Wok Skills 101: How to Deep Fry at Home
Note: It's Wok Week! Each day this week, J.Kenji Lopez-Alt will pick a different basic cooking technique the wok excels at, along with a couple simple recipes to highlight them. We'll cover steaming, frying, stir-frying, smoking, braising. Today, it's time for: frying. —The Mgmt.
Shrimp Tempura with Creamy Spicy Yuzu Sauce
I'd be willing to wager that anyone who complains how difficult and messy it is to deep-fry at home has never tried deep-frying in a wok. Why don't people fry at home? The most common answers are: it's messy, it's expensive ("What do I do with all the leftover oil?"), and it's unhealthy.
Well a wok can certainly help solve your first two problems. You're on your own for the third. Frying adds fat to your food, period. Try eating a few fewer french fries or only half of a spring roll if you don't want the extra calories. Alternatively, get a dog and spend all day running after him to make sure he's not peeing on doing something else he's not supposed to. That's how I get my exercise these days.
The flared sides of a wok offer several advantages over a straight-sided saucepot or Dutch oven:
- There is less mess. If you've ever tried deep-frying in a Dutch oven, you know that your range gets splattered with little droplets of oil splashing out from the sizzling food inside the pot. A wok, on the other hand, flares out a good three inches or so on either side from where the edge of the oil is, catching those drips and keeping your counter neat and clean.
- It's easier to maneuver. To get the crispest food possible, it's important to keep it moving (more on that below). Many times, you'll also need to flip foods while frying. The flared shape of a wok makes it easy to reach in with a spider or chopsticks, and gives you plenty of room to work in.
- There is less chance of a boil-over. Having a pot of hot oil boil over on you is amongst the worst kitchen disasters. It ranks up there with old hand-in-the-blender and Sabrina. It happens when you add too much moist or cold food to a too-full pot of oil. The food rapidly releases bubbles of water vapor, those bubbles pile up on top of each other, and over the edge they go. Since a wok widens out at the top, there is much more volume for those bubbles to expand to, their surface area increases, weakening their structure, and they pop before they get a chance to go up and order.
- It's easier to keep the oil clean, making it more economical. The corners of a Dutch oven can harbor burnt bread crumbs, little bits of french fry, and other hard-to-reach baddies. In a wok, there's no place to hide. Food particles left in hot oil are the main reason why it breaks down and becomes unusable. Oil that's carefully cleaned should last for at least a dozen frying sessions, if not more.
No matter what cooking vessel you choose to fry in, here are ten tips to ensure that your frying will be successful:
1. Use a Thermometer
There is no other way to ensure that your oil is at the right temperature. Depending on what you're cooking, you'll need to use different oil temperatures. For example, french fries fried at 300°F will never crisp up, whereas chicken fried at 425°F will burn on the exterior before it's fully cooked through. A thermometer is the only way to guarantee that you're cooking things right.
For the record: Many people claim that foods fried at a temperature that is too low will absorb more fat than food fried at a higher temperature. This is an easily unproven (but far-reaching) kitchen myth made up to make people feel better about eating delicious fried food. Don't believe it. Foods fried at a higher temperature absorb more fat. On the other hand, they also gets crisper, and stay crisper longer. That's why you want to fry at a high temperature.
2. Don't Fear the Fat!
A hot wok of oil is nothing to be trifled with, but just like pit bulls, they can sense fear. Timid novice fryers often decide to keep their hands a safe distance from the oil by dropping food into it from a height. The food ends up splashing hot oil out of the wok, and onto their skin and clothes, making them even more scared to do it the next time.
The goal when adding food to a fryer should be to minimize splashing. You do this by bringing your hand (or tongs, if you're using them) as close to the surface of the oil as possible before dropping in the food. For small pieces of food that are a couple inches or less, this means getting your fingers to about an inch of height.
For larger pieces—a whole fish filet, say—it means dipping it in and gently lowering it into the food until only the last inch sticks out of the surface of the oil before dropping it. This method of lowering foods in individually will also keep battered items from sticking together in a large mass.
3. Avoid Crowds
Adding too much food to the hot oil in a single go will cause the oil temperature to drop rapidly, reducing the effectiveness of your fry. Your food won't crisp properly, and batter-coated foods may lose some of their coat. A good rule of thumb is to never add more than a half pound of refrigerator-temperature food per quart of hot oil. So if you want to cook that 1-pound batch of fries, you've gotta use a full gallon of oil, or go in batches (I suggest batches). Of course, frozen foods should be fried in even smaller batches.
4. Dry = Good
Aside from causing proteins to set (just like any heated cooking process), deep-frying is essentially a process of dehydration. The hot oil causes water to rapidly transform to steam, which escapes and allows a crust to form. So it stands to reason that the drier your food is to begin with, the more effectively it'll fry. Surface moisture can also cause undue bubbling and more rapid break-down of your oil. For best results, all solid foods to be fried should first be patted dry, make sure that excess batter is allowed to drip off of battered foods before adding it to the oil.
5. Keep it Clean
The more oil gets used, the less effective its frying ability. The main factors that affect oil breakdown are small particles of food and moisture. To extend the life of your fry oil, you should constantly keep it clean. Whenever I fry, I keep a skimmer nearby to fish out any breadcrumbs, bits of tempura batter, or other food particles between (or even during!) batches. To remove debris, I start by swirling the oil in a clockwise direction with the skimmer. I then flip the skimmer around and give it a pas in the counter-clockwise direction. The flow of the oil should force the majority of food particles into its mesh. Deposit the debris in a metal bowl kept handy (do NOT throw hot oil into a garbage can with a plastic liner!), and repeat until the oil is clean.
6. Move it Around
Ever notice how when you're in a cool swimming pool if you stand still, you'll feel a little warmer until someone swims by and creates a current around you that cools you down again? Well the opposite thing happens with cold food in hot oil. If you allow them to sit still, a pocket of cooler oil will develop around pieces of food, reducing the effectiveness of the fry.
By constantly agitating the food and moving it around, you're continuously exposing it to fresh, hot oil. Your food will fry more evenly, and come out crisper than the simpler dunk-and-sit method. A metal skimmer, a cheap Chinese spider, or a pair of long chopsticks are the best tool for this job,
7. Choose Your Oil Wisely
The best oils for deep-frying are relatively cheap, flavorless oils with high smoke points. Flavorful oils like sesame oil or extra-virgin oilve oil contain compounds that cause them to smoke far below the effective frying temperature for most foods. Your best bets are plain-tasting vegetables oils like peanut, canola, or sunflower. Highly saturated oils will produce crisper crusts in foods, but can end up tasting greasy or even waxy if you allow them to cool too much before eating. They are also arguably more unhealthy for you. Because they are highly saturated, clean animal fats like lard or duck fat also make excellent frying oils, though their expense can be prohibitive.
Other oils have their adherents, but peanut is my personal medium of choice. Chichi prefers lard.
8. Drain Quickly, and Use Paper!
The majority of oil is absorbed into fried foods within the first few seconds out of the fryer as its internal temperature drops and oil rushes in to take up the space formerly occupied by water vapor.
While it may seem logical to drain fried foods on a metal rack, it's actually far more effective to drain on a paper towel-lined plate or bowl. On a rack, very little oil actually drips out of the food—the oil's surface tension keeps it in place. A paper towel, on the other hand, wicks oil away through capillary action, effectively drawing more fat out of the goods, helping it stay crisp longer. In fact, in a side by side test that I did, I found that the paper towels drew out nearly four times as much oil from the food as a simple rest on the rack.
To get the least greasy food possible, drop your food directly from the fryer into a paper-towel lined bowl and toss it to absorb oil from all sides.
By the way, for this reason, you should avoid using those metal rest-in-the-wok draining racks.
9. Season Immediately
I had an old chef who was fond of saying "I don't care if you've just fried dog sh*t. If it comes out of the fryer, you season it the second it does!" And he's right. Salt sticks and dissolves more rapidly to hot surfaces, so the sooner you season your food when it comes out of the wok, the better it'll taste down the line.
10. Reuse Your Oil
If you follow all of these tips, you should be able to reuse your oil for many many frying sessions before it starts breaking down on you. To save your oil, let it cool in the wok, then pour it out into a large liquid measuring cup. From there, pour it right back into its original bottles (or an empty soda bottle) through a funnel. Seal the cap, and store it in the fridge until the next time you need it.
If it starts getting very dark or produces foamy bubbles on its surface when you start heating it, it's probably past its prime and should be disposed of.
Got all that? Great—here's a recipe as a reward!
This crispy, spicy shrimp is a recipe from Boston chef Ken Oringer. I used to make them when I was cooking at Uni, his modern sashimi bar. They're a riff on Nobu's Rock Shrimp Tempura in Creamy Spicy Sauce that replaces his chili-garlic sauce with Korean gochujang (fermented glutinous rice and chili paste). The spicy mayonnaise is totally addictive and worth the cost of admission alone.
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About the author: After graduating from MIT, J. Kenji Lopez-Alt spent many years as a chef, recipe developer, writer, and editor in Boston. He now lives in New York with his wife. Got a suggestion for an upcoming topic? Email Kenji here, and he'll do his best to answer your queries in a future post. Become a fan of The Food Lab on Facebook for play-by-plays on future kitchen tests and recipe experiments