A Ball® jar full of pear butter on a wooden table with pears in the background

Fresh Preserving Troubleshooting

We want the fresh preserving process to be easy for you. The chart below details questions frequently asked by home canners. Based on our years of experience in the canning industry, our tips also comply with current USDA guidelines. We want to make sure your home preserved foods are the best they can be!

  • What happens if a seal fails?
    • Use food or refrigerate immediately. Only If the food was properly processed the first time, you may correct and reprocess if done within 24 hours. If an ingredient was left out, an ingredient was added, the wrong processing method was used, or the food was not processed long enough, you only have TWO hours to reprocess correctly.
  • What causes a seal to fail?
    • Failure to heat-process filled Ball® canning jars using the correct method and for the adequate amount of time.
      • Heat process all filled jars using the method and time recommended in a tested fresh preserving recipe for the specific food and jar size
    • Improper preparation of lids and/or improper adjustment of bands.
      • Carefully follow manufacturer’s guidelines for lids and bands.
      • Using your fingers, screw bands down until resistance is met, then increase to fingertip tight. Do not force. Do not use a lid wrench to apply bands.
    • Improper headspace.
      • Follow recipe for recommended headspace.
    • Food particles on jar rim.
      • Carefully clean jar rims and use a clean, damp cloth to remove residue before applying the lid and band.
    • Failure to adjust for altitude.
      • Adjust processing time/pressure for altitude.
  • What causes a false seal (appears sealed but later unseals)?
    • If spoilage is evident, do not use.
    • Inadequate vacuum caused by under processing or not heat processing filled jars.
      • Use the processing time and method recommended in the tested fresh preserving recipe.
    • Particles of food remain on sealing surface.
    • Crack or chip in jar rim.
      • Check jars before packing and discard any with uneven, chipped sealing surfaces.
    • Excess air left in the jar.
      • Use headspace recommended in recipe and slide a nonmetallic utensil between food and jar to release trapped air before applying lids and screw bands.
  • What causes the lid to buckle, warp, or bulge?
    • If spoilage is evident, do not use.
    • If visible immediately after processing, bands are too tight.
      • Make bands finger-tight. DO NOT force or use a lid wrench to apply bands.
    • If visible during storage, food has spoiled.
      • Use the processing time and method recommended in the tested fresh preserving recipe.
      • Adjust processing time/pressure for altitude.
      • Note: Foods on which lids buckle during storage must be discarded in a way that prevents consumption by both humans and animals.
  • What causes a loss of liquid during processing?
    • Food not heated before canning.
    • Food packed too tightly.
      • Pack food loosely when using the hot pack method.
    • Air bubbles not removed before lids and bands applied.
      • Use a Ball Bubble Freer to release air bubbles and measure headspace.
      • Slide a nonmetallic utensil between food and jar to release trapped air. Repeat 2 to 3 times.
    • Bands applied too loosely.
      • Make bands finger-tight. DO NOT force or use a lid wrench to apply bands.
    • Pressure canner not operating correctly.
      • Continuously regulate heat to maintain consistent pressure. Avoid sudden changes in the heat level.
    • Starchy foods absorb the liquid.
      • Pack all starchy foods loosely.
  • Why is liquid lost immediately after processing?
    • Jars removed from canner before the internal temperature stabilizes to room temperature.
      • For boiling water canner, remove the lid and turn the heat off. Before removing jars, wait 5 minutes.
      • For pressure canner, follow manufacturer’s cooling directions prior to removing canner lid. Before removing jars, wait 10 minutes.
  • What causes food to darken in the top of the jar?
    • The liquid did not cover food.
      • Completely cover food solids with liquid, making sure headspace is adequate, before applying closures.
    • Failure to heat process correctly.
      • Heat process all filled jars using the method and time recommended in a tested fresh preserving recipe for the specific food and jar size.
    • Incorrect packing and processing.
      • Use the processing time and method recommended in the fresh preserving recipe.
      • Use the hot pack method when indicated in recipe. Heat process all filled jars using the method and time recommended in a tested fresh preserving recipe for the specific food and jar size.
    • Excess air sealed in jar.
  • What causes food to discolor?
    • Natural chemical substances (tannins, sulfur compounds, and acids) in food react with minerals in water or with metal containers or utensils used in preparing the food.
      • Use soft water.
      • Use stainless steel cooking pans, stainless steel or glass bowls, and heat resistant nonmetallic utensils. Avoid using brass, copper, iron, aluminum, zinc or chipped enamelware.
  • What causes black spots to appear on the underside of metal lids?
    • Natural compounds in some foods cause brown or black deposits on the underside of the lid. This deposit is harmless and does not mean the food is unsafe to eat.
  • What causes rust to form on the underside of metal lids?
    • Improper coating or scratches on the underside of the lid.
      • Use lids distributed by an established manufacturer.
      • Use ONLY nonmetallic utensils when handling lids.

Download a printable version of Fresh Preserving Troubleshooting here.