Can you use an atmospheric steam canner for jam?

Yes. An atmospheric steam canner is safe for fruit jams and jellies as long as you follow the research-based rules: use it only for high-acid foods with a tested boiling water recipe, process for the same time that recipe gives for a boiling water canner (with your altitude adjustment), keep the total under 45 minutes, start timing only when the vent shows a full steam column or 212°F, and preheat the jars [1]. Penn State bases these rules on University of Wisconsin research [1]. Jam fits them better than almost anything else you might can. This page sets out the rules, the procedure, and the mistakes that leave jars underprocessed.

What a steam canner is

An atmospheric steam canner has a shallow base about 3 inches high, a rack that holds the jars above about two quarts of water, and a tall domed cover with one or two vent holes; some models have a temperature gauge in the lid [1]. The jars sit in steam at atmospheric pressure, which is 212°F at sea level, the same temperature as boiling water [1]. It is a different appliance from a pressure canner, which reaches 240°F and is needed for low-acid foods [1]. Jam never needs a pressure canner.

Its appeal for jam makers is real: a few quarts of water instead of a full canner, a much faster heat-up, and a lighter pot to handle.

The five rules

Penn State also asks that jars be heated before filling and that you use standard canning jars with two-piece lids in half-pint, pint or quart sizes as the tested recipe specifies; half-gallon jars cannot be used [1]. For jam, that means half-pints and pints.

Jam times against the 45 minute ceiling

The two jam processing systems in common use run from 5 minutes (sterilized jars, sea level) to 30 minutes (unsterilized jars, 8,001 to 10,000 feet) for half-pints and pints. The full chart and the reasoning behind it are on how long to process jam; USDA's base times come from Guide 7 [2]. Every one of those times is under 45 minutes, so ordinary jam can be steam canned at any elevation up to 10,000 feet. Check longer-processed spreads against the ceiling: Guide 7's peach-pineapple spread, for example, runs 20 to 35 minutes in pints depending on elevation [2], which still fits.

The sterilizing decision works the same way in a steam canner. The steam is at the temperature of boiling water [1], and you are using the boiling water recipe's time, so a 5 minute time still needs jars sterilized first, and a 10 minute time does not [3]. How to sterilize is on do you need to sterilize jars.

Step by step

This follows Penn State's directions [1].

1. Fill the base with about two quarts of water, to just below the rack. The manufacturer cited by Penn State suggests starting with cold tap water rather than softened water, which can contain salts that corrode the metal; a tablespoon of white vinegar is optional.
2. Heat the jars. Keep them in a separate pot of hot water, or partly fill them with hot water and stand them in the canner until you need them. Drain each one just before filling.
3. Preheat the canner water to 180°F for hot-packed food. Jam is always a hot pack.
4. Fill the hot jars with hot jam, leave 1/4 inch of headspace [2], wipe the rims and put on the lids and bands. See headspace.
5. Load the jars on the rack and put on the cover.
6. Heat on medium-high until a full, steady column of steam at least 8 inches long comes from the vent, or until a thermometer in the vent reads 212°F, or until a built-in gauge reaches the zone for your altitude.
7. Start the timer now.
8. Turn the heat down only enough to hold that temperature. The lid should not jiggle and the vents should not whistle. A canner run too hard wastes its water.
9. Do not lift the cover to add water. Steam escapes and the temperature drops.
10. When the time is up, turn off the burner and leave the jars in the covered canner for 5 minutes, which Penn State says reduces siphoning.
11. Lift the cover away from you, since steam and water will be hot, and move the jars to a towel, a wooden board or a rack away from drafts.
12. Cool the jars undisturbed for 12 to 24 hours, then test the seals as on cooling jars and checking the seal.

Testing a built-in temperature sensor

Penn State passes on a yearly check from VKP Brands for canners with a sensor in the lid, also to be done when you move to a different elevation: load four quart jars of water without lids, bring the canner to temperature, lower the heat slowly until the lid stops lifting, rattling or spitting at the edges, then watch the needle. It should reach the green zone for your altitude. Mark the highest point it reaches; that is the reading at which you can start timing [1].

Steam or boiling water: how they compare for jam

What can go wrong

If your canner instructions disagree with any of these rules, follow the extension guidance; the canner booklet is not the tested source.

Your next number: the processing time itself

The steam canner borrows its time from your recipe. To find that time at your elevation, with or without sterilized jars, go to how long to process jam or use the processing time calculator.

References

1. Penn State Extension, Zepp, How to Use an Atmospheric Steam Canner, updated March 17, 2025 (citing Willmore, Etzel, Andress and Ingham, Home Process of Acid Foods in Atmospheric Steam and Boiling Water Canners, Food Protection Trends 35:150-160, 2015). https://extension.psu.edu/how-to-use-an-atmospheric-steam-canner
2. USDA and National Center for Home Food Preservation, Complete Guide to Home Canning, Guide 7: Preparing and Canning Jams and Jellies, revised July 2015. https://nchfp.uga.edu/papers/guide/GUIDE07_HomeCan_rev0715.pdf
3. National Center for Home Food Preservation, Do I need to pre-sterilize my jars before canning?, May 21, 2014. https://nchfp.uga.edu/blog/do-i-need-to-pre-sterilize-my-jars-before-canning
4. University of Georgia Cooperative Extension, Schwan, Beltran and Andress, Preserving Food Series: Using Boiling Water Canners, Circular 1344-01, May 2025. https://nchfp.uga.edu/papers/factsheets/Preserving_Food__Using_Boiling_Water_Canners.pdf