raspberry with blackberry jam - mason jar

Mostly raspberry (with a little blackberry) jam

Batch of raspberry with blackberry jam in jars with lids
finished batch of jam.

I made 4 batches of jam this year. This is the first time I have made jam by myself – I used to help my mom make it when I was younger. It turned out to be easier than I thought, which is probably why I ended up making it so many times. The first three batches were straight blackberry, as we have lots of places to pick very close to my house.

We were given some raspberries from a customer’s garden so I decided to try a raspberry jam. I didn’t have quite enough so I added some leftover blackberries. From what I read, it is OK to substitute fruit for a jam recipe as long as you substitute similar fruit, for example blackberry or salmonberry for raspberry; pear for apple; blackcurrant for cranberry and so on.

For all my jams I used Certo pectin. I followed their instructions for cooked jam. Sterilizing is important when making jam, so you can store for a long time without fear of bacteria growing. Certo recommends sterilizing jars in the oven at 225 degrees F, for 10 minutes, and keeping warm until filling time. Lids should be kept in a pot of boiling water until ready to use.

Everything I read said to make sure you follow recipes for jam closely, and do not try to double recipes, or alter ratios of fruit and sugar. The fear is that the jam may not set properly. I found I was able to add one to one extra fruit to get a bit more out of a batch, and my jam still firmed up great. The only time it didn’t firm up properly was when I left on the stove for longer than recommended, which I found out after can ruin some of the properties of the pectin that help firm up the jam. Here is the recipe I used, which made about 9 cups of jam.


6-7 cups prepared berries (I mashed them through a sieve with a pestle so to remove some seeds, then added back about 3/4 of a cup of the fruit pulp). Certo calls for 6 cups, but I used about 7 including the fruit pulp.

4.5 cups granulated (white) sugar

1 box CERTO Light Pectin Crystals (these are the ones that say “Use 33% less sugar” – I also used the regular pectin for other batches of jam, they required more sugar though. Each pectin box comes with its own recipes).

Zest of 1 lemon (this was my own addition and added a wonderful flavour)


1. In a large saucepan stir together berries, lemon zest, and pectin mixed with 1/4 cup of sugar.

2. Bring to a boil over high heat.

3. Add the rest of the sugar and continue to stir.

4. Return to a hard boil (where bubbles don’t go away even with stirring) for 1 minute.

5. Remove from heat. Stir for 5 minutes to prevent floating fruit. Pour into warm sterilized jars, leaving 1/4 inch of space below the rim. Cover with lids and screw rings on tightly. Leave to set for a few hours at least. After 10 minutes or so you will start to hear a popping sound as the lids seal.

If you have extra, you can put some in any glass container you have and once set, put in fridge and eat within 3 weeks. You will see in the photos below of “just filled jars” that there is one glass mug at the bottom right that is half full – this one doesn’t have a lid and is getting eaten this week!

Setting up to make raspberry with blackberry jam
getting started
crushing blackberries through a sieve with a pestle
crushing berries with a pestle
raspberry with blackberry jam being made with lemon zest
adding pectin and lemon zest
raspberry with blackberry jam - stirring the pot
stirring the pot
raspberry with blackberry jam - just filled jars
just filled jars
raspberry with blackberry jam – just filled jars
just filled jars
raspberry with blackberry jam - mason jar
jam in mason jar
raspberry with blackberry jam - mason jar
jam in mason jar






3 responses to “Mostly raspberry (with a little blackberry) jam”

  1. leon Avatar

    I want a jar. I love raspberry jam.

    1. aldea Avatar

      You got it Leon!

  2. Laura Avatar


    I am creating a fictional website for a uni project and was wondering if I could use some of your images posted in this jam article. All images will be attributed to you and the site will only be live until the end of the semester (end of November).

    Many Thanks

    Laura Richards
    Curtin University, Australia

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