Rebel Canning: What It Is, Why It’s Trending, and Why USDA Says No

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In June 2018, three women in New York City ended up in intensive care for between 34 and 54 days. Two needed emergency intubation. All three survived, but only after antitoxin and months of rehabilitation.

The cause, per CDC’s outbreak report: the woman who canned the food used a peach preserves recipe with a boiling water technique and replaced the peaches with frozen vegetables. She was a novice, she was not being reckless, and she did not know that low-acid foods must be pressure canned.

That is rebel canning in one sentence — take a tested recipe, change the food, keep the process. And it is the cleanest illustration of the thing this whole argument turns on: the process is validated for the food, not for the recipe card.

What rebel canning is

The term grew out of the “Canning Rebels” Facebook community, founded by Milissa Chapman in roughly the early-to-mid 2010s, and reached mainstream food media around August 2023. It now spans dozens of Facebook groups, plus TikTok and YouTube, with membership somewhere in the tens to hundreds of thousands.

The group’s motto is “your kitchen, your rules.” Chapman: “As far as I’m concerned, it’s nobody else’s business — what you do in your kitchen, what you feed your family.” And: “I let the ancestors guide me, as they say.”

Practices under the umbrella include water-bath canning low-acid foods, canning butter and milk, dry canning raw vegetables, oven canning, open-kettle canning, inverting jars to seal, reusing lids, and freely altering tested recipes.

Their argument, put fairly

An article that treats these people as idiots will not persuade any of them, and it would also be wrong. So here is the case at its strongest.

Cost is real. One member reports canning cut his grocery bill by 75%. That is a serious household economics argument.

Ancestral practice is real. Many of these canners learned from mothers who learned from grandmothers during the Depression. That is genuine transmitted competence, not ignorance.

And the complaint about variety is simply correct. There is no USDA-tested process for milk, butter, cheese, eggs, most purées, pumpkin butter, pesto, or any soup thickened with flour or cornstarch. A canner who wants shelf-stable versions of those foods is told no, with no approved alternative offered. The tested catalog is genuinely narrow, and pretending otherwise is dishonest.

These are mostly people with real kitchen skill, operating in the one domain where the failure mode is invisible, delayed, and rare enough that personal experience is a systematically misleading teacher. That is a cognitive trap, not a character flaw.

One mechanism explains nearly every prohibition

If you understand three facts, every rule below stops being arbitrary.

1. Water is the heat-transfer medium. Canning process times are validated using water or steam — a known temperature, with high heat capacity and efficient transfer. Air is a poor conductor with no fixed temperature. Substitute air and the jar’s cold spot never reaches what the process assumes.

2. Boiling water cannot exceed 212°F. At atmospheric pressure that is physics, not policy. Botulinum spores require 240°F to 250°F. This is not fixable by processing longer — it is a temperature the method cannot produce at any duration.

3. pH 4.6 is the line. Above it, in a sealed moist jar at room temperature, C. botulinum can grow and produce toxin.

Now every practice falls out of those.

The practices, and why each fails

Water-bath canning low-acid foods

The one with the documented body count. CDC: “Home-canned vegetables, which are low-acid foods, are the most common cause of botulism outbreaks in the United States,” and “Do not use a boiling water canner for low-acid foods because it will not protect against botulism.”

CDC also rules out electric multicookers explicitly: “Do not use an electric, multi-cooker appliance, even if it has a ‘canning’ or ‘steam canning’ button on the front panel.” The button on the appliance is not a validation.

Dry canning raw vegetables

NCHFP calls this “very hazardous.” Raw vegetables packed with no liquid, pressure canned at standard times. The liquid is “required for the expected heat penetration throughout the jars,” and separately, “bacteria and bacterial spores are more sensitive to wet heat than dry heat.”

So you have air pockets instead of water, and spores that die far more slowly in dry heat. Same minutes, same temperature reading, a fraction of the lethality. NCHFP also rejects substituting butter or ghee for the liquid — fat makes it worse.

Dry canning dry goods — a different practice, don’t conflate them

Oven-heating jars of flour or rice to force a seal is a separate thing. NCHFP: “It is not a food preservation method we recommend” and “this process is not ‘canning’ just because it uses canning jars.” The objection here is that sterilization is unproven and there is no researched shelf life — plus jar breakage risk.

With genuinely dry goods the botulism risk is low, because water activity is low. But do not generalize that. Any product with residual moisture lands straight back in the risk category.

And there is an approved path: vacuum sealing with jar adapters at room temperature, oxygen absorbers, or freezing before packaging. Our guide to Mylar bags and oxygen absorbers covers the method that actually works.

Canning dairy — butter, milk, cheese

Clemson HGIC: “There are no science-based methods for home canning of cheeses, milk, butter or other dairy products.”

Four separate mechanisms, all interesting:

• pH. Cheese runs 5.1 to 5.9 — squarely in the danger range. Butter, milk, and cream are low-acid and “will support the outgrowth of C. botulinum and toxin formation in a sealed jar at room temperature.”
• Fat shields spores. “Fats can protect spores from heat during a canning process.”
• Water activity moves the wrong way. Hard cheese is shelf-stable because it is dry and salty; canning adds moisture, and “increased available water may allow C. botulinum to grow.”
• You kill the competition. “Boiling waterbath canning processes kill the competitive ‘good’ bacteria that help prevent the growth of C. botulinum.” Mild heat can make a food more hospitable to botulism by removing its competitors while leaving its spores intact.

On canned butter specifically, Clemson’s reframe is exact: “This process is merely storing butter in canning jars, not canning.”

Oven, dishwasher, microwave, slow cooker, sun

South Dakota State Extension gives the mechanism for each. Ovens: heat distribution is uneven, dry heat penetrates slowly, and jars “may crack or explode.” Dishwashers: no control over temperature, pressure, or time, and cycles never reach a lethal temperature. Microwaves: no standard temperature, uneven distribution, no published research. Slow cookers and sun canning: nowhere near hot enough.

All the same failure — air substituted for water, or a temperature that was never validated.

Open-kettle canning and jar inversion

Penn State: heating food, pouring it into jars, and letting residual heat seal the lid. The food “may not be heated adequately to destroy spoilage organisms, molds, and yeasts,” and it does not produce a strong seal. “Never open kettle can low acid foods.”

Inverting jars is open-kettle with an extra step, and the inversion actively works against the seal — hot food flowing across the sealing compound while the gasket is softening can leave residue and produce a weak or false seal.

Reusing lids

NCHFP: “Lids should not be used a second time since the sealing compound becomes indented by the first use, preventing another airtight seal.”

The gasket is a single-deformation part. It softens, conforms to that jar’s rim, vents air, and sets. Once set it holds a permanent impression and cannot re-conform. Jars and bands are reusable indefinitely; flat lids are not.

Altering tested recipes

Penn State gives the mechanisms plainly. Flour, cornstarch, rice, pasta: “starch interferes with heat transfer during processing.” Dense purées like mashed pumpkin or refried beans: “the density of the product prevents heat from reaching the cold spot in the jar” — which is exactly why NCHFP approves cubed pumpkin but not mashed. Oil and pesto: “oil coats any herb or food placed in it, creating an ideal environment for Clostridium botulinum to grow.” Extra low-acid vegetables in salsa: raises pH above 4.6 and changes heat penetration at the same time.

One case worth noting because it shows the guidance is not uniformly fear-driven: broccoli, cauliflower, and summer squash are not unsafe to pressure can — the temperatures required would simply make them mush. There is no tested recipe because the result would be inedible.

“My grandmother canned this way for fifty years”

This is the strongest emotional argument and it deserves a real answer rather than a dismissal.

First, the rarity is real — and it is produced by the rules. A UC Master Food Preserver article addresses the objection head-on: “Low case counts mean prevention works.” And: “The success of these safeguards can create a dangerous illusion that shortcuts are harmless. One person’s uneventful history with a method does not make that method safe. It means the person has been fortunate.”

Second, the denominator is hidden. Jars quietly discarded because they looked off never enter anyone’s story. Neither does the household member who ate one bad jar while nobody connected it to anything. Contamination is patchy and unpredictable — a method that “worked” 200 times has drawn 200 times from mostly-safe lots. It has not been tested.

Third, here are the honest numbers. In 2021 CDC recorded 273 total botulism cases nationally, of which only 22 were foodborne, with 5 confirmed cases linked to home-canned foods. Across 2001–2017 there were 53 foodborne outbreaks, 326 confirmed cases, and 17 deaths — a 5% case fatality rate, with about 76% involving home preparation.

So: roughly 20 confirmed foodborne cases a year in a country of 340 million. Botulism is genuinely rare and anyone telling you otherwise is overselling. The argument is not frequency. It is that this is a low-probability, catastrophic-severity risk whose entire prevention cost is owning a pressure canner and following a tested recipe. The insurance premium is trivial relative to the loss.

Yes, the guidance has changed — and tomatoes prove why

The community’s sharpest point is that the rules keep changing, so why trust them now. The honest answer is that they changed in one direction, on evidence, and USDA documents it.

A 1905 USDA bulletin actually recommended oven canning as “the one to be preferred.” Then 1917 established pressure canning as the only safe method for low-acid foods. By 1940 an Extension bulletin called oven canning influenced by “so many variable factors that it cannot be recommended.” By the mid-1940s USDA was campaigning against it over documented explosions and injuries. Open-kettle canning was formally classified unsafe in the 1980s, though USDA had flagged its defects as early as 1936.

Then tomatoes. Clemson’s explanation is the killer detail: modern varieties have been bred for harvest characteristics rather than flavor and acidity, and testing has found some at or above pH 4.6 — a few at pH 5 or higher. USDA: “Although tomatoes usually are considered an acid food, some are now known to have pH values slightly above 4.6.”

Which inverts the grandmother argument entirely. Grandma’s tomatoes may genuinely have been safe unacidified. Yours are not the same tomato. The plant changed, so the guidance changed. Doing what grandma did is not the conservative choice — it is applying a 1950s process to a 2026 ingredient.

And guidance moves both ways: NCHFP has withdrawn recommendations too, including dry-packed shelled nutmeats. This is a research program, not a ratchet.

The steam canner: proof the system works

Atmospheric steam canners were folk practice. Extension discouraged them. Researchers tested them. In 2015 the guidance changed to accept them — for naturally acid or properly acidified foods at pH 4.6 or below, under six specific controls: air vented before timing starts, pure steam at boiling temperature throughout, jars preheated, processing time 45 minutes or less including altitude adjustment, canner never opened during processing, and cooling in still ambient air.

The 45-minute cap is a capacity limit — the reservoir can boil dry — not a lethality one.

Steam canners are not rebel canning, and lumping them together would be an error. They are also the best evidence for the community’s own case: the difference between an approved method and a rebel one is not obedience versus rebellion. It is tested versus untested. The path exists. Someone did the work.

What you actually can change

Any article implying nothing is adjustable loses credibility, and it would be false. Extension publication FN2102 lists genuinely safe modifications:

• Seasonings — up to 1 tsp per pint or 2 tsp per quart of dried seasoning, onion, or garlic. A garlic clove or dried hot pepper in pickle jars.
• Sugar — reduce, eliminate, or swap for honey in canned fruits, sauces, salsa, and tomato recipes. It is flavor, not preservation.
• Salt — in canned vegetables, meats, and fruits, salt is flavor only and may be reduced or omitted. Note the exception: in fermented pickles and sauerkraut, salt concentration is load-bearing and must not change.
• Substitutions within a class — peaches for nectarines, sweet for hot peppers measure-for-measure, any onion color, cider for white vinegar at the same 5% acidity.
• Smaller jars — a 12-ounce jar in place of a pint, processed for the original time. Never larger.

Worth saying plainly: using table salt instead of canning salt is not a safety issue. Anti-caking agents cause cloudiness, not danger. Chapman cites it as rebellion; it is not one.

Never changeable: processing time or temperature, larger jar sizes, the canning method, acid content, thickeners, added fat or oil, added low-acid vegetables, headspace, and altitude adjustment.

The organizing principle: you may change what the food tastes like. You may not change what determines whether heat reaches the center of the jar, or what the pH is when it gets there.

Where to get tested recipes

NCHFP publishes the full USDA Complete Guide to Home Canning free at nchfp.uga.edu, organized by food type. Ball’s Fresh Preserving site carries tested recipes, as do the printed Ball books. Your state Extension office will answer questions about untested recipes directly, at no charge.

If you are canning low-acid food, a pressure canner is not optional equipment — see our pressure canner comparison and the breakdown of water bath versus pressure canning. Browse pressure canners if you do not own one.

Key takeaways

• Boiling water cannot exceed 212°F; botulinum spores need 240–250°F. No amount of extra time fixes that.
• Water is the heat-transfer medium — dry canning, oven canning, and open-kettle all substitute air and invalidate the process.
• There are no science-based methods for canning dairy. Fat shields spores and mild heat kills the competing organisms.
• Botulism is genuinely rare — about 20 confirmed foodborne cases a year — but roughly 5% fatal even with modern care.
• USDA guidance has changed repeatedly, always toward caution, and oven canning was USDA-preferred in 1905.
• Modern tomatoes are less acidic than historic varieties. Acidification is not optional.
• Atmospheric steam canners are approved for acid foods under six controls — tested, not rebel.
• Seasonings, sugar, salt, and same-class substitutions are safely adjustable. Time, temperature, method, acid, jar size, and headspace are not.

Frequently asked questions

Is there a safe way to can butter if I’m careful? No. There is no tested process, and the failure modes are structural rather than technique-dependent — fat shields spores from heat regardless of how carefully you work. If you want shelf-stable butter, ghee stored properly or commercially canned butter are the real options.

Why does USDA have no recipe for the thing I want to can? Usually because testing has not been funded for it, sometimes because the food is physically untestable — too dense for reliable heat penetration, or too variable in pH. The absence of a recipe is not permission to invent one; it means nobody knows what process would work.

Can I ask someone whether my own recipe is safe? Yes, and you should. Your county Extension office will evaluate a recipe and tell you whether an equivalent tested process exists. It is free, and it is a considerably better source than a Facebook group with 70,000 members and no laboratory.