Then a few potted tomato plants in the backyard taught me how much heat they need to mature. Once they started to fruit, the woman next door was in awe, as not thirty feet away she had tried to grow tomatoes to no avail. We decided it was the exposed, south-facing cement wall behind my plants, storing heat during the day to pass to the tomatoes at night, that let them flourish. After harvest, I built a special room in my heart for tomatoes, the demanding plants that grow best in greenhouses and small anomalous corners of backyards. They are a luxury, and the crown of the late-summer harvest.
In Edmonton, it’s hard to acquire the amount of tomatoes that necessitates preserving. However, for several years my mom has been taking advantage of a boom and bust greenhouse production cycle. She buys from a greenhouse that only produces in summer months, so come September they have a windfall of beautiful tomatoes that are dirt cheap. She’s able to buy 40 lbs of romas for $20.
I keep expecting preserving to compromise the eating-quality of fresh ingredients. But, as with other preserves like jam and pickles, I’m left with a fantastic pantry item with an intense, focused flavour. In fact, I think I enjoy oven-dried tomatoes more than fresh ones. People feel compelled to specify that they are oven-dried because of the popularity of the brilliantly marketed sun-dried tomatoes. However you dry them, the process evaporates moisture to concentrate flavour and acidity, and gently caramelizes some of the sugars. These tomatoes are dynamite in pasta or tapenade, or just on a plate with garlic sausage.
Cut the romas in half and remove the juice and seeds. Strain this mixture and reserve the juice, either to drink or to use in canning (see below). Toss the flesh of the romas in oil, salt, and pepper. Go easy on the seasoning, as the tomatoes will reduce to a fraction of there original mass. Place the tomatoes on a sheet pan lined with parchment or silicon, and put them in an oven on low heat, maybe 200°F. Not trusting the thermostat in my oven, I have a high-temperature thermometer clipped to the oven rack. I have to set my dial below 150°F to achieve 200°F. Leave the tomatoes for several hours, until they develop a dense, chewy texture. This year mine took about twenty hours. Packed in oil they will keep for months.
Authorities like Bernardin and the USDA say that the pH of tomatoes is on the cusp of acceptable acidity for canning. As such they recommend the addition of lemon juice to the canning liquid, about two tablespoons per quart. From a flavour standpoint, this makes me cringe. I have, however, read testimonies of people who grew up on tomatoes canned without any acid supplements.
I wonder if, since the pH walks the line of food safety, I could give it a bump in the right direction by slightly reducing the tomato juice we can with. Some water boils off, leaving a higher concentration of acidity.
As this was my first year canning tomatoes, I tried a bunch of different recipes. All started by blanching, shocking, and peeling the tomatoes. Then I canned some in water, some in tomato juice, some with lemon, some without, some with herbs and salt, some without.