Tuna may be canned either pre-cooked (bake/steam) or raw. If you pre-cook it, you will need to add water or oil to jars, leaving 1-inch headspace. You do not add any liquid to the jars if you process raw tuna. You may add ½ teaspoon of salt per half-pint or 1 teaspoon of salt per pint, if desired. In place of the salt you may choose to use powdered chicken bouillon, or add garlic or jalapenos; it depends on your personal taste. Consider using vinegar in place of water on a paper towel when cleaning the jar rims, then wipe with a dry paper towel. This helps to remove any fish oil prior to placing the jar lids to ensure a good seal. Process tuna in a Dial Gauge Pressure Canner at 11 pounds of pressure OR in a Weighted Gauge Canner at 10 pounds of pressure. Both half-pint and pint jars are processed for 100 minutes.
WSU has a great publication titled, PNW 194 Canning Seafood. If you don’t have the manual for your pressure canner, you may want to read/print, PNW421 Using and Caring for Your Pressure Canner. Both publications can be downloaded or purchased directly from WSU Extension Publications at: https://pubs.extension.wsu.edu/.
Newer jar lids no longer need to be simmered. Manufacturers are using a new compound so washing the lids in warm soapy water will suffice. Rinse and dry the lids before placing on the jars.
This information was originally posted by C. Koehler on the WSU Grays Harbor County Extension website.