Practicality of the Pressure Canner
By Victoria Redhed Miller | Jul 31, 2017
Igrew up in Seattle, Washington, in a family with eight children. My mother was a stay-at-home mom, and she has always cooked virtually everything from scratch. Grocery store sale ads appeared in the Wednesday newspaper, and Mom would plan a week’s worth of meals based largely on what was on sale that week. I was interested in cooking when I was quite young, and Mom often let me cook for the family. I’m so thankful that I learned to cook the way she did — economically and in quantity.
The high school I attended in north Seattle required girls to take home economics in 9th grade. Frankly, I was bored most of the time in this class; I already knew how to make bread, bake an apple pie, and boil pasta. I will always be grateful for that class, though, because it was there that I learned the basic principles of canning. I don’t remember exactly what we canned (probably some kind of jam), but the idea of safely preserving perishable food to be consumed weeks or months later was a kind of epiphany for me.
Throughout my high school years, Mom and I, and sometimes my sisters, did a lot of canning every summer and fall. We always had a vegetable garden, and the old pear tree by the back porch yielded a good crop every other year. The whole family would pile into our Ford van and head out to the U-pick farms near Seattle: strawberries in June, raspberries in July, and blueberries in August. Dozens of jars of beautiful jams, jellies, pears, tomatoes, and pickles crowded the pantry. Later, Mom got a pressure canner, and the shelves filled even more quickly with marinara sauce, homegrown green beans, and other low-acid foods.
Mom always said two things when we proudly surveyed that stockpile of delicious food: “This makes me feel rich,” and “This is my idea of convenience food.” She’s so right about that.
The need to can
In 2006, my husband, David, and I moved to our off-grid farm in the foothills of the beautiful Olympic Mountains, about 21⁄2 hours northwest of Seattle. With a lot of enthusiasm and garden space, but only about a cubic foot of freezer space in our small propane refrigerator and freezer, I quickly realized how much I was going to be relying on my canning skills and my pressure canner. This skill became even more important when we began raising free-range chickens, turkeys, and ducks. When it came time to slaughter older hens and extra roosters, being comfortable with the pressure canner was a huge asset.
There aren’t many tools I have around the house that have exactly one use, but my pressure canner is one of them. For all its advantages, it does have some drawbacks. While not prohibitively expensive (about $100 to $150), it is one more thing to buy. Compared to water-bath canning, pressure canning usually involves much longer processing times. Also, because of the high temperatures involved in pressure canning (10 pounds pressure = 240 degrees Fahrenheit), some nutrient loss does occur. On the other hand, for the same reason, meat becomes quite tender, something to consider when canning meat from older birds or other livestock.
So why bother? Well, remember what I said about cooking in quantity? My husband is an absolute pro at grocery shopping; he knows what specific items should cost, and when to wait for them to go on sale. Then, when he finds the best deal (he’s also very picky about quality), he buys a lot of whatever it is. So, if he comes home with 15 pounds of bottom round roast to grind up, I make a big pot of spaghetti sauce or chili, and can it. As with all of my food-preservation efforts, for me this comes down to being economical, and trying not to let anything go to waste.
More than once, after a party, I have used the pressure canner to deal with leftovers. One year we hosted an 80th birthday party for David’s mother and had 40 people over. She was half Portuguese, and I had made a huge pot of a Portuguese-style stew with lamb and homegrown fava beans. We had at least a couple gallons leftover, and it was all canned the next day. We enjoyed that stew for months.
Then there is the poultry flock. We don’t generally raise chickens specifically as meat birds; most of our laying flock consists of New Hampshire hens, an excellent dual-purpose breed. We hatch more chicks (well, the hens do actually) every year, so at some point in the season we have at least a few extra roosters to slaughter. Occasionally we also slaughter some older hens. I get out my 10-gallon stockpot, cook them up, then can the meat and broth separately. Homemade chicken and turkey broth, as well as jars of chicken meat, are things I like to keep on hand when possible because of their culinary versatility. You never know when someone is going to have a craving for chicken and dumplings!
Trial and error
By the time I was in intensive training for my Master Food Preserver certification in 2009, I had already been using a pressure canner for several years. During the class, I heard a lot of scary stories about things going wrong during the pressure canning process. As far as I recall, virtually every instance came down to some kind of operator error: not properly locking the lid in place, overfilling the canner, letting the pressure reach an unsafe level.
It’s true that things can go wrong, and given the high pressure and temperature in the canner during processing, it’s possible to sustain burns or other injuries. Don’t let that put you off. If you read your canner’s instruction manual before you start, take your time, and use it often enough to become comfortable with it, pressure canning can be just as safe and easy as water-bath canning.
Of all the food-preservation methods, freezing results in the least amount of nutrient loss. On the other hand, in the Master Food Preserver class, I heard just as many stories about chest freezer accidents as I did about pressure canners. People with much more food preservation experience told stories, rather sheepishly, about throwing out frozen foods because they could no longer read the labels or dates, and were afraid the food might have gone bad.
For the first nine years of living on our off-grid homestead, we did not have full-time electricity, so a large freezer was not an option. We got our solar electric system up and running in early 2015, but we still do not have a separate freezer. I’m not sure where we would put one, and it’s unclear whether we would generate enough electric power in the winter to keep it constantly running. Honestly, I am so used to the routine of year-round canning that I’m not very motivated to even think about a freezer. As with so many things about the homesteading lifestyle, you will have to figure out what works best for you in your particular circumstances.
If you rely on electricity, especially in a warm climate, it’s worth mentioning that frozen food is vulnerable when the power goes out. Since much of the motivation for preserving food is to be economical and minimize waste, canning may just be the best choice.
The basics of low-acid
What is a low-acid food? A quick review: The pH scale reads from 0 to 14. Anything between pH 0 and 7 is acidic, 7 is neutral, and anything between 7 and 14 is alkaline, or basic. Zero is the most acidic, and 14 is the most alkaline. For canning purposes, low-acid is defined as anything that is pH 4.6 or higher (between pH 4.6 and 7). Meats, poultry, and seafood are all low-acid foods. Most vegetables are also low-acid, unless they are pickled.
Most spoilage bacteria can’t survive in an acidic environment. In addition, molds, yeast, and some bacteria are killed at 212 F, which is why pickles and most fruits and tomatoes (high-acid foods, between pH 0 and 4.6) can be safely processed in a boiling-water bath. Salmonella and staph, however, are only destroyed at temperatures of at least 240 F.
When the pressure canner is properly sealed and heating up, pressure begins to build, which increases the temperature. Most methods for pressure canning low-acid foods require a minimum of 10 pounds of pressure, which is equivalent to 240 F (some books now recommend 11 pounds pressure). Depending on the type of food being canned, processing times vary. Compared to chicken broth, for example, pasta sauce and thick soups like chili take longer to reach the internal temperature necessary to kill spoilage organisms. With my canner, quart jars of broth are processed for 30 minutes at 10 pounds pressure; quart jars of chili are processed for 90 minutes.
Other than the canner itself, all the other equipment for pressure canning is the same as for water-bath canning: Mason jars (see Tip #2 at left), lids and rings, canning funnel, jar lifter, cooling rack. Washing and heating jars is also the same, although with pressure canning, sterilizing the jars is not necessary because of the high heat involved. Two notable differences are the headspace required when filling the jars (generally 1 inch for pressure canning), and the amount of water in the canner itself (3 quarts in mine).
Depending on what you are canning, there are also some choices for methods. For example, when canning meat, you can use either the hot-pack or raw-pack method. Canning soup and broth couldn’t be much simpler. As long as the soup is good and hot, I just ladle it into the jars, leaving the specified headspace, put the lids on, and into the canner they go.
Food safety is what it is all about. Using a pressure canner will probably seem complicated and even a little scary to begin with, but adding this useful tool to your food-preservation arsenal allows you to safely preserve low-acid foods like meat, soups, and broth. As my mother used to say, the convenience of having a variety of ready-to-heat, nutritious homemade foods on the shelf is well worth the time and effort. No matter where you live, if you grow your own vegetables or meat animals, or you just like to buy in quantity to save money, consider making friends with a pressure canner. It will greatly increase the scope of what you can preserve at home, safely and economically.
1. Have your canner’s pressure gauge tested once a year for accuracy.
If testing is not available in your area, be on the safe side and replace the gauge annually.
2. Do NOT use commercial pasta sauce jars (such as Classico brand) that say “Mason.”
These are “one-shot” jars, designed for commercial processing. Use only jars specifically meant for home canning, such as Ball and Kerr brands.
3. Recommendations for processing times and pressures occasionally change.
Use up-to-date resources like the Ball Complete Book of Home Preserving. I particularly like the books Stocking Up (3rd edition) and Putting Food By (4th edition). There’s also tons of information online at sites like www.FreshPreserving.com and National Center for Home Food Preservation,nchfp.uga.edu.
4. As with water-bath canning, processing times generally increase at elevations above 1000 feet.
5. Make sure soups have plenty of liquid.
For thick soups such as split pea, make it thinner than usual before canning. The high heat of pressure canning results in some loss of liquid during processing.
6. Don’t rely on your memory!
No matter how many times you can your homemade broth or chili, it’s smart to look up the processing times every time.
Victoria Redhed Miller is a Certified Master Food Preserver who lives in northwest Washington state. She is a regular speaker at the Mother Earth News Fair and other events, and the author of Pure Poultry and the award-winning Craft Distilling: Making Liquor Legally at Home. Learn more at VictoriaRedhedMiller.com.
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