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Shawn 07-29-2002 03:25 AM

Canning Basics
Canning is quite a bit different from ordinary cooking. When you cook, you can follow a recipe. Or, you can be adventuresome and add or leave out ingredients as you see fit. Maybe today you're feeling extra "garlic-y." Or, perhaps you'd like to toss a handful of nuts into that banana bread. Go right ahead, no problem.

But when you're canning, experimentation can be downright dangerous. Time and temperatures have been worked out very carefully and must be followed to the letter. Too little time or too low a temperature means you're not protecting the food against bacteria, enzymes, molds, and yeasts. Too much time or too high temperatures can result in needlessly destroying nutrients in the food and damaging its taste.

So, always follow directions and recipes precisely. Don't improvise, compromise or try to be creative. Botulism and other food poisoning is very serious. Be sure to protect yourself and your family while you enjoy fresh, wholesome canned food. Play it safe and take all the proper precautions. Remember, canning is like anything else: It gets easier every time!

Important Checklist

Make sure you're totally ready to get started by following a few simple preparations:

INSPECT YOUR JARS. All jars should be free of cracks or nicks in the rims. If any are damaged, don't use them because they can cause food to spoil. Also, be sure you have enough jars for the task at hand.

CHECK JAR TOPS. If you're using the two-piece vacuum caps and lids, make sure you have enough, that they're all new and rust-free, and that the screw bands are also rust-free. Make similar checks with other types of lids.

USE COMPLETELY CLEAN EQUIPMENT. If you're pressure canning, check the gauge on your pressure canner to be sure it's functioning properly.

WASH AND RINSE JARS THOROUGHLY. Use dish detergent, rinse well. Set jars in clean, hot water until used. If using dishwasher, keep jars in dishwasher until ready to use.

MAKE SURE LIDS AND BANDS ARE CLEAN. Follow manufacturer's instructions. Zinc caps should be boiled for at least 15 minutes, washed with detergent, then rinsed and kept in hot water until used. Glass lids used with jars with wire bails should be prepared the same way.

REMOVE BLEMISHES FROM PRODUCE. Cut out any dark spots, whatever is discolored or doesn't look right and fresh.

SCRUB PRODUCE. Thoroughly wash and rinse produce.

HAVE ENOUGH ROOM TO WORK. Crowding can cause spillage, breakage, etc.

Everything checked out, clean and fresh? Now you're ready to begin.

Is Canning Safe? -- YES

If you follow these directions carefully, there's no reason to fear the results.

Canning was risky back in Grandma's day. She used old containers, rubber rings that often didn't seal properly, and did it all in a big boiler, just as her mother had taught her.

Today, equipment is far better. More important, commercial firms and the U.S. Department of Agriculture have joined in studies of canning safety. All the methods have been tested, retested, and tested again. Grandma's ways have been discarded in favor of methods that are easier, quicker, far, far safer, and that preserve more of the goodness of the fruits and vegetables.

Shawn 07-29-2002 03:29 AM

When you cook, you follow a recipe—maybe. You adjust it, very often, to your own tastes or those of your family. You leave out that much garlic in the stew, add nuts to that whole wheat bread recipe. You change the ingredients a bit, to make the recipe truly yours.

You can't do this when you're canning. Experimenting can be dangerous. Time and temperatures have been worked out very carefully for canning. Too little time or too low a temperature means you're not protecting the food against bacteria, enzymes, molds, and yeasts. Too much time or too high temperatures may mean you're needlessly destroying nutrients in the food and damaging its taste. Be fussy in following the directions to the letter.

First, a few basics so you'll understand the why's of canning.

Two Methods:

All foods are canned by one of two methods:

Boiling water bath method. This is used for acid foods. These include all fruits, tomatoes, sauerkraut and most foods to which vinegar has been added, such as most pickles and relishes.
Steam pressure canner method. Used for foods containing little acid. These include vegetables, except for tomatoes, and meats, seafood, and mixes of food that include some low-acid foods.
All foods, acid and non-acid, contain enzymes and can harbor molds and yeasts, all of which will cause food to spoil. All of these can be inactivated or killed by the heat of the boiling water bath canning method.

The steam pressure canner method is used to destroy another threat against canned food—bacteria and their by-products. These include Salmonella, Staphylococcus aureus, and Clostridium botulinum, the cause of botulism.

Since these harmful bacteria are not a problem in the high-acid foods, there's no reason to use this high temperature method with them. These bacteria will thrive in the low-acid foods and aren't destroyed by the 212°F temperature of the boiling water bath method, but succumb to a recommended period of 240°F heat. So the steam pressure canner method must be used for them.

Two More Terms--

Two other terms used in canning should be explained. They refer to packing the jars—putting food in them as an early step in canning.

Raw Pack or Cold Pack: These terms, used interchangeably, refer to putting uncooked food into a jar to which a hot liquid is added.

Hot Pack: This refers to putting into jars for processing food that has been cooked to some degree. Hot pack sometimes requires less processing time, since the food already is partially cooked. Sometimes it takes as long, or longer, because of the denser pack.

Instructions for each food will explain which of these packing methods should be used and the processing time required.

Your First Time?
If this is your first attempt at canning, here are some hints that should make it easier for you:

Start small. Six quarts of tomatoes or a half-dozen jars of jam or jelly are plenty for this first try.

Be prepared with everything you need. Jars and fresh lids. All the equipment—and that includes a pressure canner with a gauge that's been tested, if you're pressure-canning. Most important, produce that's at the peak of perfection, ripe but not too ripe.

Have a large cleared area to work in. Canning takes lots of space.

Have more time than you'll need. You figure you should have it done in an hour? Then give yourself two hours and feel no pressure.

And realize that canning is a lot like many other kitchen tasks, baking bread or following a complicated recipe—it gets a lot easier the second time you do it.


Here are two rules regarding equipment:

Make certain equipment is in good condition. A pressure canner with a faulty gauge or jars with nicked edges can cause food to spoil.

Make certain equipment is available. Lay it all out in the kitchen before you start. Mid-point in a canning session is not the time to remember you forgot to buy those canning lids.


You'll need a pressure canner if you can vegetables (except for tomatoes, sauerkraut, and pickles), plus a kettle with a cover if you're canning fruits using the boiling water bath method.

Pressure canners are manufactured in various sizes: match your canner with your canning ambitions; and if you'll be doing a lot of canning, buy a big canner and save both time and heating costs with it. When using a pressure canner, follow the manufacturer's instructions. All canners require a rack on the bottom, so boiling water or steam can circulate under the jars.

The dial-type pressure canner has a gauge that shows the pressure, a pet**** that allows steam to escape under a controlled pressure, and a safety valve that will pop and thus relieve pressure if the pet**** becomes stuck. The gauge must be checked for accuracy each year.

The weighted-gauge pressure canner has a one-piece, metal weight-type pressure control. When the called-for pressure is reached, you will hear the control jiggle, releasing steam and preventing the pressure from rising higher.

A kettle with a cover is used for boiling water bath canning of high-acid foods. Most people use a conventional black enamel canner. It is resistant to acids and salt solutions, and so can double for cooking pickles or brining vegetables. The kettle must be deep enough so that jars sitting on a rack will be covered with at least an inch of water. There must be at least another inch in the kettle for the space required for a rolling boil.

Capacities of Canners

Jars and Lids

Jars are sold in sizes from a half-pint to a half-gallon, and with a variety of lids. Most popular are the pint and quart sizes with the two-piece vacuum-seal lid held in place during processing by a metal band. With these lids, it's easy to tell when the seal is perfect. The lid makes a definite snapping click when it seals while cooling. The lid curves downward when sealed and remains so. When tapped with a spoon, the sealed lid rings clear.

A Variety of Jars -- Other Equipment

You probably have many of the items you'll need. These include knives, long-handled spoons, saucepans, measuring cups, a colander, and scrapers. These are additional helpful aids:

The jar lifter is used for removing jars from the canner. Use one and you won't burn your hands.

The jar funnel with its wide mouth makes it easy to fill jars without getting the food on the rim of the jars.

A bubble freer is handy, cheap, and makes it easy to get bubbles out of the food before processing.

For a timer, look for a photographer's timer. It's accurate, and will tell you with a loud ring when time's up.

A Variety of Jars

Here are three of the most common canning jars found today.

If you're buying jars, we recommend pint or quart jars with the two-piece vacuum lid. The underside of the lid has a strip of rubberlike sealing compound on the edge, where it comes in contact with the rim of the jar. A metal screw band holds the lid in place during processing, and is removed when the jar has cooled and the vacuum inside the jar holds the lid. These lids are discarded after one use; the bands are saved.

The older style jars that have caps with porcelain liners are sealed by placing a wet rubber ring over the neck of each jar. The cap is screwed on firmly, then backed off a quarter-inch to allow air to escape during processing. After processing, but while the jar is still hot, tighten the cap to complete the seal. Careful—it will be hot. Use potholders or oven mitts. When the jars are cool, test the seal by tipping them. Any leakage indicates the jar is not sealed.

The jars with wire bails and glass lids are still in use, although they haven't been manufactured for many years. A wet rubber ring is fitted over the neck so that it rests on the glass ledge of the jar. The glass lid is placed so that it rests on the ring. The long wire bail is set in place in the groove on the top of the lid, and the second bail is left in the up position. After processing, and while the jar is still hot, you should push the second bail down against the side of the jar. When the jars are cool, test the seal by tilting each jar.

When using any of these jars, do not attempt to open them to replace any liquid lost during processing.

Shawn 07-29-2002 03:33 AM

The fruits and vegetables you can should be prize winners, at the very peak of perfection, and certainly not too ripe. They shouldn't be blemished or bruised. Whether they are from your garden, a grocery store, or produce market, they should be fresh. Ideally, you will both pick or buy and can on the same day. If that's impossible, the produce should be refrigerated.

It must be clean. Washed carefully and completely, the produce must then be pared or cut up with clean knives.

Here are some suggestions on a few of the vegetables and fruits you may be canning:

Beets: Usually best when no more than two to three inches in diameter. Some varieties stay tender and flavorful when larger and can easily be canned.

Lima Beans: Best when pods are well-filled and the seed is firm but not hard.

Snap Beans: Harvest when so crisp that they snap readily.

Greens: Use young, tender leaves of mustard, spinach, kale, and collard greens. Kale is better if harvested after a frost.

Peas: Pick as soon as they are mature enough to be shelled.

Tomatoes: Select tomatoes that are firm and ripe but not overripe. They should be free of bruises, spots, decay, molds, cracks, and growths. Otherwise, tomatoes may be low in acid—too low for safe canning.

Apples: If canning slices, remember that green apples, with seeds not yet brown, will produce hard, sour slices, while overripe fruit will be mushy, looking much like applesauce. The best applesauce is made by blending two or more relatively tart cooking-type apple varieties. Green apples make sour sauce; overripe apples make a watery, bland sauce.

Bramble Berries: Harvest blackberries, raspberries, dewberries, and similar fruits in shallow trays or pans, to avoid crushing the berries. Can the day of picking. If that's impossible, quickly cool the berries to 33°-35° and hold overnight at that temperature.

Cherries: Pick when red-ripe, sound, and not oversoft. Hold at 33°-35° temperature if canning is delayed more than four hours after picking.

Pears: Unlike most fruits, pears shouldn't be ripened on the tree. If they are, they begin to rot inside, and will quickly spoil. Pick when full-sized, mature green, and when they can be picked easily from the tree. Pick and handle carefully, to avoid bruises, since damaged fruit will spoil quickly. Store until ripe in a cool place that's free of odors. This may take a few days or weeks, depending on the variety.

Plums: They should be tree-ripened for best flavor, with deep color and a powdery bloom. Can quickly, if possible, since they become mushy very rapidly.


Yield from Fresh Vegetables and Fruits. The number of quarts of canned food you get from a given amount of fresh vegetables and fruits depends on quality, condition, maturity, and variety, as well as the size of the pieces and how the fruit or vegetable is packed. Generally, the following amounts make one quart of canned food:

food (on top) & Pounds (underneath)

2 1/2 to 4 1/2
Beans, lima, in pods
3 to 5
Beans, snap
1 1/2 to 2 1/2
Beets, without tops
2 to 3 1/2
Carrots, without tops
2 to 3
Corn, sweet, in husks
3 to 6
1 1/2
Peas, green, in pods
3 to 6
Pumpkin or winter squash
1 1/2 to 3
Spinach and other greens
2 to 6
Squash, summer
2 to 4
Sweet potatoes
2 to 3

2 1/2 to 3
2 1/2 to 3 1/2
2 to 2 1/2
1 1/2 to 3
2 to 2 1/2
2 to 3
2 to 3
1 1/2 to 2 1/2

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