Everyone's heard them - the horror stories of someone's pressure canner being pushed to the max and exploding in the kitchen.

And while nobody likes to try a cooking experiment that may cause bodily injury, there's really no need to worry when it comes to canning. If you're following the directions and keeping an eye on your pressure gauge, the process of canning can be a rewarding - and pain-free - experience.

As gardens across Northeast Georgia wind down from summer, canning, or processing, is one way to continue to enjoy your garden's food - or, fresh produce from a local farmers market - throughout the rest of the year.

Know your food

The basis of all canning methods lies in what it is you're trying to preserve. Specifically, foods are classified as either low-acid or high-acid foods, and your canning method depends on knowing what you're starting with. Foods that are low in acids require a steam pressure canner and need to be processed at 240 F. On the other hand, foods high in acids only require processing in a boiling water bath, at 212 F, since the acids in the food naturally kill much of the harmful bacteria.

Low-acid foods are generally all vegetables, and include okra, carrots, turnips, beets, beans, greens, asparagus, peas, corn and hominy, according to the Ball Blue Book Guide to Home Canning and Freezing.

High-acid foods are generally fruits, and include plums, berries, prunes, apricots, apples, blackberries, cherries, peaches, kraut, pears and tomatoes (which are, technically, a fruit).

Judy Harrison, a professor in foods and nutrition and an extension food safety specialist with the National Center for Home Food Preservation at the University of Georgia, said one of the most common mistakes people make when they're canning food is not taking into consideration this rule about acids and bases.

Often, she said, she will get calls from home canners who have an array of ingredients laid out and ask for a recipe and processing time for what they have in front of them. But this isn't the way to go about canning, she said.

"I guess the biggest misconception is that you can mix anything together in your own recipe and you can put it in a jar and can it," she said. "It's one thing to
add a dash of hot sauce to a jar of preprocessed pickles, she said, but deciding to chop up some green tomatoes and onion changes the recipe entirely.

"We run into this a lot with salsa," Harrison said. "What you end up with is a mixture where you really don't know if the amount of acid you're adding to it is going to be safe enough to can in a water-bath canner."

Bottom line is, know the type of food you're going to process before starting, and stick with a recipe you know has been used before and proven to work.

The process of processing

Unless you're heading out to a local cannery, home canners will need a pressure cooker of some kind in order to achieve the high temperature needed to cook low-acid foods. Harrison said these come with two types of pressure gauges on them - a gauge that shows the actual pressure, which needs to be checked once a year before starting to process food, and a gauge that rocks back and forth when the correct pressure is reached. These do not need to be checked for accuracy, but it is important they are clear of debris before starting the process.

Once the food is in the canning jars, it's simply a matter of adding some water to the pressure cooker, tightening the lid and adding heat. Once the gauge shows you've reached the correct pressure inside the cooker, you follow the cooking directions on your recipe for the cooking time.

During this process, the pressure cooker sputters and whines. Some of them may drip water, while others might just rattle a bit. But don't be concerned; as long as you followed the instructions on your pressure cooker and added the correct amount of water - and, once the correct pressure is reached, you turn the heat down slightly to maintain that pressure - nothing will explode.

Once the cooking time has elapsed, you let the cans sit in the cooker until the pressure comes down. Then, gently lift the jars out of the pot and let them rest overnight on a cloth or wooden surface.

While sitting, the jars will form their seal, but every so often one top won't. When you press on the tops of the jars, they should be concave, and if it pops back at you, the seal didn't take. These need to be reprocessed with a new lid or used immediately.

Harrison said there are a few reasons why the seal sometimes won't work.

"It can be just something as simple as you didn't tighten that jar lid down as much as you did the others, so that could cause it to not seal. Sometimes if you have particles trapped in the sealing surface, that might cause it to not seal. Sometimes you can have, if the jar happened to be nicked at the top ... that can cause the jar not to seal," she said. "The other thing it can be, you might actually have a defective lid.

"You use a new lid every time. ... every year you should buy new lids and if you have lids that are left over it's a good idea to buy new ones every year so that sealing compound is fresh and not dried out. And only use them once."

A growing trend

At the Stephens County Cannery last week, South Carolina resident Barbara Yoder and her daughter were busy processing nine bushels of fresh-picked apples to make applesauce. Yoder said she comes to the cannery a few times a year to process food, sometimes it's with other family members and sometimes it's with her church group, where they make jars of food for their food bank.

But Yoder said she doesn't mind making the nearly half-hour drive from her home in order to put up some vegetables for the winter. And, Harrison said, Yoder is part of a trend she's seen in more people canning across the country.

It doesn't matter your age or experience, Harrison said she's seen an increase in phone calls about canning from all over the country.

"We have noticed that there seems to be more people canning this year, like an upsurge of it this year ... Pretty much nationally there seems to be more people that are calling and wanting more information about canning," Harrison said. "That could be one of two things. First of all, we've had more rain this year than we've had in the past two or three years, so it could be people are having better luck with their garden this year. And another thing is, I think there's a bigger interest in preserving your own food because people are starting to purchase foods at farmers markets, more access to locally-grown products, and I think that may be contributing to that as well."

Plus, there is a social aspect to canning, too, according to both Yoder and Reggie Stowers, an agriculture teacher at Dawson County High School who also runs the Dawson County Cannery. They had more than 500 unique visitors to the cannery since July, and he said each processing is a chance to meet someone new and help them out.

"Everybody helps everybody; it's a real community-type activity," Stowers said. "It's a real neat process, the way that it all happens because everybody helps everybody."