The pressure required for pressure canning changes with altitude, so one setting does not work everywhere. With a weighted-gauge canner, use 10 psi from sea level through 305 meters and 15 psi above 305 meters. A dial-gauge canner has finer increments, with pressure increasing by one step at 610, 1,219, and 1,829 meters. The processing time stays the same; the pressure changes.
As altitude increases, air pressure decreases, and water’s boiling point drops with it. The temperature inside a pressure canner is directly tied to pressure, so the same gauge reading produces a different temperature at different altitudes. A setting that reaches the target at sea level can leave the center of the same jar a few °C cooler in a high-altitude city. In canning, those few °C can determine whether processing is complete. That is why altitude is not a minor detail; it is the basis of the chart. The same recipe, jar, and processing time can produce a different result at a different altitude.
A weighted-gauge canner has 2 pressure settings, with no in-between option. Use 10 psi through 305 meters above sea level, and 15 psi above 305 meters. Once the weight reaches the set pressure, it rocks at regular intervals and releases excess pressure on its own. Your job is to adjust the burner so the rocking remains regular. You cannot choose an intermediate setting because the weight itself is fixed. This makes the method easier: use the heavier weight once the altitude threshold is exceeded.
A dial-gauge canner shows pressure with a needle, allowing finer adjustments. Use 11 psi up to 610 meters above sea level, 12 psi from 610 to 1,219 meters, 13 psi from 1,219 to 1,829 meters, and 14 psi from 1,829 to 2,438 meters. Adjust the burner continuously while watching the needle. If the pressure drops, restart the processing time from the beginning. If the needle is inaccurate, the entire chart is invalid, so have a dial gauge checked every season. The needle moves as the burner cycles on and off, which means you need to stay nearby while using a dial-gauge canner.
This chart matters in Türkiye because the country spans 3 distinct altitude bands. İstanbul and İzmir fall in the first band, where 10 psi is sufficient with a weighted-gauge canner. Ankara is at 938 meters and falls in the second band; Konya is above 1,000 meters. Erzurum is above the 1,829-meter threshold and falls in the highest dial-gauge setting. The same recipe, jar, and processing time require 3 different pressure settings in these 3 cities. If you do not know the altitude, check the published official figure for the province or district.
Altitude changes pressure, not processing time. The processing minutes listed in the canning chart stay the same at every altitude; at higher elevations, hold the canner at a higher pressure to maintain the temperature at the center. Do not confuse this with the boiling-water-bath rule: there is no pressure in that method, and altitude compensation is added to the processing time. The 2 methods have 2 separate adjustments, and one does not replace the other. Do not use the boiling-water-bath processing time for pressure canning or the pressure-canner psi setting for a boiling-water bath. Post the value from the chart in the kitchen and consult it for every canning session.