Purpose: Heat distribution studies in ASC compared to BWC allow for a determination of come-up time in both canner types. Such information is critical in establishing safe-use instructions for consumers wishing to use this new type of canner.
Methods: Recording thermocouples were inserted in three locations in the top of each canner. Tomato juice, room temperature (75°F) or preheated to 180°F, was packed into three different jar sizes: quarts (QT), pints (PT), and half-pints (HP), and the time for the heating medium to reach the processing temperature was recorded. Come-up time was the time that it took for the temperature of the heating medium (water or steam) to reach the processing temperature, 211 + 1°F or 100°C, starting with room temperature water (77 + 2°F) or pre-heated water (180°F), for atmospheric or boiling water canners, respectively.
Results: The time for the ASC to reach the process temperature ranged from 10.3-16.2 min across jar size and juice temperature. The time for the BWC to reach the process temperature, from the preheat temperature (180°F), ranged from 4.3-21 min across jar size and juice temperature. When preheat temperature was included in come-up time, BWC processing time ranged from 23-49 min.
Significance: Home food preservation can be an enjoyable but resource intensive process. The preheat time can be a lengthy component of a BWC process and may discourage consumers from following proper canning methods. Consumers who fail to completely follow a research-tested, up-to-date recipe put the health of their family at risk. ASC may offer a convenient method for preserving low pH foods and enables consumers to adopt appropriate food preservation practices.