Update: tried frozen fries straight from the bag vs. soaked in cold water for 30 mins
The soaked ones came out way crispier in my air fryer at 400 for 18 minutes, and my wife finally stopped asking why I bought the thing last month. Has anyone tried the same soak trick with sweet potato fries, or does that just turn them to mush?
Skip the soak and just buy better fries, because the cold water thing is mostly working because your fries were dry and cold going in, not because of some starch magic. Kenji did tests on this and the difference is small enough that most people couldn't taste it side by side. Sweet potatoes will just go limp either way since they have way less starch to work with.