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

Question

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.

Answer

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

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Should french fries be fried two times?

Question

Most professional cookbooks tell me to fry french fries two times. First at a lower temperature of about 150-170°C and then at a higher temperature about 180-190°C.

Reference: http://en.wikibooks.org/wiki/Cookbook:French_Fries#Variations

Related: What varieties of potato would be good for chips / french fries?

What are the advantages of frying the potatoes two times?

Answer

The lower (first) temperature actually cooks the potato so that it is tender, the hotter temperature (second) is what gives the crispy golden coating.

If you just did the lower temperature, your fries might be too soft. If you just did the hotter temperature they would be too too tough.

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How much of the oil will stay in french fries?

Question

Is there a fixed percentage of how much of the oil used to frying french fries will stay in the served french fries?

I guess that it depends on things like dimension of the french fries, frying temperature, oil type.

Answer

There's too many factors to have a set percentage of oil that will stay, but lets cover a few common things that determine the oil in your final product.

Heat of the oil:

• Your oil needs to be plenty hot enough to actually fry in. For fries, you'll typically want to shoot for between 350-375 F. If you don't have a thermometer, then get one! If you really don't want to get one, a white bread cube will fry brown in about 60 seconds at the right temp - but a thermometer is best. If the oil isn't hot enough to fry in, it will start to absorb the oil. So before you ever fry anything, get that oil up to temp (and make sure its that way between batches!).

Coating of the fry (or other fried food):

• A batter coating is just going to hold more oil than a plain french fry. If you're trying to be health conscious about french fries (but then again, why are you eating french fries!?!), avoid batter coating them and go with a 'plain' fry.

Post frying treatment:

• Shake, shake, shake! Give the basket a good vigorous shake. Don't have a basket? Use a strainer or at least a cooling rack with a mesh-type grate. You're trying to physically shake as much oil off the fry as you can. Additionally, I like to lay them on paper towels and then fold the paper towels on top. See all that oil? Simple math, if its on the paper towel, its not in the fry anymore.

Crowding the pan:

• If you crowd the pan you fry in, you'll lower the temperature of the oil and give the oil not enough circulation. This means longer to fry and more time not at the right temperature. This means more oil in the final product. Its better to do some smaller batches than to try to cram it all in one batch.

The right oil:

• The main thing here is that you need an oil that can fry hot enough without smoking. This goes back to the right temperature. (In case it hadn't sunk in yet, temperature is important!) If you can't get it hot enough, then you're going to absorb a lot of oil. Olive oil is a bad choice. I usually use peanut or canola oil.

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Why do i have to fry french fries two times?

Question

Most professional cookbooks tell me to fry french fries two times. First at a lower temperature of about 150-170°C. Then at a higher temperature about 180-190°C.

Reference: http://en.wikibooks.org/wiki/Cookbook:French_Fries#Variations

Related: What varieties of potato would be good for chips / french fries?

What are the advantages of frying the potatoes two times?

Answer

The lower (first) temperature actually cooks the potato so that it is tender, the hotter temperature (second) is what gives the crispy golden coating.

If you just did the lower temperature, your fries might be too soft. If you just did the hotter temperature they would be too too tough.

Check more discussion of this question.

Tricks to preserve chips (french fries)?

Question

Since I can remember I've always been crazy about chips (french fries for the Americans). As a result I always make too much when I make them for me. The problem I have and have always had is that they never seem to keep very well. The minute they cool off they become floury and stale. I find that this even happens with oven chips.

When I was a kid my mother used to reheat chips for me in the morning, melting some butter over it, which help rehydrate them somewhat and give them a bit of flavour, but this never really worked all too well.

What I'd like to know is if any of you know of some tricks to help preserve the chips? And also for interest's sake why this happens? This never seems to happen with baked potato or mash. They do lose some of their flavour sometimes, but not in the same way chips do.

Answer

Here is an excellent recipe by the guys over at Cooking Issues (and also a follow up report) with almost everything you'd ever want to know about chips. That first recipe is supposedly good even after they've cooled off:

Our standard fries are good even when cold.

Another option is to cook a lot of chips but stop after their first frying and freeze them; when you want to eat them, simply put the frozen chips into the fryer for the second frying. This also has added benefits:

Freezing acts like partial dehydration. When the frozen fries are finished, they liberate water freely, leading to rapid dehydration and good crust formation with a porous interior. Pre-frozen fries are crunchier than fresh and stay crisper longer after they are fried, but they tend toward hollow fry.

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