There are a few secrets to making perfectly crispy French fries at home. The goal is to ensure that the center of the fries are fully cooked before the outsides get too brown. The way to achieve this is to cook the fries twice using a particular type of potato and oil.
Frying your fries two times might sound like a lot of work. However, if you want them light and crispy, that's what you have to do. Otherwise, they'll either be crispy but undercooked in the middle or just plain greasy and limp.
The Best Potatoes
High starch potatoes like Idaho potatoes (also called Russet potatoes) are best for French fries. This variety is denser and they have the least amount of moisture in them.
Avoid waxy potatoes, a category that includes any with red skin, new potatoes, and fingerling potatoes. These contain so much water that they will actually hollow out when you fry them because the water will evaporate.
Prepare the Potatoes
Before you begin preparing the potatoes, fill a large bowl with cold water and add a tablespoon of lemon juice. As soon as you cut the fries, you're going to transfer them to this bowl. Cut potatoes will start to discolor if they're exposed to oxygen for too long—even if they're in the water. (There's oxygen in water, after all.) But a little bit of acid in the water helps keep the potatoes nice and white.
- Peel the potatoes and remove any eyes.
- Square off the potato with your knife and slice it into 1/4-inch slabs. Cut each slab into 1/4-inch strips. The fries should be about 3 inches long. Transfer them to the cold water as you go.
- When the fries are cut, rinse them under cold water in the bowl until the water turns clear. The idea is to rinse off any excess starch.
- Add another tablespoon of lemon juice, and then a few cups of ice—enough to chill the water thoroughly. Transfer to the refrigerator to chill for about 30 minutes. This step prevents the outside of the french fries from getting too brown before the inside cooks all the way through.
The Best Oil
Refined peanut oil is the best oil to use for making french fries. You can also use canola or safflower oil. Additionally, restaurant fries are so crispy because, among other things, they use old oil continuously.
As oil heats up it breaks down—cooking oils with a high smoke point will break down more slowly—and that creates crispier fries. The general rule of thumb is that you can reuse frying oil three or four times, or for a total of six hours cooking time. It needs to be properly filtered and stored in an airtight container, preferably in the refrigerator or a cool, dark, dry place. However, it can degrade faster than that. Before moving the storage container, look for any separation in the oil and then give it a sniff test; if it smells off or acrid, don't use it.
The Double-Fry Method
When it comes to the actual cooking, you want to fry the french fries twice. The first round is at a lower temperature to cook the inside of the potato and the second time you'll use a higher temperature to make the fries golden brown and crispy.
You can use a home deep-fryer or just heat the oil in a Dutch oven. Use a candy or frying thermometer to monitor the oil's temperature; thermometers that clip onto the edge of the pot ensure it doesn't slide around.
- Drain the fries from the ice water bath and pat them dry with a clean kitchen towel. Adding wet potatoes to the hot oil could cause it to spatter. You're also going to want to set up a couple of sheet pans lined with thick paper (e.g., brown paper grocery bags) nearby.
- Heat the oil over medium-low heat to 325 F. Cook the potatoes in the oil for 6 to 8 minutes, or until they're soft and a slightly golden color.
- Remove the fries from the oil using a wire mesh skimmer (sometimes called a spider spoon) and transfer them to the paper-lined pans to drain. You can refrigerate them again until you're ready to use them, or at the very least let them stand at room temperature for 15 minutes. Remember to turn off the heat under the oil during this time.
- Now heat the oil to 375 F. Return the fries to the oil and cook for another 2 to 3 minutes or until the fries are golden brown and crispy. Drain on clean paper, then salt generously and serve right away.