How to make the perfect french fry, according to science

The key is a crispy exterior and a soft interior.

There’s nothing quite like a perfect french fry. It’s that magic combination: crispy on the outside, pillowy on the inside, and just the right amount of seasoning. What happens during the cooking process that turns the humble potato into a tasty treat? Celebrity chef Jet Tila and food scientist Dr. Arielle Johnson break down the recipe and science of french fries that you can make at home.

Double-Fried French Fries with Garlic Aioli

Adapted from “101 Epic Dishes” by Jet and Ali Tila © Page Street Publishing 2019. All rights reserved.


Garlic Aioli

  • 2–3 peeled garlic cloves minced
  • Salt and pepper, to taste, divided
  • 2 egg yolks, separated
  • 1 cup (240 ml) extra virgin olive oil, divided
  • 1 tablespoon (15 ml) fresh lemon juice


  • 4 medium cloves garlic, finely minced
  • About 1⁄4 cup (10 g) total of chopped fresh herbs (such as parsley, sage, rosemary and thyme)
  • 2 tbsp (6 g) minced chives
  • 3 large russet or Kennebec potatoes (about 21⁄2 lb [1.1 kg])
  • Pan spray
  • Vegetable oil, for deep-frying
  • Kosher salt, to taste


  1. To make the aioli, place the garlic in a blender with a large pinch of kosher salt and ground pepper. Pulse 3 to 4 times to finely mince the garlic.

  2. Add the egg yolks and run the blender for about 2 to 3 seconds until the yolks are whipped and creamy yellow in color. With the blender running on low, slowly pour in half of the olive oil in a tiny stream. Add the lemon juice. Gradually stream in the remaining olive oil and process until the mixture thickens and emulsifies. Transfer to a small bowl; add salt, pepper, and any other seasonings of choice. Cover and chill well.

  3. Fill a medium-size bowl with cool tap water. In a large bowl, combine the garlic, herbs and chives.

  4. Wash the potato skins well. We like to leave the peel on, but you don’t have to. Coat a knife with a bit of pan spray to keep it from sticking to the potato. Cut a 3⁄8-inch (1-cm) slice off one side of the potato. Place the potato on this flat side and cut the rest of the potato into 1⁄4-inch (6-mm) tiles. Stack the tiles and cut into 1⁄4-inch (6-mm) lengths. This French fry shape is called a batonnet in the French kitchen.

  5. Immediately place the batonnets into the bowl with cool water. The excess potato starch will be rinsed away. After all the fries have been rinsed, line a rimmed baking sheet with paper towels and transfer the fries to the tray. Use more towels to blot water from the top.

  6. Set up a deep fryer with about 5 inches (12.5 cm) of oil and heat the oil to 325°F (170°C). An enamel-coated cast-iron fryer is a great choice for this, if available. Carefully use a spider to add the fries to the oil in small batches. This first fry helps create a thin crust on each fry and precooks the center. Fry for about 5 minutes. They’ll still look quite pale. Have a pan with a rack to allow to drain and cool. Let the oil temperature recover to 325°F (170°C) before dropping in the next batch.

  7. When ready to eat, heat the oil to 365°F (185°C). Drop in the fries in small batches using a spider. When the fries turn golden brown, after about 4 minutes, use the spider to gather the fries, allow to drain for a moment, then toss in the bowl with the garlic mixture. Season with salt and serve immediately with the garlic aioli.

For more, check out the video, above. You can also subscribe to Popular Science on YouTube?