The Food Lab: Better Home Cooking Through Science

(Nandana) #1

they can do it, then so can you.
Here’s what happens when you drop a piece of food into
a deep fryer:



  • Dehydration. Free water inside foods and in batters or
    breadings will evaporate at 212°F. As soon as your food
    hits the oil in a deep fryer, which for most recipes ranges
    from 300° to 400°F, moisture will rapidly convert into
    steam, releasing itself in a violent cascade of bubbles. This
    escape of moisture is what you see when you first lower
    food into a fryer. Within a few minutes (depending on the
    thickness of your food and temperature of your fryer),
    most of the free moisture in your food will have
    completely evaporated and the bubbling will slow down.
    After this, bound water from inside the food—that is,
    water that takes more energy to escape from its cellular
    prisons—will continue to be released in small streams of
    bubbles. Eventually, after all free and bound moisture has
    been expelled, you will no longer see bubbles coming
    from your food. At this stage, your potato chip is about as
    fried as it’s gonna get.

  • Expansion. This phenomenon occurs in foods that are
    coated in a batter or dredged in a mixture leavened with
    baking powder, whipped egg whites, or other ingredients
    that cause the formation of air bubbles. Hot air takes up
    more space than cold air, so the rapid change in
    temperature that occurs when you drop food into a fryer
    causes the air bubbles inside the batter around a piece of
    fried food to expand. In that way, it’s very similar to the
    way that a ball of dough will puff when put into a hot

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