A Guide to Food Canning and Freezing

Sandra in Gardening 26/04/2014

Freezing and canning are wonderful ways to preserve the bounty of your garden, local market, and/or even sales at your grocery store. If you’ve never preserved food before, it may seem a bit overwhelming. Maybe you’ve dabbled a bit in canning or freezing (most of us freeze foods at one time or another!), but you’ve never made a habit of it or attempted to feed your family on preserved foods through the winter. Regardless of where you are in the food preservation experience, a basic guide can be very helpful.

What Foods to Preserve

What Foods Work Best for Canning?

When it comes to preserving foods, canning is what most people think of. Canning is a time-honored way to preserve the harvest, even though it’s actually pretty modern (true canning didn’t begin until the 1800s).

It may surprise you to find out what foods that you can actually can. Here is a basic list of food staples that work best for canning.

Carrots

Another low-acid food, carrots are best canned using a pressure canner. Carrots can be packed in jars sliced, chopped, or even whole (especially if small). They can be steamed first or packed raw.

Citrus Fruits

Grapefruits, oranges, and tangerines are high-acid foods, so a boiling water bath will probably be fine. Raw segments can be placed in jars and sugar syrup poured over, leaving an inch and a quarter at the top.

Corn

Canned corn can last a long time and bring the taste of summer into the middle of winter. Use a pressure canner to kill bacteria, as corn does not have a lot of natural acidity. You can pack it raw and add salt if you like, then fill with purified water to 1 1/4 inches from the top.

There are also many other foods that can be canned successfully, from berries to apples to cucumbers.

What Foods Work Best for Freezing?

Some people choose freezing because it is said to preserve nutrients and freshness; others prefer freezing because it seems less complicated than canning. But you might be wondering what foods freeze well. Can you freeze fresh fruits and vegetables? Are there some foods that get ruined by freezing?
Here are some suggestions as to what foods are good for freezing.

Tomatoes

Did you know you can freeze tomatoes? You can! Here are some tips on freezing these fruits.

Freeze them whole, unpeeled. Just core the tomatoes and freeze them whole on a cookie sheet. When they are frozen, put them in a zip top plastic freezer bag. When you thaw them to use them, the skin will slide off easily. You can also peel them first if you prefer.
Cook them first. Cut washed tomatoes into quarters (cutting out the core if necessary), simmer them in their own juice in a covered saucepan until they are soft (just a few minutes), and allow to cool. Then you can freeze them in freezer-safe jars or zip top freezer bags.

Cabbage

Cabbage freezes well, which surprises some people. Simply cut cabbage in wedges or shred it, and freeze in zip top bags. Draw the air out of the bags by leaving a half inch or so unzipped, inserting a straw, sucking the air out and quickly sealing the final half inch.

Bell Peppers

Slice or dice washed bell peppers, removing the seeds and stem. Place the cut peppers on a wax paper-covered cookie sheet and freeze. Once frozen, you can put them in a zip top bag.

Green Beans

Washed green beans freeze very well. Snap or cut off the ends, cut to desired length or leave whole, and blanch them for 3 minutes in boiling water. Plunge them into ice water to end cooking, drain, and freeze in plastic bags.

Apples

Yes, you can freeze apples! The best way to prevent them from browning is to place washed apple slices in a freezer-safe, 2-cup glass jar, and then pour in 1/3 to 1/2 cup of filtered or purified water over the slices to fill in the space between the slices. Leave an inch of space at the top for the water to expand when freezing.

Berries

Freeze raspberries, blueberries, strawberries, etc. by placing washed fruit on a wax paper-covered cookie sheet. When frozen, you can put them in zip top freezer bags. You can also mash or puree berries and freeze the mash/puree in jars.

Peaches

Wash and slice peaches and freeze them the same way as berries – on a wax paper-covered cookie sheet, then a plastic bag. You don’t need to peel them first.

Fresh Herbs

Simply slip clean, fresh sprigs into a zip top bag, draw out the air, zip, and freeze.

Canning Methods for Various Foods

There are all kinds of methods and recipes for canning foods. But which method works best with which food? This is a rather important consideration, because incorrect methods can result in spoilage, unsafe foods, and/or wasted time and money. Here is a sampling of canning methods for various foods.

Pressure Canning

Your great-grandparents didn’t use pressure canners, you may be thinking. Why should you? Well, we’ve learned a lot about microbes and food spoilage since our great-grandparents’ day. One of the things we’ve learned is that you need really high temperatures for a certain amount of time to kill bacteria, especially if those foods are low-acid. High-acid foods are less hospitable to bacteria, so not quite as high a temperature is needed to prevent bacteria from growing.

Foods that should be canned using a pressure canner include:

Asparagus
Corn
otatoes
Carrots
Cabbage
Spinach
Kale
Green beans
Peas
Beans (such as pinto or kidney)
Apples
Pears

These are just some of the low-acid foods for which you’ll need a pressure canner.

Hot Water Bath

Some foods do fine in a hot water bath, that is, placing the filled jars in a deep kettle, pouring in water, and simmering it for 10 minutes or so (canning recipes give exact times). This works okay for high-acid foods, such as the following:

Berries
Tomatoes
Citrus fruits
Pineapple
Cucumber pickles (the vinegar in the recipe makes the food very acidic)

Freezer Canning

This is one of the fastest ways to preserve foods in freezer-safe jars. You can put the whole food into the jar, pour sugar syrup, broth or water around it, and freeze. You can also puree the food, cook it down into a sauce or jam, and freeze it that way. Make sure you leave a good inch and a quarter of air space between the food and the top of the jar. Here are some foods that work well with the freezer canning method:

Berries
Strawberries
Citrus fruits
Tomatoes
Corn
Homemade salsa

Vinegars and Oils

While it isn’t canning in the strictest sense, vinegars and oils are a great way to preserve herbs and spices. You pour oil or vinegar around lightly packed foods such as these:

Raspberries (vinegar)
Herbs such as basil, sage, mint, lemon balm and rosemary (vinegar)
Garlic (oil or vinegar)

Sauces

Surplus apples, pears, and tomatoes can be made into sauces like salsa, spaghetti sauce, straight tomato sauce, and apple/pear sauce. Follow your favorite recipe for making the sauce of your choice, then freeze, pressure can, or place in a hot water bath.

Canning and Freezing Equipment

Canning and freezing are not necessarily hard, but there are some particular pieces of equipment that you need. This equipment ranges from essential to optional, and some equipment is used in both freezing and canning. Here is a list of some of the basic equipment needed for canning and freezing.

Freezing

Freezing foods is considered simpler than canning (it is perhaps quicker), and some equipment is the same as canning. Some things are only used in freezing.

Cookie sheets You’ll need cookie sheets for a couple of things. First, cookie sheets provide a flat surface for freezing small foods like berries or foods chopped/sliced in pieces (like peaches and bell peppers). Once frozen, you can remove the food and place it in a bag. The other use for cookie sheets is as a flat surface on which to place soft plastic bags full of food you want to freeze. Without the sheet or tray, the bags bulge down between the bars of the freezer shelf and freeze to it.
Wax paper To prevent sticking, wax paper should be used to line the cookie sheets before freezing foods on the sheet.
Zip top plastic bags These are really handy for freezing non-liquid foods like berries, chopped vegetables, and herbs. Get the freezer bags as they are stronger and thicker than just zip top storage bags.
Glass jars As with canning, glass Mason jars can be great for freezing. You simply add the food to the jar and add liquid to fill in the space (or no liquid, depending on the food), and leave 1 1/4 to 1 1/2 inches from the top to allow for expansion.
Case freezer You can freeze food in any freezer, but if you have a large quantity that you’re going to be dipping into all winter, a case freezer (or just a separate upright freezer in your garage) can be very helpful. Also, case freezers go to a lower temperature than freezers attached to refrigerators, making food last longer and killing more microbes.

Canning

There’s no doubt that some special equipment is needed for canning.

Canning jars The glass canning Mason jars are best. You can get them in quart or pint sizes, and wide-mouth is usually preferred. You can even get them in 1-cup size.
Pressure canner For low-acid foods, a pressure canner helps remove any doubt as to the sanitation of the food. Pressure canners go to a higher temperature than boiling in a hot water bath, so more germs are killed.
Rubber-tipped tongs If you’ve ever tried to lift a hot jar from a pressure canner, you’ll know why you need tongs. Rubber-tipped ones help you grip the jar to get it out.
Wide-mouth funnel Pouring liquids into a jar (even a wide-mouthed one) can get messy without a funnel. Consider the wide-mouthed type to help you get the food into the jar with minimal mess.

Equipment Tips

Sterilization is essential. Everything – jars, tongs, lids, etc. – should be boiled for 10 minutes before use.
Low-acid foods need to be pressure-canned to make sure all bacteria are gone.
When freezing plastic bags, place them on a tray so that the bag does not sag between the rungs of the freezer shelf.

When to Preserve

Pretty much any produce can be preserved by canning and/or freezing. While the fresher the better, you don’t have to have a garden. You can preserve foods from your local farmers’ market and grocery store too. It’s a great way to take advantage of sales, but beware – sometimes great deals on produce mean the produce is on the verge of decay. That kind of sale produce is best eaten that same day. But if there’s a sale on fresh produce, go for it.

Toward the end of the growing season, you may find some great sales at your local farmers’ market or open air market. Bell peppers and tomatoes may still be picked fresh and ripe at the end of September, but the vendors are wrapping things up for the summer and will often have good deals.

Learning what foods are in season is a good way to find not only the freshest foods that will be available, but also to anticipate sales. If you know that peaches are in season from June to August, for instance, then you can keep an eye out for sales in mid-August.

A good book is another optional but handy piece of equipment for both freezing and canning. You can read it and get an idea of what you want to do, and a book will also have canning recipes.