"STEP BY STEP INSTRUCTION ON HOW TO CAN TUNA"

Buy some Fresh Albacore Loins (boneless skinless tuna fillets) from a reputable health approved facility such as Giovanni's Fish Market. (You can use any kind of Tuna or even Salmon for that matter!)
Purchase desired size jars with lids and rings ( ½ pint or Pint Jars are good 1-2 serving size) Available at most hardware stores or online. They also sell pressure cookers if you don't have one. Do yourself a favor, and buy the largest you can afford, this will speed up the somewhat lengthy process, by enabling you to do more jars at once, My 23 qt. Presto holds 2 layers of 8 pints each for a total of 16 Pints per batch. I prefer the PINT WIDE MOUTH jars, they fit albacore chunks perfectly, and holds just enough tuna to make a couple tuna sandwiches).

STEP 1
Cut your loin into "log size" pieces about 2.5 inches in diameter by 3.5 inches long just enough to fill the jar edge to edge and leave 1 inch of space at the top of the jar, this is known as "Headspace" and is VERY Important for a good seal.

STEP 2
Sanitize the Jars, rings, and lids. You can do this one of two ways either by running through the dishwasher on the hottest cycle possible, (without soap), Or hand-wash all items in hot soapy water, then transfer your (wet) jars to an oven and heat to 325 for at least 20 minutes.. For the Lids & Rings, I just simmer (Do Not Boil) them in a small pot of water on the stove

STEP3
Pull the Jars from the oven, and line up jars in rows. I splash about an ounce of olive oil in the bottom of each jar to begin. Next, Place the chunk of fish (as described above) into each jar avoiding as many air pockets around the fish as possible, (Fill the voids with smaller pieces of fish if necessary). Remember leave 1 inch of Space from the top of the jar ( This is VERY important or your jars will overflow and will NOT seal!) Now sprinkle a 1/4 tsp of Kosher salt on top of the fish in each jar. Next Add a couple ounces of Olive Oil (or water) to fill in the air gaps that might remain. Now you have jars with Fish, olive oil, and Salt.

STEP 4
Next take a hot, damp CLEAN towel, and wipe the rim of every jar to clean any debris from the salt or fish that may be hanging on the rim. This step is also very important, on tiny piece of matter on the rim will prevent your jar from sealing. And the fish will NOT be shelf stable. When all the rims are perfectly clean on the top. Take the lids out of the hot water, and place a lid on top of each jar and screw a ring on the jar, just past loose (not quite snug) Do not tighten the ring down! Remember always use NEW Lids! NEVER Re-Use a LID for future canning, Rings and jars are reusable, but lids are NOT!

STEP 5
Add about 2 inches of water in the bottom of your pressure cooker and turn the heat up. Place the jars in a circle at the bottom of the pressure cooker (there should be a spacer that sits on the bottom of the pan). Place them in a circle so you can fit 6-8 in the bottom of the cooker or as many as you can fit. Then place another row on top of the bottom row, You can buy a spacer to go between the 2 layers online, it's recommended but not required. Depending on jar size and cooker size you may be able to do a third row on top of that (This is why we buy the 23 Qt. cooker...) The bottom jars will be partially submerged in water; this is OK.

STEP 6
Now follow the directions for putting the lid on your cooker, and make sure it is securely locked in place. There are several styles of cooker gauges; some have a weighted gauge that rattles when up to temp/pressure. Others have a dial gauge that shows how many pounds of pressure, some both. The desired pressure is 10-15 pounds, (depending on your elevation) Once you reach the correct pressure turn down the heat to about 1/3 or so that the pressure remains constant. On the rocking weighted gauges, they will make a swishing air noise and rock around on top, adjust the heat so that it rocks at a constant slow speed, not furiously rocking, but not too slow just a nice even shake and hiss. Now is the time to set you timer for 90 minutes. ( This is Important !) Start your timer when the cooker reaches the Correct Pressure (10 lbs. at sea level, it's about 15 pounds at 1500 ft elevation) or until the rocker is slowly rocking.

STEP 7
After 90 MIN Turn OFF HEAT and let it set, it will continue to cook, and will take some time to cool down enough to remove the lid (Maybe an hour OR MORE, after heat is off.) NEVER try to take the lid or rocker off while there is any pressure in the cooker this is Extremely dangerous! Once the pressure is gone (Zero Pounds), there is usually a little button that pops down on the lid to let you know the pressure has all escaped. Now you can safely remove the lid; be careful some steam will still be coming out. Use a jar lifter or a pair of hot mittens to remove the jars one at a time (again these will be very hot) set them on a towel on a table and let them sit not touching each other. They will continue to boil for some time in the jars, and will have produced some MORE liquid inside. Listen for the lids to "snap" or "Ping" this happens as a result from the vacuum that is created, This is a good indication that your jars are successfully sealing your jar. (Be patient this process can take up to 8 hours for the jar to ping or seal) DO NOT attempt to push or force it down it just takes time. Some will seal quickly, within a few seconds or a few minutes and some will be stubborn and take hours, and some will not seal, these that do not seal within 8 hours are still good too eat, but are NOT shelf stable, and must be refrigerated. ** After 24 hours check ALL lids for tight seal by gentle pulling on the lids (Rings removed) If the lid easily comes off the seal failed and is NOT SHELF STABLE. True Seals will be Difficult to remove by hand. You can store with or without rings, but I prefer WITHOUT to prevent a "False Seal" a sealed lid will stay sealed without the need of a ring if done correctly!

STEP 8
Well that's it once they are cool, wipe off any residue on the glass from the steam and such, you can even wash them in soapy water to remove any siphoned fish material. Put them in you cupboard and store for up to a few years. Once you try home-canned tuna I guarantee you will NEVER buy a can of tuna in the grocery store again... Also, for a special twist try adding different herbs or spices on top of the tuna before you put the lid on, anything you put in that jar will infuse into the tuna for a totally new taste!

Below are some of my personal favorites:

Garlic Cloves
Fresh Thyme or Rosemary
½ jalapeno (seeds and pith removed -- or not..)
Hot Sauce, Pepper Flakes, or Cracked Pepper

Or mix and match ! Like "Garlic-Rosemary"

Finally, take a Sharpie and write on the lids what's inside: "Tuna w/ Rosemary"
Good luck and happy canning, feel free to call me anytime for pointers

IMPORTANT NOTE REGARDING CANNING :
https://nchfp.uga.edu/questions/FAQ_canning.html
https://www.cdc.gov/foodsafety/communication/home-canning-and-botulism.html