USDA Approves Steam Canners

Many home preservers love steam canners (such as the Victorio), because they use less water and less energy and take less time to preheat than boiling-water canners. For at least two decades, however, the USDA and its Extension employees have warned that steam canners may be dangerous. This has kept a lot of people from buying steam canners and has made the people who swear by the devices at least a tad nervous.

A 2003 position paper published by Oregon State University detailed the concerns: Cold spots might occur between the jars or under the dome; steam might lift the lid of the canner, which would allow cold air to enter; jars might break or heat unevenly; the user might mistake cool vapor for steam and so might underprocess the jars; the user might be burned by steam.

The fears of breaking jars and uneven heating always seemed bogus to me. The supposed problem was that the jars weren’t separated by a rack. Racks that come in boiling-water canners are usually divided into sections, one per jar, but many people do their boiling-water processing with unsectioned cake racks or pressure-canner racks or even with towels instead of racks. Most home preservers know better than to jam their jars tightly together in a canner.

I’ve never used a steam canner myself, but I’m pretty sure that the vent holes in the side must keep the lid from lifting off like an umbrella in the wind.

Steam burns seem like a true risk with steam canners, but you get a faceful of steam if you’re careless in opening a boiling-water canner, too.

Now Dr. Barbara Ingham, of the University Wisconsin-Madison, has actually done some research on steam canners, and she has found they work pretty well. She has convinced the National Center for Home Food Preservation, the USDA division that oversees home canning, to approve the use of steam canners.

Dr. Ingham, however, identified one important limitation of steam canners: They hold too little water to allow for processing times of more than 45 minutes. This presents no problem for pickles and jams, but the USDA recommends processing tomatoes for long periods, from 35 to 85 minutes (or even longer at high altitudes), depending on how the tomatoes are prepared. You could use a steam canner for tomato sauce or juice, but a boiling-water canner or even a pressure canner is probably a better choice. If the boiling is too vigorous in a steam canner, Dr. Ingham found, the pan can boil dry in twenty minutes.

Dr. Ingham suggests some guidelines to follow with steam canners:

  • Use USDA recipes; don’t rely on the instructions that come with the canner.
  • Fill the jars with hot liquid, and put them into the canner while they are still hot.
  • Make sure that a 6- to 8-inch jet of steam streams from the vent holes throughout the processing period.
  • If possible, check the temperature of the steam—it should measure 212 degrees F—by inserting a thermometer through a vent hole. (Actually, if you live above sea level the temperature will be somewhat lower.)
  • If you’re canning at an altitude of 1,000 feet or higher, you should process your jars longer, just as you would in a boiling-water bath.
  • Let the jars cool at room temperature, as usual.

According to Jeanne Brandt, Family and Community Health director for Oregon State University Extension, OSU still doesn’t like steam canners. But I think I might give one a try.

 

A Better Boiling-Water Canner?

tamale steamer cum canner
An aluminum tamale steamer serves as a rust-free, extra-tall canner.

I’ve always hated my graniteware canner. You know what I mean—one of those big, lightweight, speckled black pots with the cheap chromed rack inside. My rack rusted out in the first year of use. After I replaced it I noticed the pot itself was rusting, too, as the thin enamel coating flaked off the steel in spots. My jars always came of the pot covered with metallic scum. I couldn’t use the pot for sterilizing empty jars, or the scum would end up all over the interior of the jars. Worst of all, the canner wasn’t quite tall enough for quart jars. I couldn’t cover them with even a half-inch of water (the U.S. Department of Agriculture recommends submerging jars by 1 to 2 inches) without the water boiling over and putting out the stove flame.

My graniteware canner is old, I admit—about thirty years old, I’d guess. But canners of this type haven’t improved. The 21- to 21.5-quart models—intended to hold seven quart jars—are still only 9.75 to 10 inches tall. If the specs give a greater height, the manufacturer is probably measuring from the base of the pot to the top of the lid handle.

Although I haven’t thrown out my rusty old canner, it has sat undisturbed in the garage for many years. For boiling-water canning I mostly use my two stainless-steel stockpots, along with the stainless-steel racks that I bought to fit each of them. This setup works perfectly for processing pint and half-pint jars.

But even the taller stockpot is too short for quart jars. So for canning tomatoes, fruits, and juices I’ve substituted my old pressure canner, with the lid left loose. This isn’t the best solution, though, because the thick aluminum wall of the pot takes a long time to transfer heat.

That’s why I started looking longingly at the tamale steamers in the grocery store. These aluminum pots are heavy enough to be sturdy, but light enough to heat up quickly. They come in various sizes: 12, 20, 32, and 50 quarts. Each pot has an indentation around the side, two inches or so from the base, to support a perforated rack. I figured that one of the bigger pots ought to make a good canner.

And so I bought the second-largest size, 32 quarts, and tried it out with quart jars of quince juice. The interior diameter of this pot measures only 14.5 inches, compared to the 15.75-inch width of my graniteware canner, yet seven quart jars fit roomily in the tamale steamer. I could even fit in an eighth jar while retaining at least a quarter-inch of space between the jars.

Even with its raised rack, the tamale steamer is plenty tall—13.5 inches. I can cover my quart jars with 2 inches of water and not worry at all about a boilover. With this pot, I can properly submerge even 1-liter Weck juice bottles.

One problem with the steamer is that it’s made for steaming, not boiling. The rack rests so high that you need about 6.5 quarts of water just to reach its level. All of that water takes a long time to heat. This might not be a concern when you are canning all day long, but heating so much water for a single batch seems wasteful

The solution is easy, though: Next time I process quart jars I’ll take out the raised rack and set a smaller one, probably borrowed from my pressure canner, in the bottom of the tamale steamer. With such an adjustment, the 13-inch-tall 20-quart steamer would be adequate for processing quart jars. In fact, the 20-quart steamer might even be tall enough for quart jars even with the raised rack in place.

Aluminum tamale steamers aren’t expensive. I paid $25 for the 32-quart pot. In comparison, graniteware canners range in price from about $20 to about $40.

So, consider treating yourself soon to a superior boiling-water canner—and treating your friends and family to a big Christmas tamale party.