All the recipes I found on the interwebs showcased the sugar much more than the fruit - some, in fact, advised a 5-1 ratio of sugar to fruit! Crazy! So, remembering June Taylor's class that I took last year, I took her advice and reduced the ratio to almost the opposite of that and added a little lemon zest for another layer of interest. I didn't use pectin, either; the resulting jam didn't jell well, it's a little loosey-goosey but, oh, the fresh, bright flavor and the rich, red color! When My Beloved's took his first bite, he exclaimed, "Oh, wow!" I'm very proud of that.
I used smallish jars because we don't eat a lot of jam and I wanted to be able to pop open a fresh one from time to time. I got seven 4-ounce jars from three baskets of ripe berries. I didn't process them in a water bath* either, just took the jars piping hot from the dishwasher, quickly filled them with searing hot jam to within 1/4" of the top, wiped the lips with a damp paper towel, and put on the sterilized lids, screwing the bands down firmly but not tightly. When all jars were filled, I blanketed the jars in towels to keep the heat in longer and to slow the cooling. All the jars sealed well - I'm confident that they will keep for a long, long time.
Here's the recipe I devised:
Zesty Strawberry Jam
8 cups (three baskets) of strawberries, hulled (= about 5 cups of mashed berries)
3/4 cup sugar
1/4 cup lemon juice (about two lemons worth)
2 lemons worth of microplaned zest (very finely grated zest - it looks almost like pollen)
Hull strawberries and mash them with a potato masher until they are lumpy and liquid. Add the sugar, lemon juice and lemon zest. Stir to dissolve the sugar and leave the fruit to macerate while you prepare your jars, bands and lids. You can leave it overnight if you want, but I'm always too impatient.
Prepare the jars and bands ahead by washing on hottest setting of the dishwasher. Leave the dishwasher closed after the cycle. Have a pair of heatproof gloves on hand (the jars will be piping hot once you fill them), plus several damp paper towels for wiping the rims of the jars, a small ladle and a large wooden cutting board (the jars will be too hot to put directly on the counter - they could shatter if your counter is too cold or hurt your counter if it's not heatproof). Place lids in a small pan of water and boil briefly. Leave the lids in the hot water.
Bring the fruit slowly to a boil, stirring to make sure the sugar is dissolved, in a heavy-bottomed pot. Once the sugar has completely dissolved, raise the heat to a full boil and let 'er rip, stirring more or less constantly, until the berries are making thick, shiny bubbles that pop but leave a small "hole" before filling up again. To test that they are ready, put dab of the juice on a plate and, when cooled, push it with your finger. If it "wrinkles" ahead of your finger and doesn't run to fill in where your finger was, it is ready. If it runs to cover your finger mark, boil it some more. Mine took about 20-30 minutes, give or take. Keep stirring while it boils to keep from burning on the bottom.
Once the jam is ready, pop open the dishwasher and quickly remove a couple of jars, setting them on the wooden board. Close and lock the dishwasher again. Working quickly with the heatproof gloves on, ladle the jam into the jars, filling to within 1/4" of the top. Carefully wipe any spills from the lip of the jar with the damp paper towel, replacing the towel as it gets soiled. Fish a lid out of the hot water with tongs, shake it off and fit it to the jar, then put on the band and screw it down firmly but not tightly (you want it to make the seal but you don't want it to dislodge your lid once it is cool and the band is removed). Repeat with the rest of the jars.
Once the jars are all filled, gather them together and cover them with a thick blanket of kitchen towels, inches thick if you have that many, or regular towels. The idea is to keep the heat in as long as possible and to slow the cooling so the jars have plenty of time to seal.
*Most home canning instructions will recommend that you do this processing to insure that no bacteria are alive in the jars. It is good practice and you should do it. Do as I say, not as I do.
If you skip this step, however, just make sure your jars have sealed by removing the band and, holding the jar by the lid, give it a pretty good shake, holding your other hand under it just in case. If the jar falls off, it didn't seal. If it didn't seal, refrigerate it and eat that jar first. If I give away my jam, I always warn the recipient to throw it away if they have any doubts when they open it.