The Food Lab: Better Home Cooking Through Science

Q: So why do we bother searing at all?
It’s simple: flavor. The high heat of searing triggers the
cascade of chemical reactions known as the Maillard
reaction. I’ve referred to this elsewhere, but here’s a quick
recap.
Named after Louis-Camille Maillard, the scientist who
discovered it, the Maillard reaction is the complex series of
chemical reactions that causes foods to brown. It’s often
confused with caramelization (“That steak has a beautifully
caramelized crust!”), but in fact the two reactions are
distinct. Caramelization occurs when sugars are heated,
while the Maillard reaction occurs when sugars and proteins
are heated. The places you’re most likely to see it are when
searing or roasting meat (meat contains natural sugars),
when baking bread or making a piece of toast (flour
contains carbohydrates built with sugars and proteins), or
when roasting coffee beans.
Although Maillard reactions can occur at relatively low
temperatures, they are glacially slow until your food reaches
around 350°F. That’s why boiled foods, which have an
upper limit of 212°F (determined by the boiling point of
water), will never brown. With high-temperature searing,
frying, or roasting, however, browning is abundant. First a
carbohydrate reacts with an amino acid (the building blocks
of protein), which then continues to react, forming literally
hundreds of by-products that will in turn react with each
other to form still more by-products. To this day, the exact
set of reactions that occurs when Maillard browning takes
place has not been fully mapped out or understood. What
we do understand is this: it’s darn delicious. Not only does it