I am about to let you in on a very badly kept secret: I am crazy for the foods of Summer. Fresh Corm on the Cob. Tomatoes. Avocados. Berries. Peaches. Watermelon. I could honestly eat every meal at the Farmers Market, all Summer long. I am a big believer in eating seasonally; a raw tomato or ear of corn eaten in December isn’t worth eating, in my opinion.
But what if you could capture some of the essence of Summer food and enjoy it during the long, cold, snowy winter to come? That’s what canning, jamming and freezing are all about. It’s amazing to me how many people are intimidated by the idea of canning. Let me tell you something, if you can knit a sweater on-gauge or thread a sewing machine, you can successfully can. And once you taste the jam, tomato sauce and other pantry staples you can make at home, you’ll turn your nose up at the sorry substitutes you can find in the grocery store.

Jam is the best jumping off point for canning because it’s dead easy, delicious and makes wonderful gifts when the holidays come along. There are about as many ways of jam making as there are cooks who make it. I have a few cookbooks specific to preserving and all advocate different methods, sugar-to-fruit ratio and cooking times. I experimented for years before coming up with my own tried and true method. This week, we’re going to make three kinds of jam: blueberry, strawberry and peach. Blueberry jam is the easiest of all so we’ll start there.
First, a few basics that apply to all jam-making and canning. Before you start to make jam your kitchen should be scrupulously clean. You are going to be storing your jam at room temperature for many, many months, and it is essential that the jam be as bacteria-free as possible from the get go. I usually do this the night before so I’m ready to get going first thing in the morning. All surfaces should be sanitized, along with the sinks you’ll be using.

While you’re cleaning, fill the dishwasher with your canning jars and run it. I don’t wash the rings and lids that come with the jars in the dishwasher: they will be sterilized later, along with the jars themselves. This wash it remove the Christmas-morning-plastic-doll smell that comes with new jars. No dishwasher? No problem. Just wash the jars by hand and allow them to air dry.
While we’re on the subject of jars, I tend to use half-pint sized jars for jams and preserves, reserving pint and quart sized for tomato sauce and other savories. Half-pints are a good size for giving and tend to get eaten up quickly, whereas a pint jar may go moldy in the fridge after it’s been opened for a month or two.
Canning jars are available at Walmart and Target, along with many hardware stores. Check the Seasonal section of the store if you have trouble locating them. You can also order both Ball and Mason jars and have them delivered. The larger sized jars come in two mouth sizes, regular and wide, which are standard to all brands. I prefer the wide mouth jars when I can get them. Just be sure you know which size mouths you have when buying replacement lids.
As far as specialized equipment goes, I highly recommend a jar lifter, and a wide-mouth canning funnel. You will need a large stock pot for water processing your finished jam, but the pot you use for making spaghetti in will work just fine.

For this recipe, you are going to need 8 dry pints of blueberries. I tend to make blueberry jam when I go blueberry picking or when blueberries go on sale at the market for 2 for $3.

Put your blueberries in a colander and pick through them, removing any unripe, green berries, stems and damaged berries. Handle the fruit gently.


Next, rinse your berries under running water. Again, be gentle when rinsing. You’re just trying to remove any leftover sand or grit from the fruit.

In addition to the blueberries, you will need cane sugar and two lemons or limes for your jam. I prefer limes because I think it make a more interesting jam, but lemons are more traditional. You may be wondering why you won’t be needing commercial pectin. I prefer jam made without added pectin- I find the taste slightly off-putting- and almost all fruit contains enough natural pectin to jam without it.

Did you know that in order for a commercial product to be labeled “jam” the FDA requires it to contain equal parts fruit and sugar by weight? That’s the reason most jam is so teeth-achingly, cloyingly sweet. One of the joys of making your own is that you get to control the amount of sugar in your jam. I like my jam to be a bit on the tart side, so I added 3 cups of sugar to my 8 dry pints of blueberries.

Next, juice your lemons or limes into your bowl of berries. Or, if you are smarter than me, juice your citrus in to a small bowl and then pour the juice over the berries. This will save you time hunting for the seed that slipped in by mistake.

Next, add the zest of one lemon or lime to your bowl. (You can zest one of the ones you’re going to juice.)


Give everything a good stir. You will have a bowl of sugar-coated blueberries, which is exactly what you want.

Cover the bowl with a tea towel and allow it to sit for at least 4 hours, preferably overnight. While your berries wit in the sugar, they are macerating.If you have room, you can macerate your fruit in the fridge but it will slow the process so increase the time to at least 8 hours. When it’s time to cook the jam, you’ll find that your dry bowl of berries in now a bowl of berries swimming in beautiful, purple juices.

Now we’re ready to cook our jam. You want a shallow-ish, wide pan. My preferred jam making pot is about 6 inches deep and 20 inches across. The wider the pan, the faster evaporation will happening during the cooking process. We want to cook the jam quickly in order to retain as much of the fresh fruit flavor as possible.

Place a colander into your jam pan and tump the blueberries into it, straining the juice into the pan, reserving the blueberries.

Put the pan containing the juice on the stove and bring to a boil over high heat.
Continue boiling over high heat until the liquid has reduced by about half. The time this takes will vary depending on the size of your pan and the amount of juice but it will be in the neighborhood of 15 to 20 minutes.
While you’re waiting for the juice to reduce, bring a stock pot of water to a brisk boil over high heat. Add the jar lids and rings, canning funnel, ladle and a skimmer or slotted spoon to the pot. Cover and let boil for 15 minutes, then pour the contents into a clean colander in the sink to drain.
Put your cleaned jars onto a sheet tray and place them in the oven that has been preheated to 400 degree. This is my preferred method of sterilizing jars, as I find that boiling empty jars can lead to chips and breakage. Remove the jars after 20 minutes and allow to cool on the tray.
Once your juice has reduced by half, add the blueberries and any remaining juices to the pan and return to a rolling boil, stirring occasionally. Cook for about 20 minutes or until the jam reaches 220 degrees on a candy thermometer. If you don’t have a candy thermometer you can easily test to see if your jam has reached the “set point” by placing a small plate in the freezer for about 10 minutes. When the plate is chilled, spoon a drop of the jam onto the plate like this:

If the jam is ready, it won’t run back together when you swipe a finger through it. It will wrinkle a bit and feel firm.

When the jam has set, remove from heat immediately and skim off any foam that may have formed, using your skimmer of slotted spoon.
Now we’re ready to jar our jam! You’ll need your colander full of sterilized rings and lids, the sterilized ladle, 10 sterilized jars, a slightly damp, clean dish towel, the sterilized canning funnel and your pan of jam.
Fill your jars, leaving 1/2 inch of head space empty.
To keep things neat, have the next jar ready to rest the funnel in as you fill each jar.
Carefully wipe the rim of each jar before putting the lid on and screwing down the ring. Even small amounts of jam on the rim can prevent the jar from sealing properly so don’t skip this step!
Continue until all your jars are filled. This recipe made 10 full jars for me, with a little left over that I put into directly into the fridge for immediate use. Now we are ready to water process the jars. For some reason, this step scares people but nothing could be simpler. Honest! Just bring your large stock pot of water to a boil over high heat.
Once the water is at a rolling boil, submerge a dish towel in the pot. This is going to keep your jars from knocking together too much and breaking.
Carefully lower all the jars into the pot of boiling water.
Once all the jars are submerged and the water has returned to a boil, set a time for 10 minutes. It’s important that the jars are in the pot at a boil for the entire 10 minutes. The water processing ensures that the entire jar reaches the appropriate temperature to kill any remaining bacteria. Carefully remove the jars from the boiling water and allow to cool. While the jars are cooling, you will hear the tops of the jars popping. This is normal and just means that you have successfully created a hermetic seal on the jar.

Voila! You made blueberry jam.
Tomorrow we’ll make Strawberry Balsamic.