How to Preserve Blueberries without Sugar

Blueberries are one of the healthiest fruits, and I think they are also one of the best tasting ones. In this post I’ll be sharing my favourite ways to preserve blueberries to enjoy all through the year.

Why preserve blueberries without sugar?

Blueberries have an intense taste of their own, and it’s nice to highlight that taste rather than making things overly sweet. For water bath canning purposes, they also have enough acidity of their own to preserve just as a sauce or in water.

For health reasons, I don’t eat refined sugars. Whole unrefined cane sugar and coconut sugar have strong tastes that overwhelm the flavour of the fruit, and honey can be expensive, so I really enjoy the preservation methods I discuss in this article, because all of them are sugar-free, and most of them don’t use any honey at all.

How to dehydrate blueberries

Dried blueberries are so delicious! You can eat them by the handful, add them to trail mixes, or use them in place of raisins in recipes. One of my favourite ways to use them is in oat slice (baked oatmeal), feel free to add them to muffins, scones, cookies, granola, muesli, and more.

Dehydrator method (solar or electric)

To dehydrate blueberries, simply spread them out on dehydrator trays and dry them in an electric or solar dehydrator until there are no signs of liquid when you break one in half and squeeze it. You may need to taste-test a few along the way just to make sure!

Oven method

To dehydrate blueberries in the oven, simply spread them out on a cookie sheet, and bake in a very very low oven (the lowest it will go) with the door kept slightly ajar, until there are no signs of liquid when squeezed. I use the bottom oven of my wood cookstove.

Fruit leather (fruit roll-up) method

Run blueberries through a food processor or blender and spread out thinly on non-toxic baking paper. Dehydrate in the oven or in a dehydrator until leathery, and there is no sign of liquid when you tear a bit off and squeeze it. You can also add applesauce to the blueberry mixture.

How to can blueberries without sugar

All the canning instructions I’ll share here are for altitudes below 1000 feet (300m). If you live at a higher altitude than this, you’ll need to adjust your timing. Practical Self Reliance has a table for adjusting canning for altitude on the article about how to can blueberries.

Blueberry sauce

I make a lot of this blueberry sauce (or blueberry compote) to serve with porridge, or use for blueberry crumble and pies. To make sugar-free blueberry sauce for canning, simply put your blueberries in a pot with no added liquid, heat gently while smashing them up with a wooden spoon. Heat until they are bubbling in plenty of their own liquid. Put into canning jars, leaving 1/4″ (1/2cm) headspace, seal in the usual way, and can in a boiling water bath canner for 20 minutes for pints or 25 minutes for quarts.

Canned blueberries in water

You can also can blueberries in water. Simply raw pack your blueberries into a canning jar, leaving 1/2″ (1cm) headspace, top with water until just above the level of the berries, seal in the usual way, and can in a boiling water bath canner for 15 minutes for pints or 20 minutes for quarts. If you do this, the flavour of the berries will get a bit diluted, so I prefer to can in honey syrup, below, or make blueberry sauce, above.

How to can blueberries in honey syrup

Blueberries in honey syrup are one of my favourite fruits to use in muffins and cakes. Not only do you get delicious blueberries, preserved and ready to go in all your favourite recipes, you also end up with a blueberry syrup that you can use as a sauce for cakes, pancakes, or ice cream, or to add to a second ferment brew of kombucha or kefir, or as a sweet drink on its own.

To preserve blueberries in honey syrup, first make an extra light honey syrup by combining 1 part honey by weight with 4 parts water by weight. This works out to be around 340g (1 cup) honey to 1360g (5 1/2 cups) water. Bring the syrup to the boil, and keep it hot while you prepare the berries.

The amount of syrup that you’ll need will depend on how many jars you are making, the size of your berries, and whether you are hot packing or raw packing. If you end up with extra syrup, you can always can it on its own or freeze it, and then use it to can other fruit such as peaches, plums, cherries, and apricots.

Raw pack method

Put your blueberries in canning jars, leaving 1/2″ (1cm) headspace. Top with the honey syrup, seal in the usual way, and water bath can for 15 minutes for pints and 20 minutes for quarts.

Hot pack method

With hot packing, you can fit more berries into each jar, but some varieties of blueberries can get too soft with this method, so you may want to test a small batch out, just to be sure. My favourite type of blueberry is blue crop, and this handles hot pack canning without problems.

To hot pack blueberries in honey syrup, bring the syrup to the boil, stir through the berries briefly, just to coat them in the hot syrup, then remove from the heat. Pack the hot blueberries and syrup into jars, seal in the usual way, and water bath can for 15 minutes for pints and 20 minutes for quarts.

How to freeze blueberries

Freezing blueberries is one of the simplest ways to preserve them, if you have the freezer space for them.

To freeze blueberries, do not wash them, but simply put them in a bag or container and freeze them. If they are unwashed, they will freeze as loose berries, and then it is really simply to just shake some out of the bag the next time you want to make muffins or a smoothie.

If your blueberries are a bit wet from washing or rainfall, or if you’re extra worried about them sticking together, you can also freeze them on a cookie sheet, and then when frozen, transfer to a bag or container for storage.

Blueberry jam

To make blueberry jam without sugar, simply follow my method for making jam with honey instead of sugar.