I love blueberry jam but most of those you can find in the stores have some kind of chemical ingredients to stablize their products. So I have decided to make my own. It’s super easy anyway!!
One day when I was doing grocery shopping, there was big discount on blueberries. I just can’t help myself for not buying a few boxes. But then obviously I could not finish them all before some of them may turn bad. The best ways to deal with leftover blueberries is to freeze them for later use, or to make blueberry jam. A jar of jam can be kept in fridge for more than a month (or even longer if you keep it airtight with the vacuum seal in fridge). Below are the steps of how to make and store them.
Step 1 – Sterilize your jars
Boil your glass jars and lids in a large bowl of water for 10 mins. Make sure the water level covers the jars. Try to use jars without any paper labels (I could only find two this time and had to use the third one with label).
Use a pair of tongs to remove them from water (pour out all the water inside jars), set aside and let them dry.
Step 2 – Prepare your blueberries
Slightly wash and drain 500g of blueberries. You can make more or less as you wish. But I would usually make a little more since the effort of making one jar and two jars are the same.
Add 40-60% (of the weight of your berries) of white sugar to your berries. The original recipe calls for 60% sugar but I am trying to cut down a bit on my sugar and therefore have cut it down to 40%, my end product still taste and look great. So for my 500g berries, I would add 300g of sugar.
Mix the sugar and blueberries, use a folk to crush some berries but leave some of them un-crushed as you may want to eat some whole blueberries in your jam.
Note: some recipes also call for 1-2 tablespoon of lemon juice and a bit of cinnamon and pectin (natural thickener). But I think they are totally optional. I have been making my jam without those anyway.
Step 3 – Cook and stir
Use a big bowl to boil your blueberries over medium heat. Keep stirring. You can use higher heat in the beginning when the sugar melts and the mixture comes to boiling. But as you keep boiling it and water evaporates, your mixture will gradually thicken. Then you will need to lower your heat to medium or medium low. Otherwise the bottom may burn and as the bubbles explode, hot juice may splash out. Keep stirring every minute or two. Using a bigger bowl helps to prevent the hot juice from slashing out all over your stove top.
After boiling for 20 mins, the mixture will further thicken. To protect my hand from the hot splashes, I have wrapped a wet cloth around my hand, or you can wear gloves.
Step 4 – Determine when you are done cooking
You will need to keep boiling and stirring for about 30 mins. Depending how high is your heat and how much blueberries you have used, time required may varies. Your goal is to thicken the paste.
However, note that your jam will thicken further after you package it and store inside fridge. Therefore, NO NEED to cook till it’s too thick like the commercial jam. Here is how to test whether your jam is ready: swirl your spatula through your cooking jam, hold it up over the pot, and watch how it falls. If the jam runs right off the spoon and looks thin and runny, it’s not done yet. However, if it forms thick droplets that hang heavily off the bowl of the utensil, but don’t immediately fall off, it is either nearing completion or is done.
Also note as we do not use any chemical additives or pectin, your jam won’t have the jello like texture like the commercial product.
Step 5 – Storage
Ladle hot jam into your jelly jar. Wipe jar rim clean. Place lid on jar and tighten it while your jam is still hot. Let them cool down in room temperature for 12 hours, then store in fridge.
You may notice that your jar lids are a bit concave in the middle due to the vacuum effect created inside the airtight jar as your hot jam cool off.
When you are ready to enjoy this jam and when you open the jar for the first time, you will hear a pop sound of breaking the vacuum airtight seal.
I love peanut butter and jam buns. 😀
You can find more of my cooking recipes here: Cooking recipes
And more baking recipes and tips here: Baking tips and recipes