Shirley O. Corriher

The kitchen scientist

By
March 3, 2009

Shirley O. Corriher combines a background in biochemistry, an appreciation of good food, and a raconteur’s ease with anecdotes to help cooks both budding and expert understand the science behind cooking.

In addition to writing two cookbooks — 1997’s CookWise and last year’s BakeWise — Corriher has traveled the world teaching cooking workshops, consulted for food companies, and appeared on the Food Network’s “Good Eats.” She spoke with Culinate about testing recipes, the science behind a smooth ganache, and how to make your muffins peak.

You started your cooking career as the owner of a boarding school. Did you have a passion for cooking before then?
No. I was very, very busy. I finished high school in three years and really worked my tail off in college. Immediately after college, I got a job as a research chemist to support my husband through graduate school.

I did cook, and I had a good time trying a new recipe. And I guess I knew a little bit more than some of my other friends; I can remember a nurse friend of mine breading a fish, and she was tearing up pieces of bread and pressing them into the fish. At least I knew that wasn’t right.

But the boarding school was truly a trial by fire. I had a big aluminum skillet, and I’d crack a dozen eggs into it and put the pan on the heat, and then stand there and scrape like crazy. What I’d end up with was this knotty mess.

shirley o. corriher
Shirley O. Corriher

The two boys that the school started with would complain, “You’re starving us!” And I’d say, “That’s six eggs apiece!”

Admittedly, about half of the eggs were stuck to the pan. See, when you put liquid protein into a pan, it’s going to ooze into the surface any way it can, and when you heat it up, you are literally cooking the food into the pan.

Thank heavens my German mother-in-law came to visit. She taught me to heat the empty pan first, and then put in a little oil or butter and twirl it around to coat the bottom, and then put your eggs in.

One of the most important things she taught me was not to touch; you have to let the surface of the eggs coagulate, and then you can gently slide them away. They are no longer stuck once they cook. And they just puff incredibly beautifully.

That was my first major learning experience about letting things cook, and then they will release themselves.

In BakeWise, you talk about making biscuits with your grandmother. Do you have any other enduring childhood food memories?
I used to follow my grandma around the kitchen before I started school. My two uncles and my aunt all lived there, and my grandfather too. So she had five adults to feed three meals a day. And my two uncles worked outside (one was a postman and the other delivered groceries), so they could put away the food.

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My grandmother didn’t get her chicken at the grocery store. She had to wring their necks and singe them and pull the feathers and the whole nine yards. She made biscuits three meals a day and cornbread twice a day for lunch and dinner.

And she had a huge garden, so she always had several vegetables. In season, there would always be a plate of sliced tomatoes and a bowl of cucumbers and onions in vinegar on the table in addition to everything else. I guess I grew up taking a lot of good food as a given.

How many different iterations of a recipe do you test before you consider it final?
Sometimes it’s just exactly like I like it the first time. But other times, you just have to do it over and over again.

For example, I wanted to do a flourless chocolate cake because I think people can really see what an ingredient does when they do something without it. I thought, “OK, I don’t need to reinvent the wheel, I’m just looking for an example of a flourless cake.” So I looked on the Web and I looked at dozens of recipes, and basically they were nothing but semisweet chocolate and eggs. Most people added a stick of butter, and some people added sugar. But it was essentially 16 ounces of chocolate and 8 eggs.

Why are some flourless chocolate cakes dry and some moist?

So I combined 16 ounces of melted chocolate and a stick of butter and 8 eggs. It looked just fine going into the oven. It set just beautifully. And I cut a slice, and aaaahch! It was the driest thing I’ve ever put in my mouth.

I knew perfectly well it was all those egg whites, which are major drying agents. I thought, “Heavy cream is wonderful; it makes things really moist. Why don’t I just substitute half a cup of heavy cream for that half a cup of butter?” So I did that, with my 8 eggs and my 16 ounces of chocolate. Well, this cake did not set and did not set and did not set. I had chocolate pudding.

I knew that eggs have to be a little bit acidic to set, and cream is non-acidic. (The acidity was coming from the semisweet chocolate, which has a pH of about 5.6.) Then I realized that cream is only about 40 percent fat; the rest is dairy product.

Dairy products contain chemicals called buffers that soak up acidity or alkalinity to keep the substance at right about neutral acidity. (A little baby calf could be harmed if a cow’s milk changed with everything it ate, to become really acidic or really alkaline.) The buffers in the cream had gobbled up the little bit of acidity that was there from the chocolate and the mixture wasn’t acidic enough for the eggs to set.

I think I ended up using just a little cream so it wouldn’t gobble up all the acidity, and I reduced some of the egg whites to get a moist cake. I don’t know how many times I made the cake.

What’s the biggest mistake you think home cooks make that could be rectified with a little scientific knowledge?
The number-one biggest problem is over-leavening. And this is not the home cook’s fault; it’s the recipe’s.

There are basic rules of leavening: 1 to 1 1/4 teaspoon baking powder per cup of flour (I stick right to one teaspoon baking powder per cup of flour) and 1/4 teaspoon baking soda per cup of flour (there’s already 1/4 teaspoon baking soda in a teaspoon of baking powder).

How can you ensure baking muffins with pointy tops?

People just don’t realize how potent baking soda is. You may have a recipe with two cups of flour and the recipe has some buttermilk or sour cream, so the person writing it thought, “Well, I need some soda to neutralize that.” So their recipe will have 1 teaspoon baking powder because it’s so reliable, but then they’ll call for something like 1 teaspoon baking soda.

Now that’s enough soda to leaven five cups of flour, instead of the two cups you have. And when you have too much leavening, the bubbles run into each other, get huge, float to the top, and pop. And there goes your leavening.

You’d think that too much leavening would make something rise too much, but it’s just the opposite.
That’s right. Another problem for home cooks is muffin recipes that are baked at too low a temperature. If you want a peak on a muffin, you’ve got to have the outside of the muffin set while the inside is still juicy and rising. And that’s probably not going to happen in a little muffin until, ideally, about 400 to 425 degrees.

Those muffin recipes that are baked at 350 degrees? The only way they will work is if they have too many eggs, and then they will be just chalky dry. You can get a peak at 350 with too many eggs, but it’s not gonna be nice.

You frequently come up with creative innovations, such as using whipped cream in pound cake. What do you consider your most unusual finding?
Most of the time, classic cuisine is really based on science. But sometimes I find a classic way that worries me because it’s a risk for not turning out right.

The one thing that has bothered me through the years is ganache. The classic way to prepare it is to chop the chocolate really fine, bring the cream to a boil, and then pour the cream over the chopped chocolate.

bakewise

But when you work with chocolate, one of the big problems you encounter is what’s called “seizing.” You have this rich, luscious, smooth melted chocolate, and all of a sudden it becomes this solid, grainy rock.

If you dip your coffee-stirring spoon into your sugar bowl day after day, little hard grainy knots will appear in your sugar, because each time you dipped, you added a tiny bit of moisture to those dry particles, and the dry particles glued together.

So any time you pour a liquid into chocolate, for a split second you have a lot of chocolate and a tiny bit of liquid, and some of the chocolate particles can get glued together. Thus the seizing.

The way I’ve always made ganache is to heat the cream barely to a boil in a wider pan — not a narrow saucepan but a wide saucepan, or even a frying pan that would give me some surface area. And then I would dump all of the grated chocolate on top. That way I was sure that I had more liquid than chocolate most of the time. That’s one of the more radical things I’ve done.

How do you integrate the sensual side of food — the smells and textures and tastes — with your more formal knowledge of the science behind making good food?
See, if you know a little science, it makes your life so much easier. You’re free to go wild with other parts of putting the food together.

If you know the only thing you have to do is be patient and let the food cook before you try to turn it, then you’re free to add whatever liquid you want. You’re free to add whatever spices or herbs you want.

I think it just gives you an enormous amount of confidence, and you don’t have to worry about messing things up. You know it’s going to come out all right.

Miriam Wolf writes about books and food for various publications, and is the former managing editor of Bitch magazine. She lives in Portland, Oregon.

Related recipe: Papa Haydn’s Chocolate Gâteau; recipe: Banana Muffins

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1. by Sophia Markoulakis on Mar 3, 2009 at 6:01 PM PST

Fantastic, informative interview. We don’t hear enough about the science of recipe development—loved that angle of the article. She sounds like a wealth of knowledge.

2. by Carrie Floyd on Mar 4, 2009 at 10:43 AM PST

I always wondered why some muffins have that nice dome and others practically sink. I love reading about the why and how of cooking, both successes and failures. Thanks for the great interview.

3. by Brave Sir Robin on Mar 4, 2009 at 2:39 PM PST

Great article!!!!!!

I love the fact that she tells us why a recipe works, not just that it will.

4. by Ramona Fahlbusch on Mar 16, 2009 at 4:00 PM PDT

I had the pleasure of sitting at dinner with Shirley last week. She is a wealth of knowledge and is an entertaining speaker. I admire all that she knows and hope that one day I will know half as much of the science behind the recipe.

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