You can buy almost any food in a can, from pineapple slices to ravioli to Spam. While most canning that's done at home is with glass jars, not metal cans, the verb that describes the process remains "can." But language is dynamic, constantly evolving to keep pace with the changing meanings it conveys. And recently, I've noticed a new verb in circulation.
Overheard at a coffee shop: "Let's jar tomorrow after the farmers' market."
Via e-mail: "What are you jarring these days?"
At the farmers' market: "They jarred on their first date."
This linguistic revolt reveals some of the energy and creativity being focused on home economics these days, but how the jarring's done remains more important than what you call it. And given that harvest season is jarring season, it's time for me to crack open my jar of knowledge on the act itself.
This conversation carries liability concerns, because it's possible to get sick and even die from poorly jarred food—not the kind of jarring experience we want. So if I seem extra anal today, it's because I don't want anyone to get hurt, or sued.
The science of jarring recognizes two primary categories of contents: high-acid foods, like fruits or pickles, which are less susceptible to spoilage and low-acid foods, like veggies not pickled in vinegar solution, beans and meat, which carry a higher risk of spoilage.
High-acid foods can be jarred in a water bath, which is simply a pot of boiling water in which sealed jars of food are submerged. Any pot that holds enough water will suffice, but most people use a specialized five- or eight-gallon enameled kettle.
Low-acid foods have to be jarred in a specialized pressure cooker called a "pressure canner." Unlike the pressure cookers used for cooking, pressure canners have gauges that measure their interior pressure in pounds per square inch. Different foods have to be pressure-jarred for different amounts of time, and both time and pressure requirements increase with your elevation. Below 1,000 feet, 10 lbs. of pressure is standard for most foods. Add a pound for each thousand feet above 1,000. Also, add 10 minutes to the processing time if you're above 1,000 feet, and a minute more for each additional thousand feet. After processing your jars as directed by your recipe, turn off the heat and allow the pressure to drop to zero before opening the unit.
There are two parts to the jarring package, in addition to the jar itself: the lid, which contains a rubberized ring that seals against the rim of the jar, and the ring, which is screwed onto the jar's threaded neck, holding the lid in place. Jars and rings can be re-used, but lids should only be used once.
The jars have to be squeaky clean and free of cracks, with unblemished rims. It's best to use jars intended for jarring, aka Mason jars, like the Ball or Kerr brands, though many people reuse mayonnaise or pasta sauce jars. While canning rings and lids will fit many such jars, the glass from which they're made isn't necessarily up to the temperatures and pressures that jarring can produce. If these jars do survive jarring and the lids seal, then you got away with it, and the result will be the same as if you'd used Mason jars. But it's likely that some reused grocery jars will break in the process, turning the water bath or pressure cooker into a soupy sea of unpreserved, unrecoverable, wasted produce. Mason jars, though stronger, also can crack. To avoid this, keep the jars and their contents as warm as possible prior to lowering the jars slowly into the boiling water. A pair of "canning" tongs really helps in dealing with hot jars and boiling water.
Both lids and jars must be sterilized before use. The jars can be boiled, steamed or baked at 220 degrees. Sterilize lids in a pot of water, bringing the water to the pre-boiling point where little bubbles start to float up, then removing the heat before the water boils. Leave sterilized lids in the hot water, covered, until use.
Once your jars are sterilized and ready for filling, a common rookie mistake is to overpack them. The term "headspace" refers to the empty space between the top of the food and lid. If you don't leave enough headspace, there won't be enough air to contract as the jar cools, and the lid might not seal. Not all "canning" recipes specify headspace, so my rule of thumb is to not let anything stick above the point where the rounded glass of the jar joins the vertical, threaded neck, leaving a good inch of headspace.
After removing the finished jars from the pressure cooker or water bath, set them aside and allow to cool. If you did it right, you'll be serenaded by a chorus of pings as your jars seal, one by one.
Store your sealed, labeled and dated jars in a cool place and inspect each jar before and after opening. Look for bulging lids, discolored contents, contents that bubble upon opening, escaping gas upon opening, and off odors. The jar's contents should be tossed at any suspicious sign.
While you may end up tossing some innocents, playing it safe will keep you going for many jarring years to come.
Ask Ari: Snake bitten
I received lots of feedback about last week’s rattlesnake column. Two examples:
Your dish sounds great, but I’m hoping you’ll learn to catch the buggers, put them in a bucket and take them elsewhere. Rattlesnakes do a great job on rodents. I’d rather get a snake bite than Hanta. Geez!
The rattlesnake that my cats had cornered for an hour just fled as quickly as possible when I removed the cats. It never showed its face again. Then there were two in my boathouse years later that politely rattled to let me know they were there one dark night. My husband removed them with a snake rope he made with plastic pipe and a rope noose or loop going through it. He put them in a bucket and hauled them off. Come on! Get brave!
And another, also not really a question:
That picture of you in the short shorts was jarring. It touched nerves.
Okay, so I made two major mistakes. But the question is which offense is worse, wearing those short shorts in public or killing a mouse-killing snake? If anyone responds to this question I’ll post the results on my blog at www.flashinthepan.net.
Since my inbox was otherwise pretty empty this week, I’ll end with a plug for a super cool calendar put together by the Missoula Community Food and Agriculture Coalition (CFAC). It’s called “Capturing Missoula’s Foodshed,” and includes lots of cool photos of farms, food, chickens, etc., as well as some recipes, including one by me. Call 880-0543 or visit the UM Book Store or the Good Food Store to secure your 2010 calendar. It costs $15, and proceeds benefit CFAC.