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I love good fries fries. I've made them with some success at home using the Steak Frites 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 did not involve blanching, and I've been convinced through research that blanching them can be helpful.

In another recipe I've found for twice-cooked fries, they are merely blanched and then fried. Is this technique going to produce good fries?

According to Serious Eats fries from McDonald's are both blanched and fried at a lower temperature, frozen, and then finally fried before being served to you.

The French Culinary Institute has a technique that pre-blanches, blanches, freezes, and then twice fries - talk about work!

From what I've read pectin is released during the blanching at certain temperatures. Also the blanching removes some external starches, which I assume rinsing and soaking may accomplish. Plus if you blanch in salted water you pre-salt the fries.

My question is, what does that initial lower temperature fry do? Cook the inside? Why should I do it instead of just blanching and frying once? The accepted answer to this question says the initial fry is to cook the fries, which it seems blanching already does. It seems to have something to do with starch molecules, but I'm interested in the details.

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I don't know the science behind it but I sure taste the difference – Davy8 Jan 8 '12 at 0:22
up vote 3 down vote accepted

The double fry process is to make a crisper potato chip. Tests have indicated that less oil is absorbed too, so this is a general health benefit

The blanch process is mainly for mass production reasons to stop potato chips from sticking together when packed. It removes all surface starch. Cold water rinsing is all that is needed for home, small scale production

Cooling and drying the chips between steps generally makes for a better chip

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

Blanched chips drying

Interesting experiments at

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I'm aware of the different uses of chips, crisps, and fries in the various English dialects, but even so I'm not sure you're talking about American French fries/Commonwealth chips here... If so, it'd probably be best to use the same dialect as the question (so stick with French fry) – derobert Jan 9 '12 at 14:49
Hmmm. Fair enough. Though French fries mean different thing in different parts of the world too. We just call them "chips". My thinking was; Potato = Potato and chip is a common word for a common process for lots of thing, not just potatoes, and this does not just apply to straight cut either, so somewhat more self explanatory. Photos do a lot of talking :-) – TFD Jan 13 '12 at 6:47
Here in NZ when we chip Kumera (sweet potato), we tend to make rough disc shapes as they more often grow as long narrow tubers, more than fat potato size tubers – TFD Jan 13 '12 at 6:50

OK Heston Blumenthal did a master class following his research into the perfect chip,he refers to the science of how starch is released in boiling rather than blanching and makes good sense in reasoning for air drying to remove moisture. The first fry seals the outer surface and is done hot so the potato sears and seals reducing fat up take, this is good for taste crunch and health.

The second fry colours and heats the fries ready to eat. I have done this and it works

this link is the text version of Hestons method Heston: "These chips are one of my proudest legacies! You see them on menus up and down the country now but the original recipe came out of endless experimenting at home long before I even opened the Fat Duck. The first secret is cooking the chips until they are almost falling apart as the cracks are what makes them so crispy. The second secret is allowing the chips to steam dry then sit in the freezer for an hour to get rid of as much moisture as possible. The final secret is to cook the chips in very hot oil for a crispy, glass-like crust."

this link is to the tv program showing him demonstrating and naratting the process and reasons you have to register but it is free.

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When you cook it twice, the fries will absorbe fat less the second time.

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An idea if this is true beyond doubt and more importantly, why? – Marc Luxen Jan 15 at 10:15

Yes, I am digging deep into this as well. I experimented with blanching in salt vinagre water (serious eats advice), and single fry or double fry. I do not see much difference, really. But I am also interested WHY and WHAT happens during the first fry. I think the problem is that you want to strengthen the pectin on the outside, and destroy it inside for a fluffy inside. A short soak in vinagre, followed by a boil in acid/salt water should do that trick..did anyone try that? Point here is, that the first fry seems unnecessary once you blanch, the outside is already sealed by the fortified pectin in the walls. I dont see how a first fry would actually would help, because you do not brown at all...and you dont have to pre cook, because you have done that already. So I am curious to know: does anyone know what happens, or is suppose to happen during that first fry? Chemically?

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