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12 of your biggest cooking questions answered with science

Wait, you *don't* put vodka in your pie crust?

LYDIA RAMSEY, BUSINESS INSIDER
23 MAY 2016
 

If you're like me, there are some parts of cooking that are completely baffling. I'm not just talking about figuring out the recipe. Sometimes I also just wonder what sort of chemical reactions are going on that makes the food taste so good and turn out the right - or wrong - way.

Without further ado, here are the scientific answers to some of your biggest quandaries in the kitchen.

 

How much water do I need to cook my rice?

Here's a general rule: For every cup of rice you cook, you'll need two cups of water.

However, Dan Souza, the executive editor of Cook's Science at America's Test Kitchen and one of the authors of The Science of Good Cooking, told Business Insider that this isn't always true. There are a number of other factors that influence how much water you're going to need, including what size the pot is and how much evaporates.

"If you have a ratio of 1:2 and you double that to 2:4, you're saying you're going to get double evaporating because you doubled it, and that's not true," he said.

So keep this in mind the next time you try to double your portions.

Does searing a steak really seal in its juices?

Many cooks will tell you that searing your meat ensures all the good juices stay inside. That's not quite true. While you're searing a steak on a high temperature, you're making a crispier crust on the steak, but that crust isn't responsible for keeping in any liquids.

"Nothing about making a crust on the outside of a steak is going to trap moisture," Souza said. In fact, he said, muscle proteins at higher temperatures actually squeeze out liquids instead of keeping them in.

What's the best way to preserve nutrients when cooking vegetables?

The best way to preserve and enhance the nutrition in fresh broccoli is to steam them, according to a November 2015 study that evaluated different cooking methods for vegetables, including broccoli. 

One of the easiest ways to steam? Fill a large glass bowl with broccoli, add a tablespoon or so of water to the bowl, cover the bowl with a plate, and then microwave your setup on high for a few minutes. 

 

What does marinating do to meat?

Marinades have been a longtime staple in cooking as a way to add different flavors to a piece of meat. Typically, marinades contain some form of an acid, which reacts with the meat and breaks down some of the protein to make it more tender - too much though, and it will become mushy. 

Marinating is a critical step to healthier grilling: Studies have linked marinading your meat to fewer HCAs (an ingredient that's been identified as potentially carcinogenic) being formed during the cooking process.

Pro tip? Try hacking the pH levels in your marinade by tossing your meat in baking soda and salt, letting it sit, then marinating it per usual. This helps the meat brown and hold water better. 

What makes cakes turn brown?

Speaking of baking soda - otherwise known as sodium bicarbonate - it's one of the reasons your cakes turn brown. The compound is used to help cakes rise by replacing the lengthy process that yeast takes.

When it's added to the batter, baking soda reacts with any acids (think: vinegar and baking soda volcano) and creates carbon dioxide that puffs up the batter. Baking soda is also a major factor in how brown your cake or cookies turn - a pale, dense cake could signal that it's the forgotten ingredient.

What's the best way to boil pasta?

Although it's much disputed, most chefs agree: You should start with cold water. Then, for flavor, add salt, and bring it to a boil. 

Once you add your pasta, there are a few ways you can keep it from boiling over: first, leave the lid off. If that's still not doing the trick, try placing a wooden spoon across the top to break up the bubbles. Try not to add olive oil to your pasta while it's cooking. While it'll help dispel the bubbles, it will also make it harder for your sauce to stick to your pasta in the end. While it's boiling, avoid clumping by stirring frequently. 

Why do some people put vodka into their pie crust?

A few years ago, the chefs at America's Test Kitchen changed the game when they started using vodka in their pie crusts in addition to water.

The idea is that alcohol can't form gluten (which is the elastic substance you get when you mix wheat flour with water that can make pie dough tougher). When the pie baked, they noticed that the the crust was flakier and didn't taste like alcohol because it had all evaporated. 

What makes spicy foods spicy?

I have to admit: I can't tolerate even the tiniest bit of heat. The heat from virtually all peppers comes from a chemical called capsaicins. In your mouth, it binds to a receptor that registers the interaction as pain coming from heat.

The receptor isn't unique to your mouth, which is why those capsaicins can sometimes get in your eyes (not a pleasant experience). Because your body's in pain from the heat of the spicy food, it releases endorphins that acts as a painkiller, which is why some people (not me) enjoy eating the spicy foods.

Why does dough sometimes become really tough?

Remember that gluten we mentioned in the pie crust? It's also responsible for all the binding that goes on in your other baked goods (unless you adhere to a gluten-free lifestyle). The reaction happens when wheat (or barley, rye, etc.) flour meets up with water, via either stirring or kneading. And you can work the dough too much.

If you stir too much, you activate too much of the gluten and your muffins will come out too tough, with big bubbles throughout, and super high peaks instead of a rounded top. 

Does turkey really make you sleepy?

That sleepy feeling you get after Thanksgiving dinner? You can't actually attribute it to the turkey you just inhaled. It's a myth that's been de-bunked numerous times: like milk, turkey contains a chemical called tryptophan, which our our bodies convert into the sleep-influencing brain chemical serotonin.

But as it turns out, turkey (and milk for that matter) doesn't have all that much tryptophan. In milk, you'd need 10 times more to help you fall asleep. It may have a lot more to do with all the over-eating you just did

What's happening when you whip up egg whites?

If you've ever made a meringue, you've seen the magical transformation that takes runny egg whites and sugar and turns it into stiff peaks of white goodness. Egg whites are predominantly made of water and protein.

Those proteins, as Smithsonian explains, are built out of amino acids that are either attracted or repelled by water. When you add air through whipping it up, those amino acids start to separate out, creating bubbles coated in these proteins. That's when the sugar comes in and helps them keep their shape even after the whipping stops.  

What causes meat to turn brown?

You can attribute the different colours of meat to myoglobin, a protein that's found in muscle tissue. The change from red to brown has to do with its oxidation process. Dark meat tends to have more myoglobin than light meat, as seen by its pink colour.

However, doneness can't always be judged by colour (sometimes, pink meat is still cooked correctly), so it's important to measure the temperature of the meat you plan to eat. The USDA says an internal temperature of 160 degrees Fahrenheit (71 degrees Celsius) is good for ground beef, for example.

This article was originally published by Business Insider.

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