Summer in a Jar: Blackberry Jam

August 31, 2009 | By | Comments (6)

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Summer hasn’t really begun for me until I’ve picked a bucket of fresh blackberries. In Northern California blackberries are everywhere, the thorny branches growing wild in the hills or climbing around backyard fences. They’re more like a weed than a treasured fruit. Ever since I could walk I’ve picked the plump berries with purple-stained hands, eating one for every berry that ended up in the bucket. These days when I see a blackberry bush I think of the puff pastry turnovers, pies, or jars of jam I’m going to make. Fresh blackberry jam just might be the world’s best breakfast food, preferably eaten with a spoon directly from the jar. Once you’ve tasted homemade jam you’ll never buy it again. It’s a breeze to make; just pick a cool day and get over your fear of canning. (For the best canning tips get a copy of The Joy of Cooking: All About Canning & Preserving, which has easy, step-by-step instructions for sterilizing the jars. If you plan to make only one batch of jam and eat it within one week, there is no need to sterilize the jar; you can store it in a bowl.)
Making jam requires choosing one of two paths: pectin or no pectin. Pectin, a naturally occurring substance in fruits, acts as the thickening agent in jam but purists love the slow-cooked, pectin-free method. The pros and cons of pectin require a whole other blog, but suffice to say using pectin thickens the jam more quickly so there is less of a cooked sugar flavor you get from slow cooking. I decided to go pectin-free and was happy with the result. I also left the seeds in, because I love that almost nutty texture of berry jam. My last tip would be to play around with the amount of sugar you use; most recipes call for a 1:1 ratio of fruit to sugar, but if you have very ripe fruit you might want to reduce the sugar. I found it almost too sweet for my taste, although my friends and family adored it.

2 cups fresh blackberries, washed and air-dried
2 cups sugar (adjust this as needed)
1 teaspoon lemon juice

Sterilize the jam jars and set aside.

Place the berries in a stockpot and crush them with your hands. Add the sugar and lemon juice. Turn the heat to high and bring to a boil, stirring to combine the berries and jam. Once it boils turn the heat to medium-low and cook for about 15 minutes, stirring frequently. Skim any foam off the top.

To test if the jam is set, I use the refrigerator method: spoon a little jam on a plate and turn off the heat. Place the plate in the ‘fridge for a few minutes. If the mixture gels (i.e. doesn’t run off the plate when you hold it sideways) the jam is set. If it doesn’t gel, keep cooking the jam in 5 minute increments and keep testing. Once the jam has set turn off the heat and carefully spoon the jam into the sterilized jars. Proceed with canning as directed. Or simply spoon the jam into a jar or plastic container and keep it in the ‘fridge for up to 1 week.

Note: This recipe only makes about 2 medium-size jars of jam. I think if you’re going to go to the trouble of making jam you should go big, so I used 20 cups of berries and ended up with about 12 small jars of jam. Give homemade jam as a gift and you’ll instantly have more friends.


  1. rob

    It’s true — someone gave me homemade jam and it was the best gift ever!

    August 31, 2009 at 9:41 am
  2. Scromp

    That is such a good picture, makes me hungry. Personally, I’m on the sweeter side of the jam taste profile. But those are some juicy looking blackberries.

    August 31, 2009 at 12:42 pm
  3. Hannah

    Yum! We just planted two little blackberry plants in our backyard this spring. Our yield this summer: exactly 4 blackberrys!!! Pruning and time I guess! Will definitely use this reciped once our plants start producing!!!

    September 1, 2009 at 4:14 am
  4. Donna Wayane

    Am thoroughly enjoying the “You’ve Got To Taste This” weekly blogs from Laura Haddad. This weeks blackberry jam recipe and comments sent me up the hill to my local blackberry patch.

    September 1, 2009 at 9:24 am
  5. Vee

    I am a newby at making jam, so this no pectin recipe is very helpful. I love the Jam test method you describe too! I look forward to reading more of your blogs for other great hints and recommendations. thx

    September 10, 2009 at 12:20 pm
  6. Glass Jars

    We make our own jams, they are loads better then the supermarket, fresher and you know whats going in them. Got to say i prefer strawberry though.

    September 30, 2009 at 6:51 am

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