, the jam does not keep like a traditional jam, so you need to treat it as a fresh product. At Finca El Ribeiro, in San Martín de Luiña, we grow blueberries and make our own artisan jam, so here is the homemade recipe, how to store it safely and why ours contains sugar.
Why sugar-free jam keeps differently
In a classic jam, sugar does two jobs. It gives sweetness and helps the jam set, but it also acts as a preservative, because it reduces the water available to microorganisms. Take it out and the jam is closer to a fruit compote. It is delicious, but it does not last long.
That is why homemade sugar-free blueberry jam is kept in the fridge and eaten within a few days, or frozen in portions. It is not a pantry preserve.
Ingredients for sugar-free blueberry jam
For one jar of about 300 ml.
- Blueberries. 400 g, fresh or frozen.
- Lemon juice. One tablespoon, which adds acidity and helps it set.
- Chia seeds. One or two tablespoons, to give body without sugar.
- Optional sweetness. A small grated apple or a couple of chopped dates, for anyone who wants it sweeter.
- Cinnamon or vanilla. Optional, for aroma.
Ripe blueberries already have their own sweetness. If they are very tart, the grated apple softens the result without adding any sugar.
Blueberry jam recipe step by step
- Prepare the fruit. Wash the blueberries and drain them. If they are frozen, use them straight from the freezer.
- Cook. Put them in a saucepan with the lemon juice and the apple or dates if you are using them. Cook over medium heat until they release their juice, about 5 minutes.
- Mash. Crush some of the fruit with a fork or a potato masher. Leave some blueberries whole for texture.
- Reduce. Cook over low heat for 10 to 15 minutes, stirring, until the juice looks thicker.
- Thicken. Take it off the heat, add the chia, stir and let it rest for 10 minutes. The chia absorbs liquid and the jam gains body as it cools.
- Jar it. Transfer to a clean jar and let it cool before closing it and putting it in the fridge.
To check it is ready, put a drop on a cold plate. If it stays in place and does not run, it is done. Remember that it thickens more as it cools.
How to sterilize the jars
Even if you are going to keep it in the fridge, it is best for the jar to be clean and sterilized so that it lasts as long as possible.
- Wash the jar and lid with hot soapy water and rinse them well.
- Place them in a pot, cover them with water and boil them for 10 minutes.
- Take them out with tongs and let them drain upside down on a clean cloth.
- Fill them while they are still hot, taking care not to touch the inside.
Sterilizing the jar does not turn this jam into a long-life preserve. It only reduces the risk of initial contamination.
How long it lasts and how to store it
- In the fridge. Between 7 and 10 days in a closed jar. Always use a clean spoon to serve it.
- In the freezer. Up to about 3 months, divided into small portions or in an ice cube tray. Thaw it in the fridge.
- Warning signs. Mold, bubbles, a fermented or rancid smell. If you see any of them, throw it away without tasting it.
If you want a preserve that lasts for months in the pantry, you need a recipe with sugar and a proper sterilization process for the filled jars, which is a different technique.
An honest note about our jam
Our blueberry jam is artisan and made with organic cane sugar. It is not a sugar-free jam and we do not want to present it as one. The sugar in the recipe is part of what makes it stable, tasty and easy to store. If you prefer a jar that lasts in the pantry and can be opened whenever you like, it is a good option. You can see it in the jams and juice section.
If your aim is to watch the sugar in your diet, the homemade recipe in this article gives you more control. For any personal question about nutrition, consult a health professional.
Variations to change the flavor
- With ginger. A little grated ginger adds a fresh, spicy touch.
- With orange. A little zest and the juice instead of the lemon.
- With other fruits. Mix the blueberries with raspberries or ripe pear.
With any variation, keep the same rule. Store it in the fridge and eat it within a few days. Make small batches and repeat the recipe when it runs out, so you always have it fresh.
Ideas for using it
- On plain yogurt or cottage cheese.
- On toast with fresh cheese.
- As a filling for crepes or pancakes.
- With oatmeal porridge in the morning.
If you are looking for more sweet ideas, take a look at the recipes with our products and the guide to the properties of blueberries.
Frequently asked questions
Can you make blueberry jam without sugar?
Yes. You make it by cooking the blueberries with lemon juice and thickening with chia. The result is closer to a compote and it keeps in the fridge.
How long does sugar-free jam last?
Between 7 and 10 days in the fridge in a closed, clean jar. If you want it to last longer, freeze it in portions for up to about 3 months.
Do the jars need to be sterilized?
It is recommended. Boil the jar and lid for 10 minutes and fill them while still hot. It helps prevent contamination, although it does not turn the jam into a long-life preserve.
Can I use frozen blueberries?
Yes, they work just as well. Put them straight into the saucepan and add a few minutes of cooking so they release their juice.
Does the farm’s jam contain sugar?
Yes, it is made with organic cane sugar. It is an artisan jam, not a sugar-free jam.
Try our blueberry jam
If you would rather buy it ready made, our artisan blueberry jam and the rest of the farm’s products are available in the shop. And if you feel like making the homemade version, you can get our fresh blueberries in season.