Canning Mistakes That Can Kill You: What to Avoid

Canning Mistake Potential Risk Prevention Method Using Unreliable Recipes Food spoilage, botulism. NEVER make up your own canning recipe. Only follow trusted, scientifically tested recipes. Improper Sterilization Botulism, food contamination. Follow safe, tested canning recipes, always use a pressure canner for low-acid foods, and adjust processing time (when water bath canning) or pressure (when pressure canning) for your altitude. Once jars have cooled for 24 hours, check the seals before storing in the pantry. Sterilize jars and tools by boiling when using a water bath canner, or use a pressure canner. Adding Thickener Prevents proper heat penetration and can result in undercooked foods. Do not add thickener to recipes. In tested recipes calling for thickener, use the type and the amount called for. Using the oven method Air is not a sufficient conductor of heat, leaving foods under-processed. This method can also cause jars to break or explode. Use canners designed specifically for the job, such as water bath canners or pressure canners. Do not use the oven method of canning. Using an Instant Pot to pressure can Instant Pots and multicookers are not properly calibrated for safe canning. Leave the Instant Pot for cooking and use a USDA-approved pressure canner for canning. Neglecting altitude adjustments Boiling temperatures differ according to altitude. Higher altitudes require more pounds of pressure for pressure canning, and water bath canning requires extended processing time. Know your altitude and adjust processing times accordingly. Neglecting a proper seal Improper seals can result from neglecting to wipe the rims of the jars before fastening the lid, and can cause food siphoning from overfilled jars or vacuuming from underfilled jars (including jars without air bubbles removed). Always fill jars following the recommended headspace, and use a plastic headspace ruler or wooden skewer to shift the foods on all four sides of the jar, releasing air bubbles prior to processing. Do not use a metal utensil as it will damage your jars, causing weak points prone to breakage. Before adding the lid, always wipe the rim with a clean, lint-free towel (or paper towel) dampened with water. Over-tightening lids If your bands are too tight, air will not properly vent from the jars, causing the lids to buckle and resulting in seal failure. Screw on the bands “finger-tip-tight,” meaning that you only use the tips of your fingers (not the palm of your hand) just until you reach the point of resistance.  Neglecting to vent the canner Venting distributes the heat evenly. Without it, the temperature will not reach the optimal temperature for safe processing. Your pressure canner needs to steam for a solid 10 minutes BEFORE you put that canning gauge on. Implementing this step has drastically diminished the number of botulism cases. Neglecting to have your gauge tested Untested gauges are untrustworthy and produce inconsistent results. Have your dial gauge tested annually at your local extension office. The workaround to getting your pressure gauge tested would be to use a weighted gauge pressure canner. This means your jiggler or weight determines the pressure and not a dial gauge. Neglecting to add acid to low-acid foods (like tomato products) Foods such as tomatoes generally do not have a high enough acid level to prevent botulism from growing. Follow approved recipes, and do not skip or reduce the acid ingredients. Attempting to speed up cooling time Approved recipes depend on cool-down time as part of the cooking process. If this is sped up, the foods will be underprocessed, leading to potential botulism growth.  Water Bath Method: Turn the heat off, remove the water bath canner lid, and let the jars sit for 5 minutes.
Pressure Canner Method: Once the pressure has dropped back down to zero naturally, remove the canner lid and let the jars sit for 5 minutes before removing the jars. NEVER run your hot canner under water. This could additionally cause jars to break. Place hot jars on a towel to cool for 16 to 24 hours undisturbed. Allowing “hot pack” foods to cool Hot pack processing relies on the food to remain hot. If the hot pack items cool between steps, they will be undercooked and prone to botulism growth. Move quickly, and work in batches to keep hot pack items at the right temperature before processing in the canner. Neglecting to remove bands prior to storage. Leaving the bands on can create a “false seal,” preventing you from properly inspecting your preserves before storing them. Remove bands once your jars have cooled. If you have space, it’s recommended to store your jars in a single layer. However, if you need to stack jars for space reasons, just be sure you put something like a layer of cardboard in between the jars so the weight of the jar is not on the center of that lower jar lid, causing a potential false seal. Substituting fresh lemon juice for bottled Bottled lemon juice provides a consistent acid level suitable for safe canning, whereas fresh lemons vary in their acidity levels. Always use bottled lemon juice unless an approved canning recipe specifically instructs to use fresh lemon juice. In this case, the recipe is relying on lemon juice for flavor instead of acid. Improper ratios of vegetables in salsas Increasing onions, peppers, or other vegetables can throw off the acidity ratio, resulting in possible botulism poisoning. Follow the exact measurements indicated in the approved recipes.