Unfortunately, many home food preservers check on their canning methods a day or even a couple weeks after they have canned. And, the after-the-fact calls to the Cooperative Extension about processing sometimes yield the very sad news that none of the canned fish will be safe to eat.
Prepare to make it safe. If your pressure canner has a dial gauge, make it a habit to have the gauge checked annually before you begin processing. These can be checked at your local Extension office. Next, review recommended processing times and methods in Extension’s current publications. In my many classes over the past 11 years, I have found that many people are still using older and unsafe processing times. Improperly canned or jarred fish or other low-acid foods (meat and vegetables) may contain the potentially fatal botulinum clostridium toxin, so it is important to get it right.
To avoid under-processing, use the following times and instructions for canning salmon. More detailed instructions for canning can be found in Extension’s “Canning the Catch” publication, which is available online.
Processing: Add 2 to 3 inches (about 3 quarts) of cool water to the pressure canner. Put the rack in the bottom of canner. Place closed jars on the rack, according to the instructions with your pressure canner. Fasten the canner cover securely, but do not close the lid vent.
Heat the canner until steam comes through the open vent in a steady stream. Allow the steam to escape for 10 minutes. This step removes air from inside the canner and creates an even temperature in the canner.
Turn the heat on high until the pressure gauge reads 11 pounds per square inch (psi) on the dial gauge or the 10-pound weighted gauge begins to jiggle, and then adjust the heat to maintain a steady pressure and begin timing the process. If the pressure drops below 10 or 11 psi, bring it back up to the correct pressure and begin timing from the beginning (100 minutes) over again. If the pressure rises above 10 or 11 psi, lower the heat but do not begin timing again.
The following is recommended for jars of fish:
• Use 10 pounds pressure for a weighted gauge and 11 pounds pressure for a dial gauge. For ½-pint jars, process for 100 minutes also using the same pressures recommended above.
Don’t wait to get your pressure canner gauges checked
For safety’s sake, you must have a complete, uninterrupted 100 minutes at a minimum pressure of 11 pounds for a dial gauge or 10 pounds for a weighted gauge. Dial gauges should be checked annually to make sure that they are properly calibrated.
At the end of the processing time, slide the canner away from the heat so it can cool. Let the pressure drop to zero psi naturally. The cooling should not be rushed as this is part of the safe processing time.
Carefully remove jars with a jar lifter or tongs and place on a cooling rack or insulated surface away from drafts. Do not tighten lid rings. The sealing compound is hot and soft and the jar lids are still sealing.
After 12 hours, the jar lids should be sealed — the lids curve downward in the middle and do not move when pressed with a finger. Lid rings are not needed on stored jars; you may remove them. Wash and store for later use.
If a jar did not seal — the lid bulges or does not curve downward in the center and moves when pressed with a finger — remove the lid and check the jar sealing edge for tiny nicks. If needed, change the jar, add a new, properly prepared lid, and reprocess within 24 hours using the same processing time.
Leslie Shallcross is the Tanana District health, home and family development agent for Cooperative Extension Service, a part of the University of Alaska Fairbanks, working in cooperation with the U.S. Department of Agriculture. She can be reached at (907)474-2426 or firstname.lastname@example.org.