French fries are one of the most popular food items all year-round. It is every fast- food chain goer’s go to item every time.  For people who do not fancy fast food chains, they opt for frozen French fries readily available for purchase or simply, make their own French fries from scratch. But making French fries isn’t that simple. You gotta find a way to perfect it. And choosing which potatoes to use is already quite a challenge alone. Here’s a blog post about French fries and the Science behind.

A little history first

French fries or Belgian fries?

France has been credited to be the birthplace of pommes frites, French for fries. But the fries didn’t really originate from here, as most historians claim.

In the 17^th century, frying up fish for their meals was once a norm for the people of Belgium. But when the rivers became frozen in ice, they needed to find an alternative as it became difficult to fish. And they did by frying up long slices of potatoes, which they later called frieten.

But why French fries?

According to history, the Belgian army served and introduced deep-fried thin-sliced potatoes to American, British and Canadian soldiers during the First World War. Since the Belgian army’s official language was French and they spoke it, the word “French” became associated with fries since then.

What potatoes make good French fries?

Although potatoes can be processed into French fries, not all potatoes make good French fries. Processors and manufacturers set specific criteria to funnel which potatoes go for French fries making, and which do not. This is to ensure high out-turn, if possible.

Potatoes must be large enough and long-oblong for French fries making, long to long-oval for baking, round for canned new potatoes and round-oval for prepacking.

Dry matter should be high in potatoes

The moisture content is the amount of water found in potatoes while the dry matter is what remains if water is removed—this is where the feed nutrients are found. Stem tubers like potatoes are 80% water and 20% solids. This is the reason why they easily disintegrate when cooking. But dry matter content this high (although 20% to 25% is preferred) is good to achieve good fry color in fries.

Minimal after-cooking darkening (ACD)

Since a steadily growing industry, manufacturers and potato-processing entities have been looking for ways to prevent after-cooking darkening. This ACD happens when ferri-chlorogenic acid is oxidized in French fries.

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To fight ACD, potatoes can be soaked in cold water for about 3 to 4 hours— this also enhances the texture of fries when fried.

If one prefers blanching, adding sulfur enhances the process. After washing, additional blanching can be done by adding low concentration of glucose. This way, the level of reducing sugar is adjusted too, thus, resulting in a more stable color when fried.

Reducing sugars should be low

Reducing sugars, like the name suggests, are sugars that act as reducing agents (carbohydrates) that contain free aldehyde or ketone group. They are responsible for the color of food when cooked and must be defined to be within limits. The limits vary depending on how the potatoes are processed. In French fries making, these reducing sugars must be low (must not be higher than 0.5%).  Other processes require these reducing sugars at even lower amounts.

Other considerations

Through visual inspections, one can tell if potatoes are good to use at all. Infected potatoes usually have dry and sunken spots. If cut open, some potatoes may have very visible fungal growth.

How to make the perfect French fries

It’s kind of tricky to cook on first attempts if someone hasn’t cooked fries before. You want them to be golden and crispy.  Here are a few tips to achieving that.

The oil

There are many varieties of oil that people prefer. But a study showed that corn oil is what most fast food chains used to fry their fries. Corn oil is low in saturated and monounsaturated fats.

Regardless of what oil you prefer, you should have your oil pre-heated.

The main key to frying fries is temperature and time control. Cooking them at high temperature and short time may end in cooked exterior but uncooked interior. However, Cooking at low temperature may result in soggy fries.

Double frying

If you’ve never tried double frying your French fries before, you’ve been left behind. It’s time to upgrade your method.

See the sizzle that happens when you put your potatoes in the pan? You may think that it is the oil boiling—It’s actually water that is starting to evaporate, a hint that temperature isn’t yet high enough. But not all evaporates and expands, but gets trapped instead during the first fry. You can easily leave your potatoes longer in the oil, but they could be overcooked and you don’t like that.

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The trick here is by freezing to turn the water in the potatoes into ice crystals then fry it again.

It works every time because the moisture in the center of the potatoes goes to the exterior after they cool. Since the moisture is already on the outside, it’s now easier to eliminate during the final fry.

Not convinced? McDonald’s once revealed that they make their fries by blanching them in 170°F (76°C) water, frying then freezing before sending them to their branches, where they are fried again before being served to customers.

Anyway, after freezing, fry your fries at 375°F (190°C) for 4 to 5 minutes or until they’re golden in color. Another way to tell if the fries are done if they float in the oil for around half a minute.

Fast food chains and most restaurants just make their fries’ quality the same every time became they use commercial deep fryers. These deep fryers are equipped with thermostat to better observe temperature control.

Why do French fries get soggy and how to prevent it

Fries contain a lot of starches. These starches are hydrated during the cooking of fries. This hydration helps to obtain that brown and crispy appearance on the outside. And these starches are also the reason why you do not want them in fries. When the fries are starting to cool, the starches begin to discharge moisture and make the fries soggy.

If you buy fries from a fast food chain and intend not to eat it in the next 20 minutes, do not pack your fries in any way that will prevent moisture from escaping. If the moisture from your hot fries is trapped, it will just go back on your fries to make them soggy and taste bad, obviously.

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