Saturday, September 11, 2010

First batch of tomatoes for the year

Riverdog Farm, from whom we get our weekly vegetable box, offers bulk veggies too. In particular, they have an amazing deal on Early Girl and Roma tomatoes: 20 lb for $25. (These tomatoes go for $3/lb at the market.)

In order to be well-stocked until April or May, we expect to can about seventy pounds of tomatoes, all together, and while they're fresh eat another ten pounds at least. So for four weeks this month, we'll be canning tomatoes, seventeen or eighteen pounds at a time. This week, we filled eleven quart jars.

Get the canner heating up on two burners. On a burner in the back, keep the tea kettle ready in case you ever need more boiling water. On your last burner, bring a medium pot of water to a boil. Also prepare an ice bath in a large pot.

While waiting for things to come to a boil, make sure your jars are clean, and add 1 teaspoon salt and 2 Tablespoons lemon juice to each quart jar. If you like, add also some strongly flavored herbs to the bottom: whole peeled garlic cloves, bay leaf, etc.

Working half a dozen at a time, drop whole clean tomatoes into the pot of boiling water. Wait ninety seconds and remove them with a slotted spoon, plunging the tomatoes immediately into the ice water. After about thirty to sixty seconds, you should be able to handle the tomatoes without difficulty, and the skins should slough right off. It's important to peel tomatoes before canning, because the skins turn very tough when cooked. Remove the tough part right around the stems, halve the larger tomatoes, and pack the jars, trying to squeeze as much tomato into the jars as possible.

Bring that tea kettle back the a boil, and pour boiling water into the packed jars to fill them up, leaving half an inch of headspace at the top. Tap the jars on the counter a little to dislodge any air bubbles. Add clean, unused lids, and screw the rings on only very loosely: they're there just to keep the lids in place while canning, but you want air to be able to escape.

Boil the jars fully submerged in the water for forty five minutes. This will cook and sanitize the tomatoes (boiling is at 212°, sanitizing is about 180° for five minutes, so you're just trying to heat the jars through, really). It also makes the air in the jars expand and escape. The rings have a wax coating on them, so once the air leaves, they attach down. Then, after you remove the jars, air can't get back in, and there's enough pressure to keep the jars closed, even without the rings. After canning, let the jars cool twenty four hours, and then test all the seals. Those that don't seal you should keep in the refrigerator and use within a few weeks. Those that do can sit on the shelf for about a year, and should be refrigerated after opening.

(Botulism bacteria, which creates a lethal toxin, can survive boiling, although dies at boiling after about ten hours. But it cannot grow in high oxygen environments, which is why it doesn't hurt us usually, although its spores are everywhere, and more importantly, it can't grow in acidic environments, which is why you added the lemon juice (tomatoes are almost but not quite acidic enough on their own). Nevertheless, never eat an exploded can. Don't even touch it. Wear gloves to move it into a plastic bag, seal the bag, then put another bag over it, and tie it off, and bleach the kitchen, and don't let animals get access to the spoiled food, even at the dump. Botox should be treated as hazardous waste. But it is very rare that this is ever a problem; just take basic precautions and you're fine.)

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