Cooking
in oil (115)
El
aceite solo afecta la superficie
Deep frying, shallow frying, confit: in each of these
of techniques, the oil affects only the surface of the food. Below the surface,
heat is just heat; the food responds no differently than it would if it were
baked in air or boiled in water.
El aceite es un ingrediente
Whereas air and water are simply fluids that we cook
in, oil is much more: not only a cooking medium, but also an ingredient.
Jus like
baking, Only Faster (116)
Deep-frying works a lot like baking. In both
techniques, a convecting fluid transfers heat to food: the oil in a deep fryer
churns in response to differences in buoyancy between hot and cold layers, just
as the air in an oven does.
Wet bulb temperature
The temperature read by an ordenary (dry) thermometer, such as an oven thermometer o thermostat, is called dry bulb temperature. The temperature read by a thermometer that is wet (covered by a damp cloth, for example) is usually much cooler because of evaporation. This temperature is called the wet bulb temperature. Because food is wet, the real baking temperature in an oven is closer to this temperature.
Wet bulb temperature
The temperature read by an ordenary (dry) thermometer, such as an oven thermometer o thermostat, is called dry bulb temperature. The temperature read by a thermometer that is wet (covered by a damp cloth, for example) is usually much cooler because of evaporation. This temperature is called the wet bulb temperature. Because food is wet, the real baking temperature in an oven is closer to this temperature.
Wet bulb
temperature
Steam does emerge from the food less readily in oil
than it does in air. Oil puts a lid on evaporation: it contains the water vapor
coming from the food at least momentarily. The pockets of steam that envelop the
food raise the humidity and therefore the wet-bulb temperature, which remains
the effective cooking temperature as long as the surface of the food is wet.
Dry bulb
temperature
The temperature of the oil serves as the drybulb
temperature, like the temperature of the oven thermostat during baking.
(Although oil doesn't seem all that dry, the point is that oil doesn't have any
water in it.)
Wet bulb temperature vs. Dry bulb temperature
Wet bulb temperature vs. Dry bulb temperature
Mas juntas en la fritura
profunda que en el horno
The moisture-trapping ability of oil brings wet-bulb
and dry-bulb temperaturas closer together in deep-frying than they typically
are in baking.
Precalentar
Typical preheating temperatures, which range from
150-200 oc I 300-390 op, are lower than those used for high-temperature baking
because the oil will erupt into flames if it gets too near its smoke point
Tres etapas de la cocción (en el
horno y en la fritura profunda)
The duration of each stage is much shorter when frying
than when baking, however, so the process demands greater vigilance.
The
settling period (Periodo de asentamiento)
Once food enters the hot oil, things happen fast.
Swirling currents of oil heat the surface of the food to the wet-bulb
temperature in only a few seconds-a rushed version of the settling period that
occurs during baking (see photos on page 106). As long as bubbles are streaming
from the food, you can be sure that the surface is wet and thus no hotter than
boiling water. The cooking temperature at the food surface will remain a
constant 100 oc I 212 op as long as juices percolate from the moist interior to
the surface of the food at least as fast as water evaporates from the food
surface. The settling period may be over in an instant, or it may last a few
minutes. It will take longer for larger or thicker pieces of food, for food
coated in wet batter, and for foods in which the juices don't flow readily to
the surface.
During this phase of cooking, the jets of steam
bubbles stir and thus shrink the stagnant boundary layer that insulates the
food from the oil. The Jacuzzi-like action thus moves heat from the oil to the
food faster-often two or three times faster than occurs once the bubbles have
stopped emerging. But as with forced convection in an oven, faster heat
transfer during deep-frying simply accelerates drying.
The
constant-rate period (period de tasa constante)
Pay close attention when the streams of bubbles start
to slow: a mere trickle indicates that the surface is drying and that a crust
is forming. The food is nearly through the constant-rate period now and is
approaching the final stage of deepfrying, when it could easily burn. On
irregularly shaped food, some parts could burn even while other parts are still
bubbling.
Falling-rate period (Periodo de
tasa en caida)
At the end of deep-frying, during the falling rate
period, the temperature of the crust rises quickly, and the boiling zone moves
deeper into the food, just as they do in the final stage of baking. This is the
point at which the golden color and crispy or crunchy crust develop, the
raisons d' etre of deep-frying. This last stage also presents the principle
challenge of deep-frying, which is to cook the food to the center before the
crust burns. Although the same challenge must be faced during baking,
deep-frying is much less forgiving of imperfect timing because oil moves heat
much faster than air does.
Sized
Just Right (117)
Circulating hot oil transfers heat extremely rapidly,
so deep-frying is one of the fastest ways to cook the surface of food. Beneath
the surface, however, heat propagates in frying food in the same way it does in
any other cooking technique: slowly, through conduction. The mismatch between a
fast-cooking surface and a slow-cooking interior means that food needs to be
sized just right for deep-frying.
Si cortas la comida por la mitad
reducís el tiempo de cocción en 4
When in doubt, cut food into smaller pieces. Small
objects have a lower Biot number than large ones; they heat more evenly from
surface to center, and they also heat through faster. If you can cut the volume
of food in half, you will decrease the cooking time by as much as a factor of
four.
Bubble,
bubble, oil, and… steam (118)
Las
burbujas nos protejeran!
Probablemente oyeron que la comida cocinada en fritura
profunda se “sumerge en aceite”. Eso no es exactamente cierto. Si el aceite
esta en peak condition la comida no estará en contacto con el aceite mas que la
mitad del tiempo de cocción. El resto del tiempo el vapor de agua que sale de
la comida en forma de burbujas y empuja al aceite al costado.
Las burbujas de vapor previenen que la comida absorba
ningún aceite hasta que la fritura esta terminada. Solamente entonces la acción
capilar absorbe el aceite por las grietas seca y los poros del vegetal.
Después de la cocción la condensación crea un vacío
que empuja el aceite hacia adentro. La acción capilar entonces hace que el
aceite entre más profundamente.
Las columnas de vapor brotan de la superficie de los alimentos, interrumpiendo la capa circundante de aceite frío y permitiendo que el aceite caliente se precipite.
Las burbujas de vapor también empujan el aceite de la superficie de la comida, previniendo que el aceite entre en su interior.
Mientras la superficie esta húmeda: Hasta que la superficie se seca se mantiene dentro de la wet-bulb temperatura, que no puede superar la temperatura de hervor del agua.
Una vez que la superficie se seca se calienta rápidamente hacia la temperatura del aceite, y los almidones y azucares de la comida se caramelizan.
La temperatura de la superficie lentamente llega al interior de la comida más alla de la alta temperatura de la superficie.
In
Pursuit of the Golden crust (122)
1) One simple approach to avoid burning
is to turn down the temperature on your fryer.
2) A second strategy, which works well
for delicate foods that aren't too large, is to coat the food in a wet batter.
The coating fries into a superb crust even as it protects the food from
overcooking. In the oil, the water in the batter boils steadily, but a pocket
of cooler, humid air develops between the batter and the food . The food
essentially bakes in this cool zone of moist air rather than frying in the oil.
The thickness of the batter determines just how cool this blanket of air will
be. Thin, tempura-like batters have a slight cooling effect, whereas thick, wet
batters cool food substantially. Of course, batters have the added virtue of
producing the kinds of irresistible crusts that are a hallmark of great
deep-frying.
3) A third strategy that works well
with many kinds of food is multistep deep-frying-that is, cooking the food
before frying it.
The very best strategy for deep-frying tender or delicate foods,
however, is to precook the food sous vide.
Oil Changes (123)
El aceite como ingrediente
Las edades del aceite
Escoba nueva no barre bien
Straight from the can
or bottle, most frying oil is practically odorless and tasteless because the
chemical reactions that produce flavorful compounds haven't been completed yet.
Food cooked in fresh oil also browns less quickly and evenly.
In fact,
food frying in fresh oil spends as little as one-tenth of the cooking time in
contact with the hot oil. Little wonder that it takes longer to cook. The
meager browning you see when frying with fresh oil is a dead giveaway that
caramelization and Maillard reactions haven't occurred, so the food is bound to
lack flavor, too.
Un aceite maduro
After
repeated use, frying oil goes through another set of chemical reactions, called
hydrolysis, that split and rearrange some of the fat molecules. Among the new
reaction products are surfactants-also known as emulsifiers-that allow oil and
water to mix.
Food cooked
in oil that's been "broken in" this way will spend upwards of half of
the total frying time in contact with the oil. With heat being delivered more
rapidly, the food cooks faster to higher temperatures, an even golden-brown
color, and a more robust flavor.
Viejo y rancio
Unfortunately,
oil cannot be kept in its peak condition forever. The reactions that improve it
ultimately ruin it
The secret Life of Frying Oil (124)
So change
your frying oil regularly, and, if you're using a pot of oil or a
noncirculating heating bath for deep-frying, strain the oil often to remove
food particles.
Taming Grease (125)
¿Por que sos tan grasa?
If bubbling
steam prevents oil from infusing into deep-frying food while it's cooking, how
is it that poorly fried food is so often greasy? The answer lies in what
happens to the food after the fry cook removes it from the oil and it begins to
cool.
Those same
volcano-like fissures and holes in the food through which steam escaped now
become caves of condensation (see diagram below). As vapor condenses back to
water in the crust, it creates a slight vacuum that sucks in oil from the
surface. Capillary action then does most of the work of making food greasy by
piping the oil deep into the dried crust.
Papel de cocina
Simply
blotting deep-fried food as soon as it emerges from the fryer will make it a
lot less greasy.
1)
Volcanes de vapor se forman cuando el aceite
hierve el agua que esta en la comida, que migra a la superficie desde el
interior.
2)
El vapor sale a la superficie por poros y
fisuras impide que el aceite entre en la comida durante la cocción.
3)
Después de la cocción la condensación crea vacio
que empuja el aceite hacia adentro, la acción capilar luego hace que el aceite
penetre aun mas.
Controlar la cantidad
de aceite (127)
1) La edad del aceite. One is the age of the oil; older frying oil becomes more viscous, so it
clings more stubbornly to the food than fresher oil does.
2) La temperature del aciete. Oil thickens as the temperature drops, so less of it will drain from
the surface if you cook at lower temperatures. Exacerbating that effect, lower
frying temperatures also tend to produce a thick, leathery crust that absorbs
more oil after cooking.
Cooking French fries in oil just 10 ·c I 18 •p below the recommended
temperature of 180- 185 •c I 355-365 •p can increase the oil absorption by 40%.
To minimize grease and get a thin, delicate crust, it's always best to deep-fry
at the highest temperature practical-but not so high that your crust burns or
scorches.
3) El tamaño de la comida. A third variable is the thickness of
the food. Thin foods have proportionally more crust than interior volume, and
the crust is where oil is absorbed. So it stands to reason that, weight for
weight, potato chips can absorb two to three times more oil than the same
amount of French fries, simply because the chips are all crust.
Volumen 5
Fish and Chips (143)
Halibut cheed gel base
Hacen un gel con caldo, Low acyl gellan, sodium citrate, high acyl gellan. Hidratan los hidrocolicos y lo mantienen a 65 grados. Pasan el pescado tres veces por el gel y luego lo enfrian durante una hora.
Siphoned Tempura Batter
Tempura en sifon con: Harina, harina de arroz, polvo de horneas, vodka, agua, jarabe de malta. Trisol.
Trisol can be replaced by other modified starches, such as Batterbind S from National Starch or simply a commodity starch such as rice flour or tapioca
Temperatura del aceite 190
