Brine is crucial to add moisture to the tuna.
Mix all of the ingredients listed above into the water.
Stir vigorously to blend all those flavors together.
Bring the tuna brine back down to room temperature, and pour the mixture into a bowl or shallow pan.
Add the tuna, making sure it is submerged. (Make and add more brine if necessary.)
If you use a bowl rather than a pan, you can divide the tuna along with brine into zipper-style plastic bags for the next step.
Leave the pan uncovered and put it into your refrigerator.
Or take your plastic bags of marinating tuna and put them in your refrigerator.
Allow at least three hours for the tuna to marinate well.
Some people leave it in the refrigerator for six hours, or even overnight.
The original recipe I used called for six hours, but I found that a lot of the tuna flavor was lost with that length of time.
Three hours seemed to be just about perfect.
While the original recipe said to rinse the tuna before patting it dry, it just didn’t make sense to me to rinse off all of the good stuff I’d put in the brine.
So I patted the fish dry using paper towel, leaving on as much of the good flavorings as I could.
Once you’ve pat-dried the tuna, air dry it for one to two hours on a cold grill rack or similar stand.
You can speed up the drying process by putting the tuna in front of a fan, but make sure the meat doesn’t get too dried out.
Depending on your own environmental conditions even an hour of air-drying may be too much.
The goal is to let a good pellicle develop and stop there, so keep a close eye on that tuna.
The pellicle is the coating or skin on the surface of the tuna (or other meat) that allows smoke to adhere.
It’s useful in smoking any kind of meat, but is especially important for smoking fish.
The pellicle protects the meat from being over-smoked, but enhances the flavor and color from smoking.
Once you are satisfied that the pellicle is well formed but the tuna still somewhat moist, dredge the tuna in some more brown sugar.
It means to coat a moist food (such as marinated tuna) with a dry ingredient (such as brown sugar) prior to cooking.
In other words, simply roll the tuna through some brown sugar, making sure to coat each piece evenly.
Another recipe calls for fresh lemon juice, garlic powder, ground black peppers or other spices add subtle flavors, but really - it's all up to you!
Place the dredged pieces on racks, or directly on your grill.
The type of wood chips you're going to use depends on the type of smoke flavor you want to get.
Fruit wood like cherry wood usually isn't used for smoked fish, so you might wan to explore other options.
Smoke the meat at 175 degrees for 60 to 120 minutes.
If your thermometer tends to reflect a higher temperature than has usually really been achieved, move the temperature up to 190 degrees.
Larger cuts require more time.
Experiment with your own cuts and the time necessary to perfect each piece.
Check your temperature regularly to make sure you are staying in range.
You’ll notice a change in color to the tuna.
To be extra certain that your tuna is well-cooked, use a meat thermometer and look for a temperature at the midpoint of the meat of about 140 degrees.
Once you reach that, you can pull the tuna out of the smoker.
If you see a flakiness to your tuna, you’ve done a perfect job!