Pint and Half-Pint Processing

• Jars of high acid foods are processed in a boiling water canner to prevent the growth of mold and enzymatic damage during storage. Because they are smaller, you can substitute half-pint jars for pints with no change to processing time. However, going the other way from half-pints into pints, it will take more time for the heat to penetrate the jar and heat it to the necessary level to destroy spoilage organisms and therefore the processing time will need to be adjusted.

Adjusting Times

• When you are processing different-sized jars, it is important that you adjust processing time for the largest size of jar. While this may create a slight over-processing in some products, the difference between pint and half-pint jars is typically only a matter of minutes and should not greatly affect the outcome. If your recipe has processing times for both pints and half-pints, then simply select the processing time for the pints. However, if there is no processing time stated for pints, consult with the U.S. Department of Agriculture or the National Center for Home Food Preservation to determine the appropriate processing time for your product.

Keep Them Covered

• When processing different-sized jars, it is important that you cover the tallest of the jars with at least 1 inch of water to create an adequate seal on your jars. Ensure that you do not overcrowd the jars in the canner so that the hot water is able to circulate around your jars and evenly heat them. Once you have added all your jars to the canner, cover its lid, return it to a boil and set your timer for the indicated processing time.

Canning Safety

• Boiling water canning is only recommended for high acid foods such as jams, jellies, pickles and salsas. Because these foods all have a pH lower than 4.6, they are not susceptible to growth of the deadly clostridium botulinum toxin. However, they are all susceptible to mold growth and therefore, it is important to follow a tested canning recipe from a reputable source to ensure its safety. While it is safe to use pint and half-pint jars together in a recipe, if the recipe is unsafe to begin with, jar size makes little difference as far as your safety.