This is a mere guideline. If you're not sure about this, but want to try it anyway, roast a small cantaloupe. If you're feeling a little more devil-may-care, roast a big one.
Gardening is an act of faith. You plant seeds. They sprout or they don't. The ones that sprout may mature or not. There may be hail, torrential rain, drought, late/early frost, birds, insects, or all of the above. But you plant anyway, and you tend, and you weed, and if you happen to be blessed with a combination of persistence, know-how, and sheer luck, you will reap something. It may not be exactly as you had hoped, but it will be a start.
Tomatoes, in my mind, are the epitome of this show of faith. Every year that I've grown tomatoes, some prohibitive force has prevented me from having a bumper crop. The first year, a long, cool, wet spring caused most of my seedlings to dampen off. The second year, poor soil and drought halted my harvest. This year, a combination of too much rain at the wrong time and hot, hot weather caused many of my tomatoes to crack and rot on the vine before they ripened.
However, there is some assurance to be had in the smaller tomato varieties. They mature faster, tend to bear more fruit, and are often very flavorful, as if to compensate for their smaller stature. This year, in addition to planting some heirloom varieties, I hedged my bets by planting a variety of golden cherry tomato called "Dr. Caroline."
These bright and utterly sweet tomatoes were the first to set fruit, the first to ripen, and my most prolific tomato. We ate most of them out of hand or in salsas and salads, but we had enough to put up one batch of Golden Cherry Tomato Ginger Jam. This recipe is directly from the Joy of Cooking and is truly a pleasure to look at and to eat. It is an almost glowing golden color. Set a jar of it on your windowsill to catch the light and you'll see what I mean.
This recipe is the yin to tomato jam's yang. I won't go so far as to say it's better; it's just a very different sort of tomato jam. More jammy and less ketchupy, bright and citrusy, and a good use for golden cherry tomatoes. It can be used like a jam--on toast. It can also be served alongside a stinky cheese or even as a topping for ice cream. The tomato flavor is there, but the marriage of sweet tomato, lemon, and ginger make for something that straddles the line between dessert and dinner.
Before you begin any canning recipe, sterilize your jars. Remove the lids and rings. Place the jars in a large pot with a rack in the bottom, cover with water, and bring to a boil. Boil for 10 minutes. Place the lids and rings in separate saucepans, cover them with water, and heat over medium. Do not boil the lids. Simply heat them.
I like to have a "canning station" set up to make things easier. I have my jars sterilized and sitting on a clean kitchen towel on the counter by the stove. My lids and rings are in separate saucepans, and I have a pair of tongs to remove them from the hot water as I need them. I also have a canning funnel, a jar lifter, and a ladle at the ready. A butter knife serves as a tool to remove air bubbles from the jars. As soon as the jars are filled, the pot of water I sterilized the jars in will serve as my water bath.
Wash and slice in half, reserving the juice:
2 pounds yellow or orange cherry or plum tomatoes
If using plum tomatoes, quarter them. Either way, combine in a bowl with:
2 cups sugar
Steep for 4 hours at room temperature, or refrigerate for up to 24 hours.
Peel and slice into thin strips:
4 ounces fresh ginger, washed
Place the steeped tomatoes and ginger in a large saucepan along with:
5 tablespoons bottled lemon juice
Finely grated zest of 2 lemons
Slowly bring the syrup to a boil, then boil rapidly until it thickens visibly and falls from a spoon in heavy drops (I call this a "bat wing"--instead of dripping from the spoon in a thin stream, the jam will start to fall from the spoon in sheets as it thickens). For this jam, I recommend boiling it until it is as thick as you want it rather than going by temperature alone. It should be syrupy and reduced considerably. If you like, put a few plates in the freezer and drop a small spoonful of jam on a cold plate. If the jam is still runny after sitting on the plate for a minute, keep boiling. If the jam sets up to your liking, you're done.
Ladle the jam into hot half pint jars, leaving 1/4-inch headspace. Place in your water bath, bring the water to a boil, and process for 10 minutes after the water has come to a boil. Remove from the water bath and let cool completely. You should hear little popping sounds as the jars seal. If, after 24 hours, all the jars have not sealed, you can re-process the unsealed jars or just place them in the refrigerator.