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How to Make Plum-Blackberry Jam

The past couple of years I have been experimenting with making homemade jams. If you are new to canning, it might seem a little overwhelming, but if you are interested in getting started in canning, making homemade jam is a great place to start.

I have made several batches of blackberry jam. It really only takes a couple cups of blackberries to make some great blackberry jam. This year I was able to pick my own blackberries (for free!) so I was excited to get started making some jam.

blackberries and plums

The same day I picked blackberries, I was also able to pick some plums. When I got all the fruit home, I had no idea what I was going to do with all of it! I knew I was going to make jam with the blackberries, but had no idea what I was going to do with the plums.

I started to look around online and found some recipes for making Plum-Blackberry Jam. I thought this was an interesting combination, and I was definitely skeptical! I decided to give one of the recipes a try, however, because I didn't have anything else to do with the plums.

For this recipe I used liquid pectin, called Certo Sure-Jell. There are other ways you can make jam, but I have had really good luck with this brand of liquid pectin, so I definitely stick with what works.

blackberry plum jam

When making cooked jam, the main thing to keep in mind is to follow the instructions exactly. When you are measuring, make sure to make exact measurements. I cannot emphasize this enough. It will make the difference as to whether your jam sets or not, and you don't want to go to all that effort and not have your jam set!

For approximately 4 pints of jam (I use pints instead of half-pints because we go through jars of jam very quickly!), you will need:

3 c. crushed plums
1 c. crushed blackberries
7 1/2 c. sugar
1 pouch liquid pectin

Before you start, fill your boiling-water canner half full of water and start it simmering.

Wash and sterilize your jars, lids, and screw bands. The easiest way to do this is run them through the sanitize cycle in the dishwasher and remove them from the dishwasher to use when they are still hot.

blackberry plum jam

To prepare the plums, you first need to peel them. To easily peel plums, let them set in boiling water for approximately 1 minute and then dunk them in ice cold water. The skins will slip right off. Next remove the pits and chop the plums finely.

To prepare the blackberries, rinse them thoroughly and then use a potato masher to crush them in a bowl.

At this point you don't have to have measured perfectly. Mix the fruit together in a saucepan with 1/2 cup water and bring to a boil. Reduce heat, cover, and simmer for 5 minutes.

When you remove the fruit mixture from the pan, measure 4 1/2 cups of the cooked mixture. This is the measurement that counts, and the amount you need to make the jam. Note that you can change the amounts of blackberries and plums to suit your tastes, but the finished cooked mixture should measure 4 1/2 cups.

Measure exactly 4 1/2 cups of the fruit mixture into a saucepot. Stir in the sugar. Add 1/2 tsp. butter or margarine to reduce foaming if desired. Bring the mixture to a rolling boil on high heat, stirring constantly. (Note: A rolling boil doesn't stop bubbling when you stir).

Quickly stir in the package of liquid pectin. Return to a full rolling boil and boil exactly 1 minute, stirring constantly. Remove from heat. Skim off any foam, if necessary.

Quickly ladle mixture into sterilized jars, filling to within 1/8 inch of the tops. Wipe jar rims with a wet cloth to make sure you get a good seal. Place lid and screw band on jars and screw bands tightly. Using tongs, lower jars into canner. Water should cover the jars by 1 to 2 inches. If there is not enough water, add boiling water as necessary. Cover and bring the water to a gentle boil. Boil for 10 minutes (check the chart included with the pectin to adjust boiling times for different altitudes). Remove jars and place upright on a towel to cool completely.

After the jars have cooled, check the seals by using your finger to press down in the middle of the lid. If the lid pops back up, it is not sealed. You can still eat the jam, but it must be refrigerated and eaten within a couple of weeks. Let jars stand at room temperature for 24 hours before moving to storage. This is to make sure the jam sets completely. Do not disturb the jars while they sit. Your plum blackberry jam can be stored in a cool dark place for up to 1 year.

Yield: Approximately 4 pint jars or 8 half-pint jars

So what did my family think? They LOVED it. I also made some plain blackberry jam, and between the two jams, they definitely liked the plum-blackberry the best.

Copyright 2011, Creative Homemaking, LLC. This article may not be reprinted.

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Rachel Paxton
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