Starch accumulating as sediment during shallow fry Since I was shown how to make tatsutaage (a particular type of Japanese fried chicken with grated ginger in the marinade), I've been tweaking things in the recipe here and there, and this week have arrived at one that produces results I'm very happy with. The only problem is that the starch I coat the chicken with before frying it is accumulating as a thin layer of sediment in the oil which after a while starts to smoke, forcing me to pause, dispose of the oil, wipe everything down, then begin the process from scratch to finish, making the whole process far more time consuming--not to mention impractical for serving big groups that require several batches.

Here's the gist of the process: chicken thighs are sliced into pieces roughly 25 sq. cm on the smooth outward face, and about 2 to 3 cm thick. These are marinaded for 2 to 3 hours in a blend of usukuchi, koikuchi, tamari, sake, mirin, and grated ginger. I place a cast-iron skillet on medium-high heat and put about 1.5 cm worth of light olive oil (dat higher smoke point), and when the oil reaches 120C, I start adding the chicken.

The chicken is tossed in tapioca flour and lightly shaken of excess, then placed in the skillet, flipped once, then removed when internal temperature reaches 74C and placed on a plate with paper to let extra oil drain off.

The issue is that because the starch isn't clumped together in any significant way, the excess coming off is not even visible in the oil until it accumulates at the bottom, by which point it has browned and shortly after, things start to smoke. I am confident it is not the oil I use, as I monitor temperature closely and use a significantly lower temperature for this shallow fry than I do for the deep fry method I initially used, which did not cause the oil to smoke.

Any suggestions for managing this that don't require me to stop everything in its tracks, clean up, and then wait for a cast iron skillet full of oil to get back up to temperature before I can finish a batch?
Its your temp. The high temp of your deep fryer is exactly why your starches are staying put. Why did you choose a cooler temp for your shallow frying?