Fresh blackberries, sugar and lemon juice are the ingredients needed to make this delicious jam! No added pectin is needed as wild blackberries are naturally high in pectin.
This seedless blackberry jam is perfect for using on toast or in sandwiches.
This recipe has been updated to reflect additional information and now includes lemon juice. The lemon juice helps the jam set. I have had success with and without the lemon juice, but this can vary depending on your blackberries. I recommend adding the lemon juice to help ensure your jam sets up.
Why make this jam
We have been picking wild blackberries like crazy. Rod told me we have over 8 gallons in the freezer!
Homemade jam is just one way to fully enjoy these amazing berries.
Several years ago I made blackberry jam, but left the seeds in. The jam was delicious, but the seeds seemed really large. I actually thought the jam was hard to eat. Making this jam seedless took an extra step, but was well worth it!
You have several options once you make homemade jam. You can refrigerate and eat it within one month. You can freeze it in smaller portions and pull out when you're ready to eat or you can can it in canning jars and preserve in a hot water bath and keep on your selves in your pantry for up to a year!
I've included instructions for making the jam and for canning the jam!
- Blackberries - fresh or frozen. If using frozen, allow berries to thaw first. Be certain to keep all the juice that is released as the berries thaw.
- Lemon juice
Pectin is a naturally found substance in many berries and fruits. It is also produced commercially to aide in setting jams and jellies. Commercial pectin requires an exact amount of fruit and a high amount of sugar in order for the jam or jelly to set.
Lemon juice and sugar is added to help activate the natural pectin
Blackberries are naturally high in pectin so no added pectin is needed. I always add a few reddish blackberries into the mix because they have even more pectin than the riper black ones.
Because this recipe doesn't use a commercially added pectin, the amount of sugar added is all up to you! I added 4 cups of sugar to 8 cups of strained fruit. Most jam recipes call for equal amounts of sugar to fruit!
Feel free to adjust the sugar to your liking.
Step by step directions
- Mash berries and strain seeds
- Place strained berries, sugar and lemon juice in a pot over medium high heat
- Stir often to avoid scorching
- Heat until jam reaches the gel stage
- If canning, place jam in clean and sterilized jars
- Wipe rim clean
- Add lid and screw cap and process in a hot water bath
How do I know when my jam is done?
Knowing when your jam is set, or done is the hardest part of making jam.
When cooking without commercial pectin you need to rely on a spoon test, a plate test or check the temperature. I like to use at least two methods, and often all three methods when making jam.
The spoon test relies on watching the sheeting or drops as they come off the spoon while it is cooking. When the jam first starts boiling it comes off in drops or thin steams.
When the jam has set, the jam will come off the spoon in more of a sheet. This takes some time to learn what this looks like and even though I've been making jam for years, I always rely on a second method.
Have a small plate chilling in the refrigerator. When you think the jam has set, place a spoonful of hot jam on the cold plate. Wait one minute and draw a line through the center of the jam. If the line holds its shape and doesn't run, the jam is set.
The temperature test is the most reliable. However the exact temperature will vary, depending on your altitude. You will deduct 2° for every thousand feet above sea level. Jam sets at 220° at sea level. I'm at about 2000 feet above sea level and my jam sets between 216° - 218°
I usually watch my jam with a thermometer and when it starts getting close to 215° I begin doing a sheeting test and then the plate test. I don't like to rely on just one method.
Tips for making jam
- Blackberries are very messy and the juice will stain. Wipe up spills and drips quickly and wear something you don't mind if a few stains remain.
- Use a pot that is a least double the size of the ingredients. When you boil jam it will really swell up in the pot.
- Keep a close eye on your jam. You don't want it to burn or boil over. The pictures below show my jam boiling all the way to the very top of a large pot. If this happens, turn down the heat, blow gently on the top of the jam and carefully stir the jam. You don't want it to boil over and lose all that jam and have a burnt sticky mess to clean up.
- Jam will often create foam when boiling. I just ignore the foam. It usually disappears once the jam is set. If you still have foam on top of the jam, you can skim off before canning your jam.
A few tips when canning jam:
- Make certain you always clean and sterilize your jars prior to using.
- Use new canning lids that have been washed.
- Hot water bath your jars according to the size of your jars and always adjust for your elevation.
- Once jars are sealed and cooled for 12 hours, remove rings and wash jars. Replace rings if desired.
- Label and date jars.
If you'd like to freeze excess blackberries, follow these steps for freezing raspberries.
If you make this recipe, I’d love to hear about it! Leave a comment below and snap a picture and tag me on Instagram @beyondthechickencoop
Check out all my Canning Recipes.
Seedless Blackberry Jam
- 12 - 14 cups blackberries (ripe berries and a few unripe berries)
- 4 cups sugar
- 2 tablespoons lemon juice
- Mash and strain seeds from blackberries using a chinois. Measure out 8 cups of strained fruit for jam.12 - 14 cups blackberries
- Put 8 cups of fruit, sugar and lemon juice in a heavy stockpot over medium heat.12 - 14 cups blackberries, 4 cups sugar, 2 tablespoons lemon juice
- Stir until sugar is dissolved. Continue cooking over medium heat until mixture comes to a boil. Stir every few minutes to prevent scorching.
- Boil until jam is set (220 degrees at sea level and -2 degrees for every 1000 feet above sea level.. 1000 feet 218°). Jam needs to reach temperature in order to thicken. Stir often to prevent scorching. Remove from heat. Ladle into clean, sterilized jars.
- Wipe down rims and add canning lids and rings. Place in a hot water bath and boil jars for 10 minutes (adjust time according to elevation - see notes below)
- Be certain to add some unripened, or reddish berries as well as the ripe blackberries. The unripe berries have higher levels of pectin.
- Cooking time will vary depending on your elevation and your stove.
- I used pint sized jars (2 cups.) You can also use ½ pint size jars.
- Be certain to adjust water bath times according to your elevation.