The blackberries kept me busy. Since other berries aren't happening this year, we are going to have our main stock of jam to get us through winter from blackberries. Thankfully we all love blackberries in our house. And a lucky side effect from four gallons of blackberries is pie too
But this post isn't about pie. This post is about jam and the thirty six half pints I've canned. I'm unsure if I'm adding more at this point or not.
If you don't have access to fresh blackberries you can also use frozen blackberries and still get great jam.
You start with your jam making process by picking over your berries and discarding any that aren't fully ripe. Blackberries must be black all over and even a tiny little red spot on a berry can cause the berry to be less sweet and slightly bitter. No amount of sugar is going to cover up that flavor either. Discard any berries that are unripe.
You need some pectin. I always use boxed powdered pectin. Making my own from green apples is a ton of work that isn't worth it to me. Jam is already a sometimes food since it is full of white sugar, so adding powdered pectin isn't a big deal. You will also need apx 9 half pint jars for this method.
First thing is you need to check your jars to make sure there are no chips, cracks, or other damage. You also need new lids and some rings (these can be used dozens of times) Lids must be new every time you process food because they can only form a proper vacuum seal one time. Wash all of these in hot soapy water and rinse well.
Next you need to bring some water to a boil in a canner or a very large pot that will cover the tops of the jars by at least 1 inch. This takes a while so you might want to bring the water to a boil ASAP. You also need another pot of very hot almost boiling water to keep your jars in to keep them sterile. And another of hot, but NOT boiling water to keep your lids and rings in.
Now for the fruit. You should have picked over and rinsed 2 quarts of fruit at this point. Mash the fruit with a potato masher 1 cup at a time.
You want to use a potato masher because if you puree it in your blender or food processor your jam will separate in the jars. 2 quarts will yield about 5 cups of mashed fruit. Bring that to a boil with your box of pectin. You need to boil this until it is at a full rolling boil, which means that it is still boiling all the way through as you stir it. While you are boiling this measure out seven cups of white sugar.
After your jam is at a full rolling boil add your sugar. Remember that this much sugar is not going to boil until well over 212 degrees so you need to be very careful as jam is VERY hot. You need to return the jam to a full rolling boil and boil for one minute after it reaches this stage. At this point you have jam, though it is very hot. You can put it in jars, put lids on it and freeze it. However you cannot store it on a shelf until you process it.
Ladle your jam into your sterile jars with a soup ladle and if you like a canning funnel (a funnel with a mouth that fits perfectly into a jar). After you jars are all filled put a lid and ring on each jar and tighten, but not to tightly as you still want air to be able to escape. You want the ring tight enough that it will hold the lid firmly in place, but loose enough that air can still escape.
Put in your boiling water canner and return the water to a boil for ten minutes. (Canning tongs are almost a requirement)
After your cans are out the lids will start to pop. You can hear them quite clearly. To check and make sure the jars were all processed correctly you should press down on the lid after the jars are cooled. If the lid still has give, then they haven't processed properly and need to go right in your refrigerator. If they have, mark them with the date and store in a dark cool pantry or shelf. They will last one year.
If you ever open a jar that sprays anything at you, smells off, or anything of the like do not eat it. Throw it away and use bleach on any surface that the food or juice may have touched. This is a bad jar.
After all this work (which only takes about 30 minutes active time) you'll be rewarded with delicious jam, and it is just beautiful!