Why are french fries fried twice

Why double fry french fries after blanching instead of just blanching and frying them?

I love good fries. I've made them at home with some success using the Steak Fries recipe originally developed by Cooks Illustrated / America's Test Kitchen. In their recipe, cut potatoes are rinsed, soaked, fried at a lower temperature, then finished at a higher temperature. It wasn't about blanching, and research has shown me that blanching can help.

In another recipe I found for french fries cooked twice, they just get bleached and then fried. Will this technique make good fries?

According to Serious Eats, McDonald's french fries are bleached and fried at a lower temperature, frozen and finally fried before being served to you.

The French culinary institute has a technique of pre-leafing, puffing, freezing and then frying twice - talk about the work!

From what I've read, pectin is released during blanching at certain temperatures. Blanching also removes some outside starches that I assume can be achieved by rinsing and soaking. If you are blanching in salted water, pre-salt the fries.

My question is, what is this initial lower temperature roast doing? Cooking inside? Why should I do it instead of blanching and frying just once? The accepted answer to this question is that the fries should be cooked to begin with, which apparently is already the case with blanching. It seems to have something to do with starch molecules, but I'm interested in the details.


The double fry process consists of making a crispier potato chip. Tests have shown that less oil is also absorbed. So this is a general health benefit

The main purpose of blanching is for mass production to prevent potato chips from sticking together during packaging. It removes all surface thickness. Cold water rinsing is all that is needed for small scale production at home

Cooling and drying the chips between steps generally results in a better chip

The quality and suitability of the potatoes probably still has more to do with it than the cooking process

Interesting experiments at http://www.macheesmo.com/2010/02/the-great-baked-fry-experiment/

Heston Blumenthal completed a master class after looking for the perfect chip. It relates to the science of how starch is released when cooking, not blanching, and makes sense when it comes to drying the air to remove moisture. The first french fry seals the outside surface and is cooked hot so the potato roasts and seals absorb less fat. This is good for taste and health.

The second french fry colors and heats the french fries ready to eat.

Quotes him from a website that no longer exists:

These chips are one of my proudest legacies! You see them on menus across the country now, but the original recipe came from endless experimentation at home long before I even opened the Fat Duck. The first secret is to cook the fries until they almost fall apart as the cracks make them so crispy. The second secret is to let the french fries steam dry and then let them sit in the freezer for an hour to remove as much moisture as possible. The final secret is to cook the french fries in very hot oil for a crispy, glassy crust.

Recipe: Heston Blumenthal's triple cooked fries

Youtube Videos: How To Cook Perfect French Fries - In Search Of Perfection (BBS) And How To Cook Like Heston S01E06 Potato

I disagree with the assumption that blanching is supposed to prevent potatoes from sticking.

When blanching and frying the potatoes are first cooked at a lower temperature. This allows the first round to be cooked without the outer layers becoming crispy. The second "frying pan" is usually made of oil at a higher temperature, which makes the outside of the frying pan nice and crispy.

When using a french fry that is thicker than the "smallest" potatoes, the challenge is to cook the inside tenderly to a certain extent without overcooking the outside. If you cook it long enough for the heat to penetrate the center and the oil is at a temperature sufficient to crisp the outside, the outside will get darker, harder, thicker, and over-fried. If you turn the time or temperature down so that the outside is set correctly, you have undercooked insides or greasy and moist french fries.

I've done both and find that blanching (with a bit of baking soda in the water as suggested by Cook's Illustrated) gives me a nice fries.

The idea is to start the high temperature frying pan with an unscraped but partially cooked potato using either technique. Why fry twice instead of blanching and then frying? Probably just a matter of personal preference - maybe you don't get a "wet" roast that splatters when you put it back in the oil, maybe the first roast makes less of a starchy mess to handle ... I'm not sure. I guess, from practical "end product" considerations, there really isn't that much of a difference in how you cook the fries initially. In fact, if you google "double fry or blanch French fries," you'll see a lot of "double fry" articles that refer to the first step in frying as "blanching."

Back to the main topic of the question: if you are blanching, the one time roast is fine. There is no need to blanch and fry both.

If you cook it twice, the fries will absorb less fat.

The blanche process actually and most importantly results in a french fry that has a fluffy center and a crispy exterior. It's the superior method. Blanche, then fry. At one restaurant I've worked at, the best wedges I've ever had were bleached (in plenty of salt until almost completely cooked), chilled in the fridge, and then deep-fried (golden), which meant less cooking time on service needed in the fryer. French cuisine teaches Blanche to fry at a low temperature and flash fry again at a higher temperature for crispy skin. The french fries, however, result in a crispy exterior, but are not necessarily something that cannot be achieved by frying them once for a long period of time.

I boil them and fry them once over very high heat. That does the trick. I even tried double frying but didn't notice much of a difference.

I actually noticed that boiling it would roughen the surface and make it crispier. Spices added afterwards would also adhere better.

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