Why are hot and raw pack processing times sometimes the same?
Hot pack and raw pack variations, as presented on pickyourown.org are derived from USDA recommendations, which have each been researched separately by the USDA. This includes collecting heat penetration data and calculating an independent process time for each. So the process time is determined by the actual heating characteristics of the pack. Depending on preparation procedures and the type of process, the final result may be the same. Other times, it might be different. The temperature of the process (boiling water or pressure) and the length of the process needed can influence the differences between hot and rack pack rates of heating. Another consideration is that USDA home-canning processes are rounded off to the next higher 5-minute interval. If the hot and raw pack process times vary by less than 5 minutes, but in the same interval, the recommended process time will be the same. For example, if the hot pack is calculated as 11 minutes and the raw pack requires 14 minutes, they
