Combine the ingredients of the brine and mix or stir very well. The brown sugar and salt will dissolve.
Place the tuna steaks in the brine and put in the refrigerator for up to 3 hours.
Remove the tuna from the brine and pat dry to remove as much water as you can. You do not need to rinse the tuna but I do suggest it for anyone that is sensitive to salt. Rinse if you have any questions at all.
Set the smoker to 225-250°.
Add tuna steaks and smoke for 60-90 minutes or until it is 135-140°. If it gets much higher than that, it will dry out.
Storage: Just a couple days in the refrigerator or you can put them in a freezer safe bag for up to three months. We like to double wrap them to protect our food as much as possible. Food Sticking to Grill Grate: All foods can stick to the grill if they are not oiled before putting food on the grate.Internal Temperature: Use your wireless or instant probe thermometer to check for the temp to reach 135-140°. Always use a thermometer when testing when tuna is fully cooked. There is a lot in play with this one as the thickness and the fluctuations of the temperature of the smoker.Rinsing Tuna: Rinse the tuna after brining it if you are sensitive to salt at all. If you question whether you are, just rinse it off and pat it dry. It is not a salty recipe but I don't want anyone to ruin a recipe and have to toss it because it was too salty.