Alright, so we didn't get together and guitar-strum our way to any sweet tunes, but the Five Star Club (culinary student club on campus) did organize an afternoon jam workshop with the legendary professor and veteran jam-maker, Ms. Barbara Haimes.
First we were led through a cooked-fruit jam demo involving apricots (although any ripe fleshy fruit of your choice would work). The fruit was cut up into small pieces (the smaller the pieces, the more texturally consistent to mush the jam will be) and cooked over medium heat. No flavoring was added since the fruit was ripe enough, but this is of course up to individual taste.
In technical terms, the fruit was cooked till softball sugar stage (~240° F), which made intuitive sense to me after pastry class because that's the temperature where cooked sugar syrup will coalesce into a soft ball if you drop it into cold water (which is the same consistency you want your jam to be). Ms. Haimes being the expert she is, could tell the doneness of cooking just by observing the foaming and bubbling and then testing by spoon (letting some of the liquid drip off a spoon and watching the viscosity).
After cooking, the jam was scooped/funneled into sterilized jam jars (ideally along with the noyaux, or inside of the pit, which imparts flavor although it cannot be eaten because it contains trace amounts of cyanide) and sealed.
Then we moved onto making freezer jam because it was logistically easier for everyone to participate.
To make freezer jam, first find the ripest (and/or most organic) fruit you can. This is why summer is a good time to jam, as it allows you to taste the ripe sweetness of summer fruits later on, even in the dead of winter. We used fresh-picked strawberries.
Clean and cut the fruit into pieces, then mash them to a pulp. A potato masher works well for this.
Sugar and sour the berries to your taste. The goal is to simply enhance/complement the ripe fruit's flavor, not to cover or overpower. Here somebody used organic cane sugar and lemon juice, although others did more exotic combinations such as honey and balsamic vinegar.
Then add pectin, which is the gelling agent that solidifies the mash into a more solid jam-like consistency. Pectin packets can be purchased in any supermarket, though pectin can also be made at home with green apples, as it is naturally found in certain fruit skins. We used Sure-Gell (grocery store-bought) and Pomona's Universal Pectin (which is a little more difficult to use but is free from preservatives and other pesky ingredients). The Sure-Gell was mixed over the stove but Pomona's required a food processor to blend and the addition of calcium water for activation.
The mash and pectin mixture was stirred until some gelling started to take place, then everything was scooped/funneled into containers. Jam funnels are different from regular funnels in that the opening is a lot wider.
Everyone got to take a few containers home. The jam had to sit out for 24 hours in order to fully gel, but after that one could either keep it in the refrigerator for 2 weeks or in the freezer (hence the name of freezer jam) for up to a year.
I kept mine in the fridge and promptly served it over French toast the day after it gelled up. Mmm-mmm-mmm!