With fruit at its peak, make your own jam

When I was still half a block away from my aunt's house, I could smell the sweet, inviting aroma of homemade preserves wafting out of her kitchen. Sure enough, when I arrived, I'd see two large pots simmering on her wood-fired stove in the sweltering kitchen.

She'd dip a spoon into a pot and smear hot, magenta-colored jam on the heel of a fresh loaf of bread for me. Pleasantly tart rosehip jam on warm bread – heavenly! But that was in the 1950s. It's something you can't imagine today, unless you're one of the few who make their own jam.

Good jams and marmalades are not easy to find. Supermarket shelves are filled with a large selection of them, but most taste rather ordinary. Even expensive, high-quality jams aren't as good as homemade ones.

Why not try making your own? It's not as difficult as you might think. And summer is the ideal season for jam-making, with an abundance of ripe fruit in grocery stores and farmers' markets.

Jam-making is not hard, and it doesn't have to be time-consuming: I preserve six 12-ounce jars of wild blackberry jam in just over an hour – from washing the berries to labeling the jars.

Some people make no-cook freezer jams, which are not particularly good. They never develop the flavors that only the cooking process brings out.

There are two basic cooking methods for jam-making: You can use commercially available packages of pectin to hasten the thickening of fruit into jam. Or you can boil down the fruit and liquid the old-fashioned way, as my aunt did, until the mixture reaches jam consistency. This takes longer, but it's the method that I prefer for many reasons.

If you use pectin, you must maintain the correct chemistry of all ingredients or the concoction fails. You need to add the exact amount of sugar according to the package and stir continually. The process is quick, but it doesn't always yield the best results.

Evaporating the excess liquid by boiling is much slower, but the difference in flavor between the pectin and boil-down methods is substantial. Jams made using pectin can taste unfinished and flat because more liquid remains in the jam, diluting the flavor.

Slow-cooked jams, however, acquire a rich, concentrated fruit flavor because more liquid is boiled off. As the fruit mixture passes the boiling point, the sugar starts to caramelize, the color darkens, and flavors intensify. You end up with less jam but more flavor.

When I first realized the difference in taste, I discarded all my pectin packages.

The tricky part about the slow-boiling method is determining when to stop cooking it. (It can take anywhere from 40 minutes to an hour to get the right consistency, depending on the juiciness of the fruit.) If you stop too soon, you'll have a syrupy concoction. If you wait too long, you end up with a taffylike mixture that's hard to spread.

To get the jam just right, I rely on two methods. First, I use a good candy thermometer to check that the temperature has reached 220 degrees F. Then I test it by dropping a bit of the cooking jam on a cold plate and letting it cool for a minute or two. Is it too thin or too thick?

I adjust by cooking the jam longer or adding a small amount of water. (If you don't have a candy thermometer, the plate test is accurate enough on its own.)

It is always safer to shoot for a little too thin (it thickens in the refrigerator) rather than too thick jams.

As soon as the jam is just right, pour it into clean jars. There's no need to sterilize the jars, just wash jars and lids thoroughly with soapy water and rinse. Then seal and label them.

Now they're ready to share with someone you love.

6 cups ripe blueberries
3 cups sugar
1/4 cup fresh lemon juice
1 tablespoon grated orange peel

Combine berries and sugar in a one-gallon heavy pot and bring to a boil. Cook, uncovered, over medium-high heat for 35 to 40 minutes, stirring every few minutes. Watch to make sure the mixture doesn't boil over and adjust heat accordingly. Meanwhile, place a plate in the freezer or refrigerator to cool for use in testing jam later.

After about 35 to 40 minutes, begin testing the jam's consistency by dropping a little onto the cold plate. Wait a few minutes until the jam cools to determine if it is too thin or too thick. Adjust by cooking longer or adding a little water. (Jam may need to cook closer to an hour.) If you have a candy thermometer, test temperature: It should be 220 degrees F. (If you don't have one, the plate method is sufficient.)

When jam is ready, add lemon juice and cook a few more minutes, stirring until jam thickens up again. Check again for consistency. When it's ready, remove from heat, stir in the orange zest, and pour into clean jars, leaving a little extra room at the top.

Wipe jar edges clean and seal them with clean lids. Makes about 3 to 4 cups. Jam can also be frozen in freezer-safe containers.

(Note: For pure blueberry jam, simply omit the lemon juice and orange peel.)