To
Sauté or Not to Sauté? That is the Question
By FBWorld Team
Ask
The Food Lab: Do I Need To Sauté Vegetables
When Starting a Stew?
QUESTION:
Do I Need To Sauté Vegetables When Starting a Stew?
Is it necessary to sauté aromatics in a dish like
a soup or stew that will cook for a long time? Many of
my soups, stews, and curries have a base of mirepoix,
or onions, and maybe garlic and ginger. I'm wondering
in a dish that cooks for 1 hour or more is it necessary
to start with the sauté? Does the sauté
process add something to the flavor or texture that simmering
in liquid wouldn't, or perhaps would I find that the onion
would take a very long time to cook while simmering in
a soup?
ANSWER:
Whether it's the classic French mirepoix of onions, celery,
and carrots cooked in butter, the New Orleans holy trinity
of onions, celery, and bell peppers sweated in oil, or
perhaps just some leeks and garlic cooked down in olive
oil, most stews and soups start the same way: sautéeing
veggies.
If
long-stewing is going to soften up your vegetables anyway,
why bother softening them in fat to begin with? It's a
good question, and one that you can quickly get a practical
answer to just by trying it out:
Make
a batch of an easy chili recipe, like this 30-Minute
Chipotle Chicken Chili, but rather than cooking
it all in one pot, divide the ingredients in half. Into
one pot, dump all of the ingredients, turn on the heat,
and let it go. In the second, follow the instructions
as written by sweating out the onions in the oil first,
followed by adding some of the other aromatics (the garlic
and spices), and finally adding the liquid, beans, and
meat.
Now
taste the two side-by-side. What do you taste? Here's
a hint for those of you who didn't actually follow the
instructions in the previous paragraph: The chili in which
the onions were sautéed will have a mellower, more
balanced aroma and a slightly sweeter flavor. It'll taste
smoother, more integrated, married better. The one in
which the ingredients were simply dumped in will taste
off, with a stronger sulfurous aroma and a strange raw
pungency. Why the difference?
It has to do with the way aromatic compounds combine with
each other in the pot.
See,
vegetables contain many different aromatic molecules trapped
inside their cells. But the aromas you get from raw vegetables
are quite different from those you get from cooked vegetables.
In fact, the aromas you get from whole vegetables is even
different from those that you get from vegetables that
have been finely chopped, grated, or have otherwise had
their cells ruptured. This is all due to reactions that
take place between chemical precursors inside the vegetables
cells.
When
those cells are ruptured, these precursors come into contact
with each other and recombine into new compounds. Heat
and time can increase the rate of these reactions, and
indeed cause brand new ones to occur.
[Photographs: J. Kenji Lopez-Alt]
The
most famous example of these are in onions. When you first
cut open an onion, it has barely any aroma at all. It's
only after a few chemicals inside its cells (called lachrymators,
from the Latin root for "cry") are combined
that its familiar sulfurous, pungent aroma begins to form.
Let a cut onion sit in a sealed container over night,
and that smell will become quite powerful indeed. Subsequently
heating these compounds will cause them to continue to
convert to different, less pungent ones, and eventually
an onion will soften into a mellow sweetness.
So
why does it happen when you cook in oil but not when you
simmer them in water? There are two major factors at play:
heat and concentration.
Onions
and other vegetables cooked in a large pot of water are
limited to a maximum temperature of 212°F. This is
too low for some of these specific reactions to take place
(most famously the Maillard browning reactions). In a
pot with oil, on the other hand, you have the ability
to heat your vegetables to a higher temperature.
Secondly,
concentration plays a large role. When you've got vegetables
in a pot with a small amount of oil, the chemicals they
are releasing are in an extremely confined area. Some
of them may jump right off into the atmosphere to escape
(that's why sautéeing onions smell so good!), while
others will react with each other due to their close proximity
and intense jostling. Throw the same amount of vegetables
into a large pot of water, and you've diluted those reactants
to the point where they are far less likely to bump into
each other-and that's assuming that they even reach a
high enough temperature to react in the first place.
Moral
of the story: There's no shortcut to good flavor,
unfortunately. While certain vegetables can work just
fine added directly to simmering soups and stews (say,
carrots and celery), other vegetables (onions, garlic,
and the like) will almost always need at least a brief
sweat in a fat-based liquid before adding the remaining
ingredients.
EDIT:
This is not to say that with certain recipes that call
for raw vegetables to be used that you should sauté
them first. Some times that more sulfurous but fresher
flavor is what you're going for. Chicken soup or a plain
chicken stock, for example. The point is, if a recipe
calls for sautéeing, you can't skip the step and
hope to end up with the same results!
Got
a question for The Food Lab?
Email your questions to AskTheFoodLab@seriouseats.com,
and please include your Serious
Eats user name in your email. All questions
will be read, though unfortunately not all can be answered.
For the record, dry spices behave in much the same way
and should be toasted in fat or in a dry skillet in order
to fully develop their flavors.
About
the author: J.
Kenji Lopez-Alt is the Chief Creative Officer
of Serious Eats where he likes to explore the science
of home cooking in his weekly column The
Food Lab. You can follow him at @thefoodlab
on Twitter, or at The
Food Lab on Facebook.
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