Freír las patatas en aceite frío para lograr un exterior crujiente
Las patatas fritas en aceite frío quedan más crujientes por fuera y esponjosas por dentro, porque se cocinan de forma uniforme y lenta.
Just as you start boiling potatoes with cold water, it's best to start frying them with cold oil. Root vegetables, like potatoes, contain a lot of starch. When you put them in boiling water, this starch forms a gelatinous layer that softens, detaches from the potato, and leaves the inside uncooked.
With cold oil, all the potatoes start at the same temperature and heat evenly and slowly, which better preserves their natural moisture. In contrast, in hot oil they lose moisture quickly and absorb more oil. With the gradual change in temperature, they don't become as saturated, and when they brown, they are crispy on the outside and fluffy on the inside.
This method also saves time and effort, and avoids the burns that usually result from throwing cold potatoes into boiling oil.
For this to work, it's important to use the right variety. Russet potatoes have low moisture content and high starch, which helps achieve a soft interior, and Yukon Gold potatoes also work. Although it's tempting, don't stir the potatoes in the oil: they start cooking before it even boils and break down easily. Let them rest, keep an eye on them, and remove them when they're golden brown.
The technique works with vegetable, canola, or beef oils, and allows for adding flavor. A few cloves of garlic in the cold oil release their sweetness as they cook, without burning.
