Water Bath or Pressure Canner: Which One Do I Need?

The answer comes down to one thing: acid.

High-acid foods → water bath canner. This covers most fruits, jams and jellies, pickles made with a tested vinegar recipe, and tomatoes with added acid. The acid in these foods keeps botulism from growing, so boiling-water processing is enough.

Low-acid foods → pressure canner. This covers vegetables, beans, meat, poultry, seafood, stocks, and soups. These need the higher temperature only a pressure canner reaches.

The foods people get wrong

• Tomatoes sit near the line. Tested recipes call for added lemon juice or citric acid in every jar, even for water bath processing.
• Salsa and mixed vegetables: adding peppers and onions to tomatoes lowers the acidity. Use a tested salsa recipe exactly, and don't improvise ratios.
• Pickled vs. plain: pickled green beans can go in a water bath using a tested recipe, while plain green beans need a pressure canner.
• "Just add more time" doesn't work. A longer water bath does not make low-acid food safe.

How to stay safe

• Use a tested recipe for the specific food and jar size.
• Adjust for altitude.
• Check seals after 24 hours. Refrigerate and use any jar that didn't seal.
• If a sealed jar is bulging, leaking, spurting, or smells off, don't taste it. Follow NCHFP guidance for disposal.

Where experience earns its keep. Jams are a forgiving place to learn. The jump to low-acid pressure canning is where a mistake doesn't show up until someone eats it, so it's worth doing the first low-acid batch next to someone who's done it for years.