How is it that the first fruit of summer turns out to be the star of one of the more difficult jams to make? Doesn't seem fair. Even experienced home food preservers will admit to wrestling with strawberry jam. It's that tricky.
Yet all those gorgeous strawberries are calling out to eager preservers who struggle and then hold a grudge. I'm redeeming canning's reputation with a recipe that puts strawberry jam making in its place. Reliable, consistent and downright delicious — not sad, angst-ridden and frustrating — this recipe takes about two hours over two days, uses common kitchen equipment and results in a reasonable number of ruby-red jars of superb jam.
Getting fruit preserves to set is all about pectin, a naturally occurring element. Some fruits have a lot of pectin while others have almost none. Pectin binds with sugar and lemon juice to form the gel that sets the preserves. Achieving consistent gel when making jam with low-pectin fruits, such as berries, requires nothing more than the addition of a Granny Smith apple. Once it's grated directly into the berry-sugar mixture and offered a long luxurious maceration (rest period), the fruity syrup becomes suffused with the apple's natural pectin.
When that syrup is reduced and the berries are incorporated, the mixture comes together into a not-too-firm, berry-studded, tart jam.
Adding an apple is only half the battle; one must deal with nuance as well — a nice way to say that every batch has quirks. Too little boiling and the preserves will be runny; too much and they will be bouncy. Wait for the foam on the surface to nearly clear, at which point the jam will be set. Any bits of thick foam that persist are easily dispersed with a pinch of butter and a lot of stirring.
To understand jam making takes experience. Whatever you capture in the jar will be delicious. If the jam turns out a bit loose, call it sirop and pour it, warm, over waffles. If it's rubbery, warm it in a saucepan and add water until it has thinned considerably. Bring to a boil, cool, then ribbon through softened vanilla ice cream. Refreeze the ice cream, and declare victory.
The accompanying recipe makes rich preserves. Please do not alter the amount of sugar. You might think it would be "healthier" to do so, but that balance of fruit, sugar and lemon juice is the very essence, the science, of jam making. When the ratios are changed, the gel, the color, the flavor and the shelf stability of the jam are at risk.
Strawberries grown locally are plump and juicy and irresistible. They have not been refrigerated in the deep cold of a long-haul truck. Instead, they are picked when ripe and sent right to market. Taste one before you commit. Seek out ripe, locally grown, recently harvested, flavorful berries. One-quarter of them should be slightly underripe.
It's a great time for pick-your-own farms, roadside stands and farmers markets, where the air will be full of that sweet berry smell. Open a jar of this jam in gray, bleak February, and it will transport you.
Just Right Strawberry Preserves
3 1/2 to 4 half-pint jars
Make sure to use about three-quarters perfectly ripe berries and the rest underripe; the latter have more natural pectin, further contributing to a proper set. You will need a candy thermometer and 4 sanitized half-pint jars with new lids and rings; see the NOTES, below. If you plan to do lots of canning, you might want to invest in a preserving pan, which is recommended for this recipe.
MAKE AHEAD: The uncooked apple-strawberry mash needs to rest in the refrigerator for 2 to 24 hours. Store the preserves in a cool, dark place for up to 1 year; refrigerate after opening.
From Cathy Barrow.
3 pounds (about 2 quarts) strawberries, hulled
3 cups granulated sugar (organic or raw may be substituted, but use weight, not volume; 26.4 ounces)
Juice of 1 lemon
1 Granny Smith apple
1/2 teaspoon unsalted butter (optional)
Combine the strawberries, sugar and lemon juice in a large mixing bowl; use a potato masher or broad, nonflexible spoon to mash the fruit into the sugar just enough so that some larger pieces of berry remain.
Use the large-holed side of a box grater to grate the (unpeeled) apple directly into the bowl, turning it once the core is exposed. Stir to incorporate thoroughly. Cover and refrigerate for 2 to 24 hours.
Pour the mixture into a colander set over a heavy-bottomed 5-quart preserving pan or pot. Stir, encouraging the collected syrup to fall into the pan or pot. Remove the colander, seating it inside the bowl to capture any remaining syrup; add that to the pan or pot as needed. Leave the solids in the colander while you cook the syrup.
Clip the candy thermometer onto the preserving pan or pot; cook over high heat to bring the syrup to 220 degrees, the soft-ball stage in candymaking. The syrup will foam and rise up, so stir it from time to time. Add the berry mixture to the syrup, stirring as the preserves return to a rolling boil. The preserves will foam and rise up as the water boils away and the set is achieved. Once the foam is nearly gone, the jam will be done. Turn off the heat and test the set (see NOTES, below).
Once the set has been achieved, add the butter, if desired. Stir well and thoroughly without scraping the sides or bottom of the pan or pot until the last bits of foam have disappeared.
Ladle the preserves into the sanitized jars, leaving 1/2 inch of head space. Run a chopstick or flat plastic knife along the inside of the jars to dislodge any air bubbles. Clean the rim of each jar, place the warmed lids and finger tighten the rings (not too tightly). Process in the boiling water bath for 10 minutes (see NOTES, below). Turn off the heat and use a jar lifter to transfer the jars to a clean, folded dish towel to cool for several hours.
Label and date the sealed jars. Store in a cool, dark place for up to 1 year. Refrigerate after opening.
NOTES: There are three ways to test the set. The sheeting test entails stirring the preserves, then lifting the spoon to watch the jam sheet off the spoon, flowing slowly and collecting along the bottom of the spoon before languidly dripping back into the pot. It should look like jam, not like syrup. The sheeting test takes a practiced eye.
The cold plate test is a surefire method of testing the set. Before beginning to cook the jam, tuck 3 small plates and three spoons into the freezer. Once the preserves seem to be set, use a cold spoon to place a tablespoon or so of jam on the plate. It should set instantly. Press against the blob of jam. Does it resist just a bit? Wrinkle a little? It's done.
The third method is the lazy cook's cold-plate test. Remove the preserves from the heat and cool for 3 to 5 minutes. Press against the surface of the jam. Does it resist just a bit? Wrinkle a little, as though a very small pebble has hit the surface of a pond? The jam is ready.
For jam that is not yet set, return the preserves to the stove; cook for 2 to 5 minutes at a strong, hard, foamy boil that rises up no matter how much you stir; then test again. Stop and start the cooking process as many times as necessary until you are satisfied with the set. The jam will set further as it sits, so err on the side of a loose set vs. a very firm set.
Water-bath canning safely seals high-acid, low-pH foods in jars. The time for processing in the water bath is calculated based on the size of the jar and the consistency and density of the food. For safety's sake, do not alter the jar size, ingredients, ratios or processing time in any canning recipe. If moved to change any of those factors, simply put the prepared food in the refrigerator and eat within a week.
Fill a large canning kettle or deep stockpot two-thirds full with water. To keep the jars from rattling against the pot, place a rack in the pot. (A cake rack works well; a folded dish towel is equally effective.) Sanitize the jars in a short dishwasher cycle or by boiling them in a canning kettle or pot for 10 minutes. Fill a small saucepan with water and add the rings. Bring to a boil over high heat, slip in the lids and turn off the heat.
Use a jar lifter or tongs to lower the filled, sealed jars into the boiling water bath, keeping them upright. When all of the jars are in place, the water should be 1 to 2 inches above the jar tops. Add water as needed. Bring the water to a low boil before starting the timer for processing.
At the end of processing, turn off the heat and let the jars sit in the water bath until the boiling has stopped. That will reduce siphoning, in which the food burbles up under the lid, breaking the seal. Use the jar lifter or tongs to transfer the jars to a folded towel, keeping them upright. Leave the jars until they have completely cooled, at least 12 hours. Remove the rings and test the seal by lifting each jar by the lid. The lid should hold fast. Label and store in a cool, dry, dark space.
Nutrition Per tablespoon (based on 4 half-pint jars): 45 calories, 0 g protein, 11 g carbohydrates, 0 g fat, 0 g saturated fat, 0 mg cholesterol, 0 mg sodium, 0 g dietary fiber, 11 g sugar