Vickie Belknap, an Oregon State University master food preserver, examines a pressure-canned jar of mixed vegetables at the Jackson County Fair. - Bob Pennell illustration

Under Pressure

A severe scar marring the face of a grade-school classmate warned Vickie Belknap off pressure-canning for decades.

It wasn't until Belknap's family moved to the Rogue Valley, where her father caught his first salmon, that Belknap bought a pressure-canner.

"It's so much better than what you can buy in the store," Belknap said, referring to home-canned fish.

Home cooks who want high-quality preserved foods have long employed pressure-canning, despite widespread belief that the procedure is risky. But given the right equipment and instructions, pressure-canning requires no other expertise, said Belknap, an Oregon State University master food preserver. A Tuesday class will demystify the process.

"It's to take the pressure off pressure-canning," Belknap said.

The U.S. Department of Agriculture in 1917 deemed pressure-canning the only safe method to preserve low-acid foods without the risk of food poisoning. Home canning gained importance during World War II as families across the country tended victory gardens.

Following a post-war heyday when poor-quality models were common, pressure-canners were extensively redesigned with safety features. Today, pressure canning remains the only way to render low-acid foods — vegetables, meat, poultry, fish and seafood — shelf-stable.

"It gives you a wider variety of foods — things that tend to be hearty," Belknap said.

Yet jams, jellies, salsas and pickles far outnumbered pressure-canned foods at last week's Jackson County Fair. Each of those products can be safely canned in a boiling water bath.

"Most people stay with water-bath canning because it's the easiest," Belknap said.

Those ranks included a 60-year-old man, Belknap said, who told her he boiled canned meat in a water-bath for three hours, yielding delicious results.

"And I said, 'That's very dangerous,'" Belknap said, adding that children and the elderly are particularly susceptible to botulism that could grow in such situations.

Pressure-canning kills botulism spores by exposing food to a temperature of 240 F for 20 to 110 minutes, the time depending on a jar's contents. Pressure inside the kettle, which varies according to altitude, helps food attain the critical temperature. (Correction: See below.)

If the science sounds simple enough, experts like Belknap preach an all-important caution: Always use a current canning book because safe cooking times and reliable recipes continue to evolve.

"We've got more hybridized vegetables; we've got more pollutants in the water," Belknap said.

"There's a lot of pathogens out there, and it's getting worse."

Extension offices like Oregon State University's center in Central Point carry the most current volumes for just a dollar or so apiece. Tuesday's Extension class also offers an opportunity to test pressure-canners' dial gauges, which should be checked yearly.

Reach reporter Sarah Lemon at 776-4487, or e-mail

Correction: The time needed to kill botulism-causing bacteria originally was listed incorrectly in this story. The version that appears here has been corrected.

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