Blackberry Freezer Jam

My mom has been making freezer jam for as long as I can remember. Every year when the berries start to ripen all I can think is JAM SEASON!! This summer I made a few batches with my mom, which inspired me to share the recipe for blackberry freezer jam.

image of blackberry freezer jam that has set and is ready to be eaten

I think it’s a loose adaptation from the recipe on the Certo box, but what really makes it so delicious is how she makes it.

That’s what separates this homemade jam from store bought jam. The perfect, sun-ripened berries and the love. It’s also why her jam is famous among our friends and family, who beg for a container every summer.

What Is Freezer Jam?

Freezer jam is by far and away the easiest type of jam to make. It doesn’t involve water baths or complicating canning techniques like some recipes do. In fact, most freezer jam recipes don’t require any cooking at all!

And that’s what makes freezer jam taste so incredible. It gives it a wonderfully bright flavor and color. It’s like biting into a perfectly ripe summer blackberry everytime you taste this jam.

To make freezer jam, you just mash down your fruit and mix it with sugar, then stir in some liquid pectin and lemon juice and you’re good to go.

image of blackberry jam that's been poured into mason jars to set

The hardest part is just waiting for it to set. Then it’s into the freezer for a year’s worth (in our case – we make several batches) of homemade, delicious jam.

Blackberry Freezer Jam Troubleshooting

While this jam is incredibly easy to make, it doesn’t mean that things can’t go wrong. The most common problems people encounter are jam with a grainy texture or jam that doesn’t set.

Why Is My Jam Grainy?

Sometimes even if your jam sets, the texture can be a bit off. If you find your freezer jam has a grainy or sandy texture, it means that the sugar didn’t have a chance to fully dissolve.

The easiest way to prevent this from happening is to let the mashed fruit and sugar sit for about 20 minutes before adding in the pectin.

During this 20 minute window, you want to stir the fruit and sugar occasionally to helps the sugar dissolve.

image of blackberry freezer jam being made in a bowl

It’s equally important to vigorously stir the jam for at least three minutes once you’ve added in the pectin and lemon juice. Not only will you get a great arm workout, you’ll help that sugar break down even more.

My mom would have us do this as kids and I always thought my arm was going to pop off by the end. But now I understand why!

I recommend setting a timer to make sure the sugar has enough time to dissolve properly.

Why Didn’t My Jam Set?

The other common issue with freezer jam is that sometimes it doesn’t set. Freezer jam is supposed to have a thick, pudding-like consistency but if it doesn’t set it will be runny and much thinner.

If your jam doesn’t properly set, it’s usually because the ratio of fruit to sugar was off, your pectin was old, or because your sugar didn’t fully dissolve.

We already discussed how to fully dissolve the sugar, so we’ll focus on the fruit to sugar ratio now.

While you might think 4 cups of sugar is a lot, please resist the temptation to use less. You need 2 cups of sugar for every cup of mashed fruit.

It’s imperative that you use the full amount of sugar and that you don’t add in extra fruit if you want your jam to set.

image of blackberry freezer jam

While it is a lot of sugar, I promise it’s less than you’d find in most store-bought jams or jellies. You also have to remember that you’re only eating a few tablespoons at a time, so the amount of sugar isn’t as crazy as it seems.

Substitutions & Swaps

This recipe is pretty straight forward and doesn’t use many ingredients. There are a few substitutions you can make, but you need to be careful! Like I mentioned above, if the ratio of fruit to sugar is changed the jam won’t set properly.

Below are some swaps and substitutions that can be made in this blackberry freezer jam recipe.

  • Blackberries – You can use pretty much any berry that’s in season! The key thing is using fresh, ripe fruit. Bramble berries, raspberries, boysenberries or even marionberries would work wonderfully in this recipe.
  • Granulated Sugar – I do not recommend changing the amount or type of sugar in this recipe.
  • Lemon Juice – Usually I am all about using fresh lemon juice when I’m baking, but my mom uses bottled lemon juice in this recipe. Bottled lemon juice actually works better than fresh lemon juice because the acidity level is controlled and consistently the same. This helps ensures the pectin will set properly!
  • Liquid Fruit Pectin – I’ve only tried this recipe with Certo, but any liquid fruit pectin should work like Sure Jell or Ball liquid pectin. I find Certo is sold at most grocery stores, or you can order it online.
image of freshly picked blackberries

Tips for Making The Best Blackberry Freezer Jam

  • Use wide-mouthed glass jars for your jam. They’re easier to fill and freeze well! You can also use plastic containers with a rubber seal but I find glass works best.
  • Thoroughly clean and dry your jars before you fill them with jam.
  • The quality of your jam is heavily based on the quality of your berries! It’s best to use freshly picked berries.
  • Make sure your pectin isn’t expired! Check the expiration date on the box to be safe.
  • Use liquid pectin in this recipe not powdered! This recipe will not turn out with powdered pectin.
  • Let the mashed blackberries and sugar sit for at least 20 minutes to allow the sugar to dissolve before adding in the pectin and lemon juice.
  • Use bottled lemon juice instead of fresh lemon juice to ensure the pectin sets properly.
  • Make the jam in a bowl with a spout, or use a funnel or ladel to easily filly your jars. I didn’t and you can see the mess I made!!
  • Don’t fill your containers to the top! Leave at least half an inch, because the jam will expand as it freezes.
  • Set the filled containers somewhere safe and allow them sit at room temperature for 24 hours without being touched. This allows the pectin to work its magic and helps the jam set properly.
  • Label your jars with the date the jam was made. My mom always uses a bit of tape and a sharpie!
  • You can use fresh bramble berries, raspberries, boysenberries, or marionberries in place of the blackberries in this recipe.
image of blackberry freezer jam in a cute mason jar tied with twine

How Long Does Blackberry Freezer Jam Stay Good?

Like the name implies, this jam freezes incredibly well! It can be frozen for up to a year. While it stays good for a long time, I doubt it’ll last that long 😛

When you’re ready to eat a jar of frozen jam, remove it from the freezer and place it in your fridge overnight. It should be thawed and ready to enjoy by the following morning.

You can also put a container straight into the fridge once it’s set. We usually put one in the fridge to enjoy immediately, and the rest in the freezer for later. This jam lasts up to a month in the fridge.

In full disclosure, I’ve eaten a container we found in the back of the freezer that was 2 years old, and it actually still tasted great! But I think it’s better to stay on the safe side and aim to eat this jam within a year of when it’s made.

Let Me Know What You Think!

If you try this recipe for blackberry freezer jam, I’d love to hear what think of it!

Please leave a rating and let me know your thoughts by sharing a comment.

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Yield: 5 cups

Blackberry Freezer Jam

image of blackberry freezer jam

This blackberry freezer jam recipe only takes 30 minutes to make & is packed with flavor. It's so easy to make and delicious you'll never go back to store-bought jam!

Prep Time 30 minutes
Additional Time 12 hours
Total Time 12 hours 30 minutes

Ingredients

Blackberry Freezer Jam

  • 2 cups mashed blackberries - about 3 pints (460 grams)
  • 4 cups granulated sugar (800 grams)
  • 1 pouch Certo liquid Fruit Pectin (3 Fl oz.)
  • 2 Tbsp bottled lemon juice (30 grams)

Instructions

Blackberry Freezer Jam

  1. Begin by washing and drying you containers or jars. Set aside.
  2. Rinse your berries and either dry them gently with a towel or place them in a colander to help drain any excess water.
  3. Mash the blackberries with a potato masher until the mixture looks soupy. This will leave some small bits of the blackberries intact and give the jam a bit of texture.
  4. Use a measuring cup to add exactly 2 cups of mashed blackberries into a separate large bowl.
  5. Add in 4 cups of granulated sugar and stir until the sugar is fully incorporated.
  6. Set a timer for 20 minutes and let the mixture sit, stirring every few minutes to help the sugar dissolve.
  7. Pour 3 Fl oz. or 1 pouch of liquid pectin into the blackberry mixture, being sure to squeeze out every last drop of pectin! Fold the packet down as you go to get all of it out.
  8. Add in 2 Tbsp of bottled lemon juice, then set your timer for 3 minutes and stir the mixture somewhat aggressively. I like to switch arms halfway through so that they don't feel like they're going to fall off.
  9. Pour the mixture into your cleaned and dried jars, leaving at least 1/2 inch at the top of the container. The jam will expand as it freezes, so it's important to leave a little room!
  10. Wipe away any spills, then close the jars with their lids and let them sit for 24 hours at room temperature. Be sure to place them in a safe area where they won't be touched or bumped.
  11. Once the jam has set, place a bit of tape onto each jar and write the date it was made.
  12. Then either freeze or refrigerate the jam! It can be frozen for up to a year or kept in the fridge for up to a month.
  13. To thaw frozen jam, move the container from the freezer to the fridge, then enjoy the following morning once it's thawed.

Notes

Yield

This recipe makes about 5 cups or 40 oz. of freezer jam.

Tips for Making The Best Blackberry Freezer Jam

  • Use wide-mouthed glass jars for your jam. They're easier to fill and freeze well. You can also use plastic containers with a rubber seal but I find glass works best.
  • Mix the jam in a bowl with a spout to make it easier to pour into the jars.
  • Thoroughly clean and dry your glasses before you fill them with jam.
  • The quality of your jam is heavily based on the quality of your berries! It's best to use freshly picked berries if possible.
  • Make sure your pectin isn't expired! Check the expiration date on the box to be safe.
  • Use liquid pectin in this recipe, not powdered! This recipe will not turn out with powdered pectin.
  • Let the mashed blackberries and sugar sit for at least 20 minutes to allow the sugar to dissolve before adding in the pectin.
  • Use bottled lemon juice instead of fresh lemon juice to ensure the pectin sets properly.
  • Make the jam in a bowl with a spout, or use a funnel or ladel to easily filly your jars. I didn't and you can see the mess I made!!
  • Don't fill your containers to the top! Leave at least 1/2 an inch, because the jam will expand as it freezes.
  • Set the filled containers somewhere safe and allow them sit for 24 hours without being touched. This allows the pectin to work its magic and helps the jam set properly.
  • Label your jars with the date the jam was made. Use a bit of masking tape and a sharpie!
  • You can use fresh bramble berries, raspberries, boysenberries, or marionberries in place of the blackberries in this recipe.


Freezing This Freezer Jam

Like the name implies, this jam freezes incredibly well! It can be frozen for up to a year. While it stays good for a long time, I doubt it'll last that long 😛

When you're ready to eat a the frozen jam, remove the container from the freezer and place it in your fridge overnight. It should be ready to enjoy by the following morning.

Nutrition Information

Yield

50

Serving Size

1

Amount Per Serving Calories 70Total Fat 0gSaturated Fat 0gTrans Fat 0gUnsaturated Fat 0gCholesterol 0mgSodium 2mgCarbohydrates 18gFiber 0gSugar 17gProtein 0g

Let me know what you think!