Straight Up Strawberry Jam

Strawberry Jam
On Thursday I posted a recipe for strawberries in syrup. Here now is my recipe for a very simple but also very excellent strawberry jam. It only has three ingredients (well, maybe four): strawberries, sugar, lemon juice. When you have excellent, perfectly ripe strawberries that you just picked yourself the day before, you don’t mess around.

One of the pleasures of home-made jam, as I said on Thursday, is that you get to keep the sugar low, or at least lower than in most commercial jams, and this jam puts intense strawberry flavour and not sugar front and center. The lemon juice is there for acidity, necessary both to keep you from killing people who eat your jam months after you make it and to help release the pectin in the fruit. Pectin is what you need to get the jam to jell/set and strawberries are not particularly high in pectin. Some/many home canners get around this by using commercially available powdered pectin. I’m not one of these people.

This is not because pectin powder is not “natural” (it is) or some kind of chemical additive (it isn’t); I’m not silly, or at least not in that way. I don’t use it because I prefer to reduce the jam as it comes to the jell point: I get a lower yield than I would if I used commercial pectin, and I spend more time stirring and dodging molten strawberry syrup that shoots out of the pot every once in a while, but I get a more intense jam. At least I like to think so and my family agrees—this is the one jam that rarely makes it out of our home (I give away/swap a lot of other jams, chutneys and pickles). So, how do I get around the low pectin content of strawberries? I add green apple peels. Apples, you see, are very high in pectin—in fact, commercial pectin powder is made from apples.

Anyway, on to the jam!

Jam in ProcessIngredients

  • Ripe, sweet strawberries: 5 quarts, hulled and rinsed.
  • Sugar: 3.5-4 cups (depending on how sweet the strawberries are).
  • Lemon juice: 5 tablespoons.
  • The peel of one Granny Smith apple.

Making the Jam

  1. As with the strawberries in syrup, I start by “macerating” the strawberries overnight with the sugar in a covered glass bowl.
  2. In the morning add the strawberries and the syrup that’s formed to a deep pot and add the lemon juice and the apple peels.
  3. Bring to a rolling boil.
  4. While the pot comes to a boil set out a small bowl with a tablespoon in it and fill it up with ice. Place a teaspoon close at hand.
  5. Once you’ve got a good boil going, start stirring vigorously.
  6. Somewhere between the 18-25 minute zone is when your jam will probably begin to jell. To test, take the pot off the heat, use the teaspoon to remove half a teaspoon’s worth of jam, remove the tablespoon from the ice and add the jam to it and tilt it a bit. If you see the jam thickening and slowing its slide down the spoon as it cools you’re there. Otherwise go on a bit longer and test again.

Four PintsCanning the Jam

The effort of making a tiny amount of jam and a lot of jam is exactly the same (well, except for the berry hulling part) and so you may as well make a lot of it and preserve most of it. This part seems forbidding and scary, but if I can do it, and I’ve not sickened anyone in six years of jam making, so can you. My lawyers have told me to say, however, that by going on you absolve me of all liability.

  1. Clean eight half pint mason jars and wash the lids and rings. I use these jars made by Ball’s (and the relevant rings/bands and lids).
  2. As you get the jam started also get a very large pot of water on the boil alongside. This pot should be deep enough to take the filled jars, cover them with a few inches of water and still be tall enough to not spill boiling water as the jars process. Some people use fancy, specialized equipment. I use a large stockpot and put the jars in a pasta colander insert. You don’t want to set the jars on the bottom of the pot as the heat may crack them.
  3. When the water is almost at a boil, gently lower the jars and rings into the hot water and remove (this is to get the jars hot enough so that they don’t crack when you ladle hot jam into them). If you time things well you can do this part right after testing if the jam has reached the jell point.
  4. Once the jam has set fill the jars up to the top, leaving 1/4 inch or so of headspace.
  5. Once you’ve finished filling the jars drop the lids into the boiling water for 30 seconds or so to loosen the adhesive a bit.
  6. Then place the lids on the jars (wiping them dry first) and tighten the rings—but don’t make them too tight yet.
  7. Put the jars in the colander and place it in the boiling water and process for at least 10 minutes, making sure there is an inch or two of boiling water over the lids at all times. If you want to be safer go for 15 minutes.
  8. Then remove the colander from the pot and using dishtowels or oven mitts carefully remove the jars and set on a cutting board and set aside in a cool part of your kitchen for 12-24 hours. Check that the center of the lids got indented (indicating a proper seal) and now tighten the rings fully. If a jar hasn’t sealed you can either re-process it (maybe with a new lid) or just finish that jar first.

Strawberry Jam


  1. Most recipes will tell you to mash the strawberries before starting to make the jam. I don’t like to do this because I like my strawberry jam to have lots of whole strawberries in it. I mash some against the side of the pot as the jam boils but don’t get too carried away doing it. If you prefer a “smoother” jam by all means mash first—for all I know this may make the jam set faster too.
  2. I usually start out fancy with the apple peel tied up in a bundle and dangled in the syrup. Five minutes after I start stirring the bundle falls apart and the peels disappear into the jam. They’re delicious when fished out as you’re jarring the jam. They’re perfectly fine if they make it into the jars too but will look disconcertingly like human skin when they emerge months later.
  3. Don’t worry too much about getting the jell point right the first few times you make jam. It took me a while to get the feel for it. Your first few batches may be looser or tighter than you like but it’ll still be better than store-bought.
  4. Five quarts of berries should yield anywhere between 4 and 5 pints of jam. I usually plan to put away four 1/2 pint jars and start eating any excess right away.

Coming soon: a slightly more involved pluot jam!


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