Blueberry lemon thyme jam, a refreshing spread for any season. It’s almost the end of the season for blueberries, so it’s a perfect time to “prolong” summer by making some jam to enjoy it in the coming foggy autumn and cold winter.
Making jam is very satisfying especially if you are using your own fruit from the garden. There is always something gratifying to be able to grow, nurture, and finally pick the fruit. There are around 35 blueberry bushes in our garden so generally, if the season is good, there are plenty of berries rolling around for jam and all kinds of other goodies. We especially love them on granola and pancakes.
About the berries
Blueberry season can stretch almost all summer long and the best thing about them is that they don’t ripen all at once. So you get to nibble on the little berries all summer long.
For the jam, make sure to get nice plump berries, which have an icy indigo color. If there are any pink spots around the berry stalk it means they are not fully ripe. When you taste them they should be nice and sweet with a very low acidic flavor. If, on the other hand, they are not plump but starting to soften, they are overripe and not very good for jam making.
I always add lemon in some form, juice or the zest, to my jams. So this time I thought why not add even more lemony aroma but not in the form of more lemons. Meet the lemon thyme. The lemon thyme adds another dimension to this jam. It is very subtle but it is noticeable in the final flavor of the blueberries providing another layer with that sweet lemony aroma. It just works.
To get even more flavor from the thyme, I love to crush the thyme leaves with the sugar in the mortar and pestle to release all the oils from the thyme.
How to Make the Blueberry Lemon Thyme Jam
Making jams is not overly complicated, but it can be time consuming if you are making a large batch. It generally involves 3 steps:
- Cooking the fruit
- Sterilizing the jars – while the fruit is cooking
- Preserving the jam – kind of just leave it to do its thing
Note that if you making only a small batch of jam and are planning to use it within a couple of weeks while storing it in the fridge, then you don’t need to preserve the jam. But don’t forget to store it in the fridge, otherwise, it will go bad.
This recipe is intentionally made for a smaller batch solely for the purpose of not needing to preserve it. Just scale it up if you wish to make larger quantities and do step 3, preserving the jam.
The time it takes to cook the fruit depends on the fruit itself given its stage of ripeness. The best way to test the jam is to smear a tablespoon of cooked fruit on a frozen plate, leave for half a minute, and try it. The jam, if properly cooked, should form a slight wave structure when scraped with a spoon, should be glossy, not very runny, but also not hard that it leaves a clear spoon mark.
Important things
One of the key things is to always use ripe fruit, but not falling apart ripe. This will reduce the sugar you will need to add and it just tastes way better. I don’t like the jam to be too sweet so that the fruit flavor is overpowered with the sugar and you can barely taste the fruit.
The second key thing is to properly sterilize the jars. This reduces the potential bacteria and the jam will last longer.
If you prefer you can always freeze the fruit and make the jam whenever it suits you. This way you can make smaller quantities so that the whole kitchen does not look like a production line.
Blueberries don’t contain enough acid, and we need the acid to bond the pectin, so we add some lemon juice to fix the problem. The lemon juice will help the jam to form pectin bonds and set nicely.
Other Jam Recipes
Blueberry lemon thyme jam
Equipment & Tools
- Mortar and pestle
- Canning utensils: jar lifter, jar mouth funnel
- Canning rack
- 3x290ml canning jars
INGREDIENTS
- 10 g lemon thyme (leaves only, approx. one bunch)
- 120 g unrefined sugar
- 600 g blueberries
- 1 lemon (juice)
- ½ tsp vanilla paste (Nielsen-Massey)
INSTRUCTIONS
General prep
- Take a dessert plate and put it in a freezer.
- Wash the jars and the lids. Drain from water.
- Place the jars and the lids, upside down in the oven. Turn the oven on at 100°C.
- Once the oven reaches the temperature, turn it off but leave the jars inside until the jam is ready.
Make the jam
- Wash the lemon thyme and pick the leaves and add to the mortar and pestle.
- Add 2 tbsp of sugar and mash with the lemon thyme leaves until there are no more leaves and it has more of a paste structure. If there are any small branch-like elements from the thyme remove them.
- Wash the blueberries and drain them. To get all the excess water out place them on a clean kitchen towel and very gently pat them dry.
- In the cooking pot add all the blueberries, remaining sugar, lemon juice, vanilla paste, and the crushed lemon thyme leaves from the mortar and pestle.
- Bring to a boil, lower the heat to medium and simmer for about 15 minutes. Stir the mixture constantly.
- If there is any foam forming on top use a spoon to remove it.
Fill the sterilized jars
- Using jar lifter or baking gloves carefully remove a jar from the oven. They will be quite hot, so be careful not to burn yourself.
- Using a larger spoon, carefully scoop some jam into the jar. Use a jar funnel if you have one. If not, try not to drop any jam on the jar rim. Fill the jar by leaving about 1 cm / 0.2in space from the top.
- Check that the rim of the jar is clean (no jam on it), and if not, take a clean kitchen towel and wipe it clean and dry.
- Place the lid on top, close tightly. When you put the lid on, it should not touch the jam inside. Set aside.
- Repeat with other jars and the remaining jam.
Preserving the jam
- Using a large stainless steel pot place a canning rack on the bottom. See note if you don't have a canning rack.
- Carefully place the filled jars on the canning rack.
- Add hot boiling water to the pot to cover almost the full height of the jar.
- Turn the heat on medium to achieve a very slow simmer. Simmer for at least 10 minutes.
- Turn the heat off and let the jars cool in the pot.
- Once cooled, wipe the water marks from the jar and store them in a cool place.
NOTES
- If the jar lids have a rubber band which is separate from the lid, don’t put them in the oven along with the jars and lids.
- Due to the low sugar content of the jam use smaller jars for storing, or a size where the jam will be consumed in several weeks after opening. This ensures that you consume the jam and it does not go bad.
- Before closing the lids fully, always check that you placed the lid correctly as any air circulation will not allow for the jam to be preserved correctly. This is especially important with the jar that has a rubber band separately from the lid (e.g. Weck jars).
- The jam is properly preserved if the top of the lid is convex or indented inward and pressing on it does nothing. If it is concave and when you press it, it indents inwards then you should reseal the jar and repeat the preserving process since the jar did not seal airtight. Or just consume this jar first.
- If you don’t have a canning rack for the pot, use kitchen cloth. It is important for the jars not to be directly on the heat source. Just fold the kitchen cloth so that it covers the bottom of the pot and it is folded at least 4 times. If it is too small for 4 folds then use two cloths. Make sure that when you place the jars they are leveled and not tilted to the side.
- Once you start to consume the jam and the jar is not sealed airtight anymore, it is best to keep it in the fridge.
