Home Canning - Selecting The Correct Processing Time

What You'll Need
USDA Complete Guide to Home Canning, 2015 Revision
Canning Jars and lids
Boiling water-canner or pressure canner
Stove top compatible with canner being used
Foods appropriately prepared for canning process
Water
Canner Jar Lifter
Kitchen Towels and paper towels

Best methods for Home Canning from the Cooperative State Research, Education and Extension Service, U.S. Department of Agriculture (CSREES-USDA)

When canning in boiling water, more processing time is needed for most raw-packed foods and for quart jars than is needed for hot-packed foods and pint jars.

To destroy microorganisms in acid foods processed in a boiling-water canner, you must:

1. Process jars for the correct number of minutes in boiling water.

2. Cool the jars at room temperature.

The food may spoil if you fail to add process time for lower boiling-water temperatures at altitudes above 1,000 feet, process for fewer minutes than specified, or cool jars in cold water.

To destroy microorganisms in low-acid foods processed with a pressure canner, you must:

1. Process the jars using the correct time and pressure specified for your altitude.

2. Allow canner to cool at room temperature until it is completely depressurized.

The food may spoil if you fail to select the proper process times for specific altitudes, process at lower pressure than specified, process for fewer minutes than specified, or cool the canner with water.

Warning: Improper canning techniques can lead to foodborne illness contamination of canned foods, specifically botulism.

Using Tables for Determining Proper Process Times

The set of guides includes processing times with altitude adjustments for each product. Choose the canner pressure you wish to use and match it with your pack style (raw or hot) and jar size to find the correct process time. The following examples show how to select the proper process for each type of canner Process times are given in separate tables for sterilizing jars in boiling-water, dial-gauge, and weighted-gauge canners.

Example A

Suppose you are canning peaches as a hot-pack in quarts at 2,500 ft above sea level, using a boiling-water canner. First, select the process table for the type of canner to be used (boiling-water canner). The example for peaches is given below. From Table 1, select the process time given for (1) the style of pack (hot), (2) the jar size (quarts), and (3) the altitude where you live (2,500 ft). You should have selected a process time of 30 minutes.

Example B

Suppose you are canning peaches as a hot-pack in quarts at 2,500 ft above sea level, using a dial-gauge pressure canner. First, select the process table for the type of canner to be used (dial-gauge canner). The example for peaches is given below. From Table 2, select the process pressure (PSI) given for (1) the style of pack (hot), (2) the jar size (quarts), (3) the process time (10 minutes), (4) the altitude where you live (2,500 ft). You should have selected a pressure of 7 lbs for the 10 minutes process time.

Example C

Suppose you are canning peaches as a hot-pack in quarts at 2,500 ft above sea level, using a weighted-gauge pressure canner. First, select the process time for the type of canner to be used (weighted-gauge pressure canner). The example for peaches is given below. From Table 3, select the process pressure (PSI) given for (1) the style of pack (hot), (2) the jar size (quarts), (3) the process time (10 minutes), and (4) the altitude where you live (2,500 ft). You should have selected a pressure of 10 lbs for the 10 minutes process time.

Table 1

Table 1. Recommended process time for peaches in a boiling water canner
Process Time at Altitudes of
Style of Pack Jar Size 0 - 1,000 ft 1,001 - 3,000 ft 3,001 - 6,000 ft Above 6,000 ft
Hot Pints 20 min 25 min 30 min 35 min
Quarts 25 30 35 40
Raw Pints 25 30 35 40
Quarts 30 35 40 45

Table 2

Table 2. Recommended process time for Peaches in a dial-gauge pressure canner.
Canner Pressure (PSI) at Altitudes of
Style of Pack Jar Size Process Time 0 - 2,000 ft 2,001 - 4,000 ft 4,001 - 6,000 ft 6,001 - 8,000 ft
Hot and Raw Pints or Quarts 10 min 6 lb 7 lb 8 lb 9 lb

Table 3

Table 3. Recommended process time for Peaches in a weighted-gauge pressure canner.
Canner Pressure (PSI) at Altitudes of
Style of Pack Jar Size Process Time 0 - 1,000 ft Above 1,000 ft
Hot and Raw Pints or Quarts 10 min 5 lb 10 lb

Extracted from the "USDA Complete Guide to Home Canning, 2015 Revision"

Courtesy of the National Center for Home Preservation, funded partially by

NIFA’S National Integrated Food Safety Initiative