Fries and frozen fries, pre-blanched to various temperatures. Notice how dark the un-blanched fries are due to excess sugars browning.
2 pounds russet potatoes (about 4 large), peeled and cut into 1/4-inch by 1/4-inch fries (keep potatoes stored in a bowl of water) 2 tablespoons distilled white vinegar Kosher salt 2 quarts peanut oil
1. Place potatoes and vinegar in saucepan and add 2 quarts of water and 2 tablespoons of salt. Bring to a boil over high heat. Boil for 10 minutes. Potatoes should be fully tender, but not falling apart. Drain and spread on paper towel-lined rimmed baking sheet. Allow to dry for five minutes.
2. Meanwhile, heat oil in 5-quart Dutch oven or large wok over high heat to 400°F. Add 1/3 of fries to oil (oil temperature should drop to around 360°F). Cook for 50 seconds, agitating occasionally with wire mesh spider, then remove to second paper-towel lined rimmed baking sheet. Repeat with remaining potatoes (working in two more batches), allowing oil to return to 400°F after each addition. Allow potatoes to cool to room temperature, about 30 minutes. Continue with step 3, or for best results, freeze potatoes at least over night, or up to 2 months.
3. Return oil to 400°F over high heat. Fry half of potatoes until crisp and light golden brown, about 3 1/2 minutes, adjusting heat to maintain at around 360°F. Drain in a bowl lined with paper towels and season immediately with kosher salt. Cooked fries can be kept hot and crisp on a wire rack set on a sheet tray in a 200°F oven while second batch is cooked. Serve immediately.