blackberry jam

Oregon Blackberry Jam

I made twenty-three jars of blackberry jam last weekend. I am very glad to not be making blackberry jam this weekend. 
It’s not that it’s hard… just time-consuming. Well worth it, though, to have homemade jam all winter and lots to give away as well.

I started with one flat of berries on Friday. We had breakfast for dinner that night. Bacon, eggs, and pancakes with fresh blackberry jam. I was quite satisfied.

Saturday, Bob brought me two more flats. He “got a deal”. He likes blackberry jam a lot.
I made him help me. Turns out, he’s pretty good with the food mill. 
 The girls got in on the action. We made them wash their hands a lot.


Sour berry face. Sort of like bitter beer face. 


My beautiful child.
8/29/2018 – Hi. I’ve updated this post to include detailed instructions for canning which I borrowed from my Raspberry Jam post. So, some pictures are of raspberry, not blackberry, jam but the process is the same. 

blackberry Jam

(makes about 4 pints)

4 1/2 pounds blackberries 
5 1/2 cups sugar 
1/4 cup fresh lemon juice 

Special Equipment

large stock pot/canning pot (at least 12-quart capacity)
*large, heavy-bottomed  stock pot or enameled Dutch oven (6 – 8 quart)
plastic canning basket
jar tongs/grabbers
large funnel
canning jars (I use 8-ounce or 12-ounce jars but you can use any size, keeping in mind you’ll end up with approximately 4 pints of jam)

*It’s important to use a non-reactive pan for the jam. Stainless steel and enamel are good choices. Aluminum and iron are reactive, don’t use them to cook the jam (They’re ok for the canning pot filled with water).
blackberry jam
Fill a large stock pot/canning pot with water (leave about 4″ at the top) and set it on high heat to boil. This could take a while so you want to start ASAP before you start the jam. Have your canning jars clean and ready to sanitize in the boiling water. You can also use your dishwasher to sanitize the jars before filling, just make sure you time it so they are still a little warm when you fill them with jam. You’ll still need the pot of boiling water for the sealing process.

 Place a small glass/ceramic plate or ramekin in the freezer to chill for testing the jam.

Pick through berries. Imperfect ones are fine but remove any moldy ones as they will affect the taste of the jam. Give the berries a rinse in a large colander/strainer, then drain.
blackberry jam
 In a large, heavy-bottomed stock pot or enameled Dutch oven, mash the berries with a potato masher.

OR: If you like fewer seeds in your jam, do as I made Bob do and run the blackberries through a food mill before placing them in the pan. Add about half the seeds back into the blackberry puree then discard the rest of the seeds. It’s sort of high-maintenance but well worth the effort to me.

Add the sugar and lemon juice, place the pan over medium heat, and cook, stirring gently, until the sugar is dissolved. Turn heat up to medium-high and bring the mixture to a rolling boil.

Continue to boil the jam over medium-high heat until it thickens, stirring often. The timing on this varies depending on how high your heat is, how much moisture is in your berries, etc..

As soon as the water in your stock pot begins to boil, place your lids and jars in a plastic canning basket  (I sort of piled the jars on in the water because they didn’t all fit in the basket) and submerge them in the water, boiling for at least 10 minutes. If you’re at a higher elevation like I am, add one minute for every thousand feet. This should sterilize them properly.

Lay out a large dishtowel to place the sterilized jars and lids on.
Meanwhile, your jam is cooking. You’re multitasking – you’re doing great! Remember, if you feel your jam is cooking too fast and you’re busy with your jars, you can simply turn down the heat to a simmer to keep it from thickening too fast then turn it back up to a boil when you’re ready.
When you start to notice a thick consistency, take your chilled plate/ramekin out of the freezer and place a small spoonful of jam on it. If it’s ready, it should mound up and not spread all over the plate. Also, if you run a finger through it, the path should be clear and not spread. When it passes the tests, go ahead and remove the jam from the heat.
By now, your jars should be sterile. Take them out carefully, leaving the stockpot full of hot water for the final step of sealing the jars. Place them upside down on a towel, the glass will dry quickly but you’ll have to dry the lids with a clean towel.

Using your funnel (very important piece of equipment) and a ladle or a heatproof measuring cup, fill the dry jars leaving about one-quarter (no more than one-half) of an inch headspace at the top.

Fill all the jars, top with the lids and seal, a little more loose than tight, with the rings. If you don’t fill all the jars full, place remaining jam in the refrigerator and don’t worry about sealing the lid.

To seal the lids on the jars for storage, place them in the basket and submerge in boiling water. Boil for at least 10 minutes, longer if you are at a higher elevation. I just go ahead and boil mine for 15 to be sure.

Remove them, carefully from the water and wait for the “pop” sound you should hear when the jar is sealed. If you fail to hear it, you can check the middle of the top of the jar. If it’s still raised, it’s not sealed.
If it’s indented and doesn’t pop back up when pressed, it’s sealed. Sometimes it happens in the first couple minutes, sometimes it takes a lot longer so don’t panic if it doesn’t seal right away.
The sealed jars should keep the jam well in your pantry until next summer when it’s time to make more.
Here’s a link for those of you who want to learn more about canning.
“Get people back into the kitchen and combat the trend toward processed food and fast food.”