Canning Mistakes: What to Do When Something Goes Wrong

A while back, someone wrote in about green beans she’d canned from her garden. She’d used a water bath, and the jars sealed just fine sitting on the counter. The problem was, green beans are low acid, and low acid foods need a pressure canner, not a water bath. By the time she realized it, five days had already gone by. She wanted to know if there was any way to fix it.

That question comes up a lot, and so does a very different one right behind it: “my jar just didn’t seal, can I reprocess it?” Both are about green beans and reprocessing, but they’re not the same situation, and they don’t follow the same rule.

When can you reprocess home canned food?

The short answer.

• If you followed a tested recipe correctly and a jar just didn’t seal, you have 24 hours to reprocess it.
• If something went wrong with how you processed it, like the wrong time or a canner that lost pressure and didn’t finish, the window is 2 hours, not 24. (I’ll explain more why.)
• If you used the wrong method entirely, like water bathing green beans instead of pressure canning them, no amount of time makes reprocessing that batch safe.

Two Different Situations, Two Different Rules

Your Jar Just Didn’t Seal (the 24-Hour Rule)

This is the most common version of the question. You followed a tested recipe, you used a pressure canner for your green beans like you were supposed to, and everything went the way it should have. The problem is, the lid didn’t seal. Maybe it was because of a small nick on the jar rim or a bit of food caught under the lid. Sometimes you just don’t know why. But you know you did everything according to tested directions.

If that’s your situation, you have 24 hours from when you canned it to reprocess the jar. The National Center for Home Food Preservation (NCHFP), the research group most canning safety guidance traces back to, has this guidance: reprocessing is only considered safe if you followed a tested recipe on your first attempt and you reprocess within that 24-hour window.

Something Else Went Wrong (the 2-Hour Rule)

Not canning correctly is a different problem. Maybe your canner lost pressure partway through and you didn’t restart the timer. Maybe you used the wrong processing time. For this situation, the window is 2 hours, not 24. After that, the food needs to be thrown out rather than reprocessed.

This isn’t published on NCHFP’s own website yet, so I want to be transparent about where I verified this. (I went around and around in circles to different sources! It got confusing.) My sources are at the bottom of this article.

• NCHFP’s general storage and reprocessing guidance covers the 24-hour rule directly.
• The 2-hour figure for a processing error comes from a written response from NCHFP staff to Iowa State Extension’s AnswerLine.
• The same 2-hour guidance also shows up independently on Penn State Extension’s and University of Nebraska-Lincoln’s canning pages, both citing NCHFP as the source.

It’s a real current recommendation, it just hasn’t made it only the NCFHP’s site yet. I’m not sure why, I’ll update this if they ever mention it directly on the site.

There are a lot of variables that go into whether a specific processing error is safely fixable within that 2-hour window, more than I can walk through for every situation here. My honest advice: if you’re not sure, don’t try to talk yourself into it. Toss that batch, chalk it up to something to do differently next time, and keep canning. One lost batch isn’t a failure, it’s just part of learning the process.

General Food Safety and Why 2 Hours Makes Sense.

Worth knowing too: this 2-hour window is the same principle behind the general food safety rule for how long perishable food can sit at room temperature before bacteria start multiplying. It’s not a coincidence, and it’s part of why the two canning rules get confused with each other. More on that in Reprocessing Canned Food: The 24-Hour Rule vs. the 2-Hour Rule.

If You Didn’t Follow a Tested Recipe At All

NCHFP is clear that if a tested recipe wasn’t followed on the first attempt, all the jars, sealed or not, may be unsafe and should be discarded. No waiting period fixes it.

How to Reprocess Green Beans

All right, lets say you decided reprocessing is safe. (Within whichever time frame applies to you.) Here is how to do it.

You’ll redo the entire process. As a hot pack. These beans are no longer raw. You must do a hot pack.

1. Empty the jars into a pot and bring the beans back to a boil.
2. Pack the reheated beans into clean jars, leaving the correct headspace.
3. Wipe the rims, apply new lids, and process for the full time your recipe calls for, adjusted for your altitude.

Note. You need to have realistic expectations of reprocessed green beans. They’ll probably get soft, sometimes mushy. They’re still safe to eat, they just won’t have the same texture. They are fully cooked… twice.

Freezing or Refrigerating Instead of Reprocessing

Reasons not to reprocess: Maybe you just don’t have the time, freezing or using the food up is quicker. Maybe you don’t like overly soft green beans.

If you’re still within your window but you’d rather not reprocess, freezing or refrigerating are safe alternatives, as long as you act within that same window.

• Freezing: Remove the beans from the jar into freezer bags or containers. If you’d rather leave them in the jar, take some out first so there’s room for the food to expand as it freezes.
• Refrigerating: This works well for a jar or two you’ll use soon. NCHFP’s guidance is to consume refrigerated jars within one week.

Personally, I don’t remember ever reprocessing anything. To me, it’s not worth the time. I just put the unsealed items in the fridge to use, or freeze them. Depends on what it is.

Once You’re Past the Window

Once you’re past your window of safety, none of these options apply anymore, not reprocessing, not freezing, not the fridge. Those time limits exist because that’s the point where spoilage organisms or botulism risk can no longer be ruled out, and no amount of cold storage changes that. At that point, the safest thing to do is let it go.

Related Questions

Can you reprocess green beans a second time if the reprocess also fails?

No. At that point, freeze what’s left or refrigerate it for near-term use, or simply toss it instead of trying again.

What if you used a water bath instead of a pressure canner on green beans?

Green beans are low acid and need a pressure canner. If they were water bathed instead, that batch should be thrown out rather than eaten or reprocessed, regardless of how the seal looks. For the full explanation of why water bath canning doesn’t work for green beans see Is Water Bath Canning Green Beans Safe?

Do the reprocessing steps change based on jar size?

No, the process is the same for pints and quarts. Just process for the correct time for your jar size, and adjust for your altitude.

Related Reading

• 3 Canning Methods, Which Do I Choose?

Sources

Food safety claims in this post are backed by the following, listed in the order they’re referenced above.

• NCHFP: Storing Home Canned Foods — the 24-hour rule for a correctly processed jar that didn’t seal – https://nchfp.uga.edu/how/can/general-information/storing-home-canned-foods/
• NCHFP: Using Pressure Canners — restarting the timer if pressure drops during processing –
  https://nchfp.uga.edu/how/can/general-information/using-pressure-canners/
• Iowa State Extension AnswerLine — the 2-hour rule for a processing error, from a direct written response by NCHFP staff – https://blogs.extension.iastate.edu/answerline/2024/08/20/canning-mistakes-but-my-jars-sealed/
• Penn State Extension: Ensuring a Good Seal on Canned Goods — corroborates the 2-hour guidance – https://extension.psu.edu/ensuring-a-good-seal-on-canned-goods
• University of Nebraska-Lincoln: Saving Home Canned Food – Jars Did Not Seal — corroborates the 2-hour guidance – https://food.unl.edu/saving-home-canned-food-jars-did-not-seal