Can You Pressure Can in an Electric Multicooker?

If your electric multicooker has a "Canning" button on the front panel, read this before you point it at green beans, chicken, or soup. The answer is no, and the reason is a lot more specific than "it has not been approved."

Below is what researchers found when they put temperature loggers inside the jars, why climbing in elevation makes it worse, and the one electric appliance an extension service does point people toward. You also get a two-question test you can apply to any appliance claim yourself, without waiting for someone to publish a verdict on it.

The pressure gauge is a thermometer in disguise

Low-acid food has to reach 240 degrees F to destroy Clostridium botulinum spores, and no amount of extra time at boiling will get it there. A canner reaches that temperature by raising the pressure inside, which raises the boiling point of the water.

So the pressure number was never the goal. It is the setting that happens to produce 240 degrees F under one specific set of conditions. Colorado State University Extension says it plainly: at sea level to 2,000 feet, 11 pounds of steam pressure will produce that temperature.

Change the conditions and the same number lands somewhere else. Water boils at 212 degrees F at sea level, 208 at 2,000 feet, 203 at 5,000 feet and 193 at 10,000 feet, per that same CSU guide.

That is why the published tables push the pressure up as you climb rather than leaving it alone. CSU's table of the pressure required to reach 240 degrees F gives 12 pounds at 2,001 to 4,000 feet, 13 at 4,001 to 6,000, 14 at 6,001 to 8,000 and 15 at 8,001 to 10,000 feet.

SDSU Extension publishes the same 11-to-15 pound ladder for a dial gauge, though it draws the bands slightly differently, stepping up to 13 pounds from 3,001 feet where CSU holds 12 pounds until 4,001. It also gives the weighted-gauge version, which has only two settings: 10 pounds up to 1,000 feet, 15 pounds above it.

The National Center for Home Food Preservation compresses the whole principle into one sentence in its statement on multicookers: "What matters is temperature, not pressure." That Burning Issue statement also names a second way pressure can mislead you. If air is mixed in with the steam, the temperature is lower than the same pressure of pure steam would give. Venting a stovetop canner before you let pressure build is how you get rid of that air.

What happened when someone logged the temperature inside the jars

Utah State University Extension ran the experiment this question deserves. Researchers processed low-acid food in three brands of electric programmable pressure cooker, at three Utah elevations, with high-temperature dataloggers recording temperatures inside the jars rather than in the chamber.

The foods were raw green beans, cooked chicken strips and cooked pinto beans. The elevations were St. George at 2,900 feet, Provo at 4,500 feet and Monticello at 7,100 feet. The benchmark, in USU's own words, was "the common commercial standard of 250 F for 2.5 minutes in the interior of the food."

Food was frequently under-processed. Performance got worse as elevation rose. And the results did not repeat: identical trials, same appliance, same food, came out differently.

That last finding is what closes the question. An appliance that under-processes by a consistent margin could at least in principle be corrected with a longer time. An inconsistent one cannot be, because you have no way to know which run you just got, and checking means opening the jar you were trying to seal. USU's conclusion: "Electric programmable pressure cookers of any brand are inconsistent at higher altitudes and should NOT be used for low-acid canning."

Worth knowing what the study does not tell you. USU's research page describes the three units only as brands picked for popularity, price, and whether the manufacturer marketed them as canners, and does not name which models they were. Cathy Merrill, the USU Extension faculty member who led the project, described it as preliminary work in a May 10, 2019 write-up: "we've determined that electric pressure cookers do not always reach or sustain the temperatures necessary for canning low-acid food safely at Utah altitudes."

By the time the team published a February 2020 factsheet, the language had hardened. It calls the practice a food safety hazard, "with a high risk of producing home canned foods that could develop the deadly botulism toxin."

Your process time is not the whole process

Here is the part that catches out anyone who assumes a longer cook fixes everything. The published process time is not the only window in which spores are dying.

NCHFP spells this out as one of its reasons for refusing to extend USDA processes to these appliances. Those times "rely on a combination of heat from the time the canner is coming to pressure, during the actual process time, and then during the early stages of cooling the canner and jars." Retained heat during the slow natural cool-down is counted into the total sterilizing value deliberately, which is part of how the times stay short enough to leave the food worth eating.

Shorten the cooling and you delete lethality the recipe was relying on. NCHFP names using a very small cooker as one of the ways that happens.

How much of the killing lives in the cooling phase? Etzel, Willmore and Ingham put a number on it in Food Science & Nutrition, processing applesauce, tomato juice and cranberries in pint jars and computing lethality separately for each phase. Cooling contributed roughly 90 percent of the total for applesauce and about 60 percent for tomato juice and cranberries.

Those figures come from a boiling water canner with high-acid foods, not a pressure canner with green beans, so do not carry the percentages across. What does carry across is the direction and the rough size of the effect. Cooling is not idle time tacked on the end, it is a large share of the process.

The same paper turned up something that makes this impossible to eyeball. The geometric center of the jar is the last spot to heat, and for exactly that reason it is also the last to cool, so the cold spot during heating becomes the hot spot during cooling.

Why "it reaches 15 psi" is the wrong claim to make

NCHFP's objection is not that multicookers are weak. It is that the USDA numbers describe a different machine. Its recommendations "were determined for stovetop pressure canners which hold four or more quart-size jars standing upright."

Jar geometry is part of the process, not a detail. NCHFP points out that the position of the jars and the flow of steam around them both affect the temperature inside them, and that jars piled together on their sides should be expected to behave differently from jars standing upright on the canner base.

Then there is the electrical question NCHFP raises and pointedly leaves open: do power surges or drops make the temperature dip, and how would you as the user ever know? A stovetop dial or a rocking weight gives you continuous feedback. A sealed appliance showing you a program step does not.

Vicki Hayman of University of Wyoming Extension states the gap as of its February 5, 2024 review: "There has been no research by the USDA or a university to show that these electric multi-cookers can safely process low-acid food."

The one electric appliance that clears the bar

There is one electric appliance an extension service does recommend by name, and what separates it is architecture rather than branding. The Presto Precise Digital Pressure Canner controls temperature instead of pressure.

Presto's own documentation says the unit "directly monitors the actual temperature within the pressure chamber to control the unit itself," holding it between the 240 and 250 degrees F required for safe pressure canning "without regard to the pressure." Because temperature is the controlled variable, the company states the process "is not affected by elevation," so there is no altitude pressure lookup to get wrong.

Presto also describes doing the development work NCHFP asked manufacturers for: "multiple thermocouples to assess temperatures at many different locations inside the unit," including one inside each jar of food during testing.

NDSU Extension recommends that model by name in its guide to using pressure canners, and draws the line in the same breath: "Multicookers and other types of pressure cookers are not recommended for home canning."

One caveat is worth keeping straight, though. The thermocouple data above is Presto's own development testing, not independent published research. That is a real step up from a bare pressure claim, because it is the documentation NCHFP asked manufacturers to produce, but it is not the same class of evidence as the USU work that tested the multicookers.

The two questions to ask about any appliance

You do not have to wait for a published verdict on each new product. Two questions get you most of the way.

First, which variable does it control? If the answer is pressure, ask what it does above 2,000 feet, because holding a fixed pressure while you climb means holding a falling temperature. If the answer is temperature measured inside the chamber, elevation stops mattering, for the same reason CSU has to publish that table in the first place.

Second, what did they measure while developing it? "Reaches canning pressure" is not the claim that matters. "Temperature logged inside the jars, at every jar position, through come-up, hold and cooling" is the claim that matters, and it is the one NCHFP says is missing.

Once you are at the stove with a canner that qualifies, the rest is lookup work. Our Pressure Canning Time Lookup pulls up the USDA process time for a given food, jar size and pack style in one screen, so you are not paging through PDFs with wet hands. The pressure setting is the other half of the job, and it is the half that moves with your elevation, so check it against the published table for your altitude every single time.