4 kitchen tips from a 'mad scientist'

J. Kenji Lopez-Alt comes from a family of scientists. His grandfather was an organic chemist, his father was a microbiologist, and even though he grew up to be a chef, Lopez-Alt first graduated from MIT.

He's taken all that chemistry and science into the kitchen with him. He considers himself "part mad scientist, part cook."

His new book, "Food Lab," cracks the secrets of home cooking with research and science behind every recommendation. He cooked hundreds of pounds of steak before perfecting his carne asada recipe, and he meticulously weighed mushrooms to see how much moisture they absorbed. He can tell you how to cook eggs down to the second, and what balance of acid and oil make the ideal vinaigrette.

Lopez-Alt joined food writer Dara Moskowitz Grumdahl to talk about his techniques and his new cookbook.

4 kitchen tips from the mastermind behind "Food Lab"

1) Don't just scoop your flour — weigh it

Ask ten people to measure out a cup of flour and you'll likely get ten different amounts, Lopez-Alt says. Some people pack the flour tight, some don't. Some cram 6 oz. into a cup measure, some fit only 4.

That 50% difference can completely change a recipe. That's why it's better to weigh the flour, Lopez-Alt says, and get a more precise measurement.

2) Use a cooler to cook your steak

Using a cooler to cook something might sound crazy, but coolers can be just as good at keeping things hot as they are at keeping things cold, Lopez-Alt says.

To cook the perfect steak, Lopez-Alt recommends turning a beer cooler into your own sous-vide machine. (A sous-vide machine is a gourmet tool that keeps water at a precise temperature to cook food sealed in vacuum bags.)

You'll need a solid cooler with a tight-fitting lid that can hold at least 2.5 gallons of water. Season your steak, seal it in a zipper-lock freezer bag with as little air as possible and fill the cooler with water ranging from approximately 133 to 143 degrees, depending on how well-done you like your steak.

Precise timing and seasoning instructions, depending on your cut, are available in the "Food Lab" book.

3) Go ahead, wash your mushroom

There's a popular kitchen myth that washing mushrooms means they'll end up holding all that water.

Not so much, says Lopez-Alt. He tested his mushroom-washing theory and found that, at most, washed mushrooms took 15 to 30 seconds longer to cook. Drying them off before cooking is key, but giving them a thorough wash won't hurt your recipe.

4) Don't turn your sausages into the Incredible Hulk

Throwing your sausages on the highest heat possible is not the way to go. When you do that, "what happens next is sort of like what happens to the Incredible Hulk, but instead of the Hulk growing faster than his clothes, imagine his clothes shrinking in proportion to his body."

The sausage will burst and most of the flavor will be lost on the flames.

Lopez-Alt recommends the simmer-then-fry technique, or cooking sausages on indirect heat with some direct heat at the end to give it a grilled look.

Get cookin'

"The Food Lab" proves that science is delicious. Try two of Lopez-Alt's recipes from his new cook book.

Lemon Ricotta Pancakes

These are special-occasion pancakes. Serve them for brunch, at your own risk — you will secure yourself the top seed as host for every brunch in the future.

Makes 12 pancakes, serving 3 to 4

• 1/2 cup buttermilk
• 1 cup fresh Ricotta, drained for 30 minutes
• 2 tablespoons unsalted butter, melted and slightly cooled
• 2 large eggs
• 1/2 teaspoon vanilla extract
• 1 cup basic dry pancake mix
• 2 teaspoons grated lemon zest (from 1 lemon)
• Vegetable oil for cooking
• Maple syrup

1. Whisk together the buttermilk, ricotta, melted butter, eggs, and vanilla extract in a medium bowl. Add the pancake mix and lemon zest and whisk until no dry flour remains (the mixture should remain lumpy — be careful not to overmix).

2. Heat ½ teaspoon oil in a 12-inch heavy-bottomed nonstick skillet over medium-high heat (or use an electric griddle) until it shimmers. Reduce the heat to medium and wipe out the skillet with a paper towel. Use a 1/4-cup dry measure to scoop 4 pancakes into the pan and cook on the first side until bubbles start to appear on top and the bottoms are golden brown, 2 to 3 minutes. Flip the pancakes and cook until the second side is golden brown, about 2 minutes longer. Serve the pancakes immediately, or keep warm on a wire rack set on a baking sheet in a warm oven while you cook the remaining batches. Serve with maple syrup.

Extra-Sweet Roasted Sweet Potatoes

Serves 6 to 8

• 5 pounds sweet potatoes, peeled and cut into 1/2-inch disks or 1-inch chunks
• 1/4 cup olive oil
• Kosher salt and freshly ground black pepper

1. Bring 3 quarts of water to a boil in a large pot over high heat. Remove from the heat and add 4 cups of room-temperature (70°F) water, then immediately add the potatoes and cover the pot. Place in a warm spot and let stand for at least 1 hour, and up to 3 hours.

2. When ready to roast the potatoes, adjust the oven racks to the upper- and lower-middle positions and preheat the oven to 400°F. Drain the sweet potatoes and transfer to a large bowl. Toss with the olive oil and season to taste with salt and pepper.

3. Spread the sweet potatoes on two rimmed baking sheets and roast until the bottoms are browned, about 30 minutes. Carefully flip the potatoes with a thin offset spatula and roast until the second side is browned and potatoes are tender, about 20 minutes longer. Serve immediately.

Photography and recipes from "The Food Lab: Better Home Cooking Through Science" by J. Kenji Lopez-Alt. Copyright © 2015 by J. Kenji Lopez-Alt. With permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.