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WATER BATH CANNING: PROCESSING TIME

Once you have prepared your ingredients, filled the clean jars with your high acid preserve, and then added the lids/seals, jars will require processing in a water bath canner prior to pantry storage, as per the recipe. Processing refers to submerging jars in water and boiling for a specific length of time. There are different times for jar sizes, different times for types of preserves, and adjustments for altitude if required.
 
Jar size options for water bath canning recipes are:
o  Less than or equal to 500ml – i.e. pint/16oz jars – these require shorter processing time than larger jars because they heat up quicker (less volume of food in each jar);
o  500ml to 1 litre – i.e. quart/32oz jars – these require a longer processing time than smaller jars because they need more time to heat up (they have a higher volume of food in each jar).
Note: some recipes list just the maximum jar size i.e. up to 1 litre/quart (or less) for the processing time in the recipe chart.
  
Water bath canning recipes are either “cold packed” – which is also known as raw-packed (i.e. raw, prepared fruit or vegetables) - or hot-packed (i.e. jam or chutney). How food is prepared (and the density) determines the minimum processing time required.
o  Raw packed food requires longer processing time than hot packed food as the food takes longer to come to the temperature required to destroy microorganisms, and also requires cooking prior to pantry storage;
o  Hot-packed food requires a shorter processing time than raw packed food because the food has already been heated/cooked to a high temperature and just requires the pasteurisation stage via a water bath canner prior to pantry storage. Example of a processing chart below:

Processing Time for BOTTLED PEACHES (HALVED OR SLICED) in a Boiling Water Canner
 
Jar Size
Altitude
1,000 feet
Altitude 1,001
- 3,000 feet
Altitude 3,001
- 6,000 feet
Altitude
6,000 feet
Hot
Pack
500ml (pints)
20 minutes
25 minutes
30 minutes
35 minutes
1 Litre (quarts)
25 minutes
30 minutes
35 minutes
40 minutes
Raw Pack
500ml (pints)
25 minutes
30 minutes
35 minutes
40 minutes
1 Litre (quarts)
30 minutes
35 minutes
40 minutes
45 minutes

Water also boils at different temperatures – the higher the altitude, the lower the temperature required for water to boil. Therefore, a longer processing time is required when altitude increases.
 
To ensure high acid food is preserved in a water bath canner accurately, the processing time and cooling down period (i.e. 12-24 hours at room temperature) must be followed, as per the recipe. Choosing the correct processing time and allowing jars to naturally cool down at room temperature is the best way to destroy microorganisms such as mould and yeast that could otherwise spoil your preserves.
 
Author: Megan Radaich           
Image Credit: Megan Radaich            
Publication: www.foodpreserving.org

Acknowledgement 
Kaya Wanjoo. Food Preserving kaditj kalyakoorl moondang-ak kaaradj midi boodjar-ak nyininy, yakka wer waabiny, Noongar moort. Ngala kaditj baalap kalyakoorl nidja boodjar wer kep kaaradjiny, baalap moorditj nidja yaakiny-ak wer moorditj moort wer kaditj Birdiya wer yeyi.
Hello and Welcome. Food Preserving acknowledges the Traditional Custodians of the land on which we live, work and play, the Nyoongar people. We recognise their connection to the land and local waterways, their resilience and commitment to community and pay our respect to Elders past and present.
 
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