I did a large batch of mostly Speckled trout this week in Canola oil outside on the propane cooker. It was super good and everyone was getting second helpings and raving about it. I really like doing fish in a cast iron skillet inside if itís just a couple of folks, but when cooking for more than 3-4 people, I move the operation outside and use the propane set up. I have a heavier gauge large aluminum pot that isnít too deep with a temperature gauge that clips off the side.
You might be surprised how much the temperature changes or wants to change if you arenít using a temperature gauge. The temperature can dip or spike pretty rapidly even if I donít crowd the fish. I really stay on top of the gas control and do almost constant adjustments for the best results. A heavy cast iron vessel would probably dampen the temperature swings, but on the other hand aluminum is very responsive to gas input adjustments. Aluminum can be managed, but it needs nurturing. After doing this for years, Iíd say the idea is to keep the fish between 325-360 degrees at least with Canola oil. 340-350 degrees is my target, but brief dips to 325 or short spikes about 360-370 doesnít seem to hurt things. That temperature range produces the best flavor and crispness in my experience with a corn meal batter. If the temperature moves too much towards 400 degrees, a little burnt taste seems to creep in. A little too low on the temperature and then the fish wonít have quite as nice crisp exterior it could have and the good color.
I pull the fish when the bubbling just starts to subside and the fish is just beginning to float and the color of the crust looks right. The fish keeps cooking for a time after it gets taken out of the oil. The time to pull happens faster than you think. I try to keep the fish the same thickness which usually means splitting thicker portions of the fillets from bigger fish. it depends on how thick the fish was. About a half of an inch or maybe just a hair thicker is the max thickness. An inch is too thick in my experience. The tail pieces are obviously thinner. Everyone in my circle likes fried fish that isnít super thick and that is crisp, but not dried out. Thereís a short window to getting it right. I avoid going by time, but go on the bubbling and color. Thereís a tendency Iíve noticed at other fish fries Iíve attended that folks might go a little too long and almost completely dry out the fish. Iíve also been to fries where itís obvious the oil didnít stay hot enough. Iíve overcooked the fish at times and dried out the fish. Iíve been to great fries where the cook nailed it. When the temperature and time isnít quite right it doesnít mean the fish will be inedible, but maybe it wonít be as good as it could be. Iíve also been to fries where the temperature of the oil and/or the pulling time is so out of whack the fish was borderline inedible or pretty terrible. .
When I fry outside for a crowd, I sort of put on my game face and avoid distractions. I can visit after the cook. The temperature needs to stay in the safe range and the fish has to be pulled at the right moment. When people tell you how great the fish is the extra attention to details is worth it.