Interview With Food Scientist Guy Crosby

We recently discussed with Guy Crosby (PhD, CFS), a prolific food and cooking scientist, about the current state of play in the field, the possibilities and worries created by science, and where we are heading.

 Food scientist Guy Crosby is the science editor of  America's Test Kitchen .

Food scientist Guy Crosby is the science editor of America's Test Kitchen.

Food science and technology seem to have gained a firm foothold in our food system as solutions to pressing problems of production, undernourishment and world hunger. Over the last twenty years, cooking science and molecular gastronomy have also made their way in the professional kitchen and, most recently, in culinary schools' curricula. Witness, for example, the popularity of America’s Test Kitchen, a PBS television cooking show which applies science to fine-tune recipes, and the Bachelor's degree in Culinary Science at the Culinary Institute of America. So, is science colonizing our food world?

We recently discussed with Dr. Crosby about the current state of play in the field, the possibilities opened and challenges posed by science. Dr. Crosby's professional career as food scientist in the food industry spans three decades. He is currently the science editor for America’s Test Kitchen, publisher of Cook’s Illustrated, as well as producer of the popular PBS television program America’s Test Kitchen, hosted by Christopher Kimball. Dr. Crosby is also an adjunct associate professor in the Department of Nutrition at the Harvard School of Public Health where he teaches a course on food science and technology. So, we asked him about the possibilities and challenges of biotechnology, including the hotly debated GMOs, as well as about trends and developments in food and cooking science and culinary education. We also took the opportunity to ask him to give us a few tips on cooking success and healthy eating, and whether he thinks that science takes the poetry out of cooking.

INTERVIEW with Dr. Crosby by Symposion Journal

SJ: What sparked your interest in food and cooking as a scientist? How did it all start?

GC: Many years ago, when I was quite young, I fell in love with organic chemistry, and to this day I am still fascinated by it. Organic chemistry is often described as “cookbook chemistry” because the methods of preparing organic compounds in the laboratory are not too different from cooking food in the kitchen. When I was in graduate school I worked on the chemistry of cholesterol and started thinking about the chemistry of food, because I realized I knew almost nothing about it, and thought I should. Back then I was a very poor cook. I remember the first time I roasted a chicken for my new wife in our small apartment, and didn’t realize the gizzard, neck, and liver were in a small bag still inside the chicken! When we went west to Stanford University on a postdoctoral appointment I met other students who loved to cook and drink wine, and we formed a cooking club. We watched Julia Child on television for inspiration. This got me hooked on cooking. While in California my wife and I would save our money and go to some of the finest restaurants in San Francisco almost every month that we could afford it. Alice Waters was just getting stared across the bay in Berkeley. We learned what good food was all about. Then, I got a real job working with a startup company developing new food ingredients, so I was able to apply chemistry to my new profession, and continue to eat at good restaurants and cook good food. Life was good. Food and cooking are all about chemistry!


SJ: Do you believe we could have an applied science of cooking where chefs train to be scientists-practitioners who produce perfect meals and flavours?

GC: Yes! It is already happening. The Culinary Institute of America in Hyde Park, NY has started a bachelor’s degree program in culinary science. They realize the need for more science in cooking, especially as chefs are being required to scale-up recipes for large groups of consumers. Imagine trying to consistently produce 50 gallons of béarnaise sauce without some knowledge of the science of emulsions. Other cooking schools are also introducing science courses in their programs as they see the need for students to understand more about the science of cooking. At the same time, I meet food science students who want to apply their knowledge of science to cooking. And public school teachers are searching for ways to teach science and math through food. So scientists, chefs and teachers are beginning to work together to advance the science of cooking.


SJ: Some worry that science in the kitchen affects the romance of traditional cooking, of the chef as artist and craftsman. Do you worry too, that an applied science of cooking could bring the end of cooking as we know it?

GC: Definitely not! One of the things that got me so interested in studying organic chemistry was my fascination with all the aesthetics of the laboratory: The equipment, chemicals, smells, and beauty of the intricate glassware used for preparing organic compounds. And I could picture the 3-dimentional structures of molecules in my head. Even today I love to visit chemical laboratories. Before I became interested in chemistry I wanted to be an artist. To me there is great art in science and food, and cooking is the perfect blend of the two. Both science and cooking allow the expression of great creativity, and this will not change.


SJ: Do you agree with those who argue that a return to small, local farms—such as locavorism and the farm-to-table movement—is the answer to problems created by big agriculture?

GC: No! I think small, local farms are great for the farmer and cook, and the environment. In the United States only 0.6% of all farmland is dedicated to organic farming (as one form of farming that is often small and local). Small, local farms cannot economically feed the world’s growing population, especially in poor developing countries. For almost ten years I worked for an agricultural products company and was able to see how big agriculture works, and I appreciate what it takes to grow food on a really large scale to feed people around the world. But as a home cook and scientist, I also appreciate the value of small, local, sustainable farms. My wife and I visit our local farm about two times per week. We have to find ways of combining the productivity of big agriculture with the desire for local, sustainable farms. An organization called the Sustainable Food Lab in Vermont is taking the right approach to accomplish this. If you are not aware of this organization, I recommend you learn more about it.


SJ: Cooking with local ingredients has now become a major trend. In your writings you discuss the idea of ‘Terroir’, namely, that a local environment imparts a unique quality and taste in a product. Does science support this idea?

 Food scientist Guy Crosby

Food scientist Guy Crosby

GC: Absolutely! But if you dig into the scientific literature there is not much there in terms of really good examples, other than for wine. What really got me interested and convinced in the science behind terroir started with a simple taste test at America’s Test Kitchen a few years ago. They were evaluating commercial cannellini beans, both dry and canned. They evaluated cooked dry beans from a number of sources and asked if I had any insight into the order of taste rankings (which they didn’t disclose). I suggested they send the dry beans to a lab to analyze for the calcium content of the beans, thinking there may be a relationship between the calcium content, strength of pectin in the cell walls, and the texture of the cooked beans, which in turn might correlate with the taste rankings. When they received the results from the lab they asked me how I would rank the tasting results, which I did from highest calcium levels to the lowest levels. They were absolutely right on! The beans with the highest calcium levels received the highest taste ranking (best texture), and right on down the list. In fact, there were two sources of beans that tied for fourth place, and they turned out to contain the same amount of calcium! As it turns out the uptake of calcium from the soil by the beans is a regulated process. And beans grown in soils with high calcium content take up more calcium. So there was a direct relationship between the calcium content of the soil where the beans were grown (terroir) and the taste quality of the beans. Is it any wonder that most cans of beans contain calcium chloride as an added ingredient? I wrote about this example of terroir on my website:

SJ: You recently organized a Symposium on ‘Trends in Cooking Science’. Do you identify any upcoming trends and developments in the field?

GC: As noted earlier, there is a growing emphasis on applying science to cooking education. Two speakers at the symposium work with the Culinary Institute of America. One of them, Dr. Christopher Loss, spoke about the new program he helped to develop on culinary science, while Dr. Ali Bouzarri gave examples of how he applies science in the restaurant kitchen. Jeff Potter followed this with examples in the home kitchen. Another speaker, Dr. Cesar Vega, talked about the future of cooking science, and the need for more funding and research on cooking science. Harold McGee led off the symposium with a wonderful review of the recent history of cooking science. So, in summary, some of the trends and developments are in education and communication about how we can blend the knowledge of science with the art and creativity of cooking. Last evening I heard a lecture by Dr. Hervé This, who organized the first conference on molecular gastronomy. He spoke about his latest concept of “note-by-note” cuisine, which is creating new foods from the basic components of pure proteins, fat, polysaccharides, water, and flavor compounds. It is being applied by some of the very top restaurants in the world. This could be a trend of the future.

 Some of the top figures in cooking science at lunch following the Symposium "Trends in Cooking Science", organized by Dr. Crosby, and held on 10 August 2014 at San Francisco, CA. Starting on the left front and moving around the table clockwise are: Jeff Potter, Terry Acree, Christopher Loss, Ali Bouzari, Kathryn Deibler, Cesar Vega, Guy Crosby, and Harold McGee.

Some of the top figures in cooking science at lunch following the Symposium "Trends in Cooking Science", organized by Dr. Crosby, and held on 10 August 2014 at San Francisco, CA. Starting on the left front and moving around the table clockwise are: Jeff Potter, Terry Acree, Christopher Loss, Ali Bouzari, Kathryn Deibler, Cesar Vega, Guy Crosby, and Harold McGee.

SJ: You recently said in an interview that “Searing does not trap or keep moisture inside a piece of meat; it’s an old kitchen myth.” Could you please share with our readers two more kitchen myths that you have busted as a scientist?

 GC: One myth is that “oil is hotter than water”. Yes, we fry foods in oil at much higher temperatures than water boils, but that doesn’t mean that oil actually contains more heat energy than water. You see, heat and temperature are not the same thing. If we heat oil and water to the same temperature, say 74°C (165°F), the water actually contains more than twice as much energy as the oil. That’s because water has a higher heat capacity than an oil such as olive oil. It takes more than twice as much energy to heat water from room temperature to 74°C than it does olive oil to the same temperature. To prove this, simply drop raw eggs into separate pans of water and olive oil heated to 74°C and watch what happens to the eggs. I won’t tell you, but you can go to my website www.cookingscienceguy to see pictures of the result.

Another myth I like to bust has to do with cooking meat. Many people believe braising meat, that is, cooking it in a liquid, makes the meat more moist. Not so. Research has shown that the amount of moisture that remains in cooked meat is directly related to how much the muscle fibers shrink, because that is where most (about 85%) of the water is located. How much the muscle fibers shrink is directly dependent on the temperature of the meat. So, if the meat is cooked to an internal temperature of 65°C (149°F) it will lose a certain amount of moisture as the muscle fibers shrink and squeeze out water, whether it is cooked in a liquid such as wine, or roasted in the oven. It does not depend on how the meat is cooked. It all depends on the internal temperature of the meat. That’s why a rare steak is more moist than a well done steak. And since moistness is perceived as tenderness, a rare steak “tastes” more tender than a well done steak.


SJ: Do you share the worries of those writers and filmakers who predict a dystopic future of total control of the food system by corporations, a totalitarian biocracy aided by biotechnology and engineering, environmental disasters, etc.? What values and rules should drive food science and biotechnology for a better future?

GC: That’s a very provocative question, but one I am happy to discuss. Human needs and human values should drive the future developments of food science and biotechnology. I believe they largely have until now, and will continue to drive the future. Let’s remember that big corporations are made up of ordinary people. I know because I worked for one of them for almost 17 years.  The great scientist and Nobel Prize winner Dr. Norman Borlaug started the “Green Revolution” in the 1940’s with his research that dramatically increased the yields of wheat and rice in developing countries. It is said he literally saved a billion lives from starvation. Unfortunately, today many decry his developments for the harm they have done to our environment. Much of the debate about providing enough food to feed the world and protecting the environment has become very political. I think much of this goes back to Earl Butz, Secretary of Agriculture in the US during the early 1970’s. Secretary Butz advocated changing the so-called “US Farm Bill” so farm subsidies would be based on how many acres a farmer planted, thus reducing the cost of food and creating big agriculture. Today, we have similar policies about growing corn for ethanol for use in fuel. Almost 40% of the corn produced in the US last year was used for making alcohol mandated for fuel. Is it any wonder that the number of acres of corn planted last year were almost as many as in the entire state of California! Very little of the corn we produce actually goes into food. And it is not just in the US, but most of the developed world employs food subsidies to protect agriculture in their countries. People around the world must demand of their political officials that the fruits of food science and biotechnology be utilized for human good and the good of the planet.


SJ: What would be your three useful science tips for chefs?

GC: For chefs these tips are probably obvious, and more appropriate for home cooks. First, check the temperature of the food. Use some kind of devise for accurately measuring the temperature of food to tell when it is done just right and safe to eat. Accurate measurement of weights and volumes is also very important in cooking. Use a scale to measure the weight of food, especially when baking, but also for most food preparations (As my wife will confirm I’m guilty of not following my own advice on this one). Finally, pay careful attention to the food as it cooks. Don’t be distracted while you cook. It is so easy to suddenly overcook a vegetable or piece of meat sautéing in a hot pan, or reducing a liquid by overheating, or forgetting to remember when something went in the oven. If a little care is taken while cooking I don’t think it is necessary to religiously follow a recipe to produce good food. Planning in your head the steps of what you are about to do and getting the timing right is more important.


SJ: Our food system is efficient but hunger and environmental degradation persist. Some argue that genetically modified foods can feed us all at low cost in a sustainable way. Are these foods safe for us and the environment, and are they nutritious? If not, are there alternatives?

GC: Despite what many people think, in the US the FDA, USDA, and EPA have taken rigorous steps to ensure that genetically modified crops are safe for human consumption and the environment. An extensive review of the safety of GM crops during the past 20 years was published last year in the Journal of Agricultural and Food Chemistry. No reports of ill effects from consumption of foods made from GM crops were found. In my opinion they are safe for human consumption. Big agriculture has always had a big impact on the environment, especially in the use of water, and chemicals (fertilizers and pesticides). The only significant environmental issue to surface in recent years related to GM crops has been the development of herbicide resistant weeds, because the GM crops rely on the use of such a small number of herbicides, especially glyphosate. Crops produced from GM seeds are just as nutritious as non-GM crops. And some are now engineered to be even more nutritious, such as high oleic acid soybeans. Three large studies conducted at top universities in the UK and US showed there is no evidence that organic food is more nutritious, or reduces the incidence of 16 different cancers studied in a large cohort of people consuming predominantly organic food. Organic food does provide less exposure to chemical pesticide residues. Today, GM crops are grown in 22 different countries, with more of them in developing countries. GM crops could help developing poor countries, especially in Africa, but largely political reasons prevent them from growing GM crops with improved yields that are tolerant to heat, drought, and salinity. For those who want to read more I encourage you to read the excellent books by professor Michael Gibney with the University College Dublin called “Something to Chew On-Challenging Controversies in Food and Health” (2012) and the one by professor Robert Paarlberg with Wellesley College, entitled “Food Politics-What Everyone Needs to Know” (second edition, 2013).


SJ: You recently lectured on Mediterranean diet. What would you like to say to those who missed the lecture? Is Mediterranean diet a healthier way of eating?

GC: I believe it is. Unfortunately, many of the countries in the Mediterranean region are beginning to adopt a western-style diet. The predominance of vegetables, fruits, legumes, nuts, seafood, olive oil, and some wine, while limiting saturated fat, dairy products and meat, especially red meat, and simple carbohydrates in the diet, along with a good level of physical activity (which makes it a Mediterranean life-style as opposed to diet) are important for health. Many studies support the value of a Mediterranean life-style. My wife and I try to follow it to a fair degree, but also like other cuisines such as Asian, French, Mexican, and California-style cuisine, and good old New England cooking (splurging on fried clams and boiled lobster on rare occasions). We tend to avoid fried foods, hamburgers, pizzas, and desserts, but give in now and then. Everything in moderation!


SJ: Finally, a more personal question. What are your future plans ? Do you have any specific projects under way? Would you like to share them with our readers?

GC: I still teach a course on food science and technology at the Harvard School of Public Health, and plan to keep doing it for a while longer, probably as long as I hold my Adjunct Associate Professor position with the Department of Nutrition. This academic year (and hopefully next) I am mentoring a postdoctoral student from Brazil. I am beginning a new book to follow the one I co-authored on “The Science of Good Cooking” (2012). I will continue to work as the science editor with America’s Test Kitchen, and give lectures now and then, mostly on cooking science and science in the kitchen. I have a few old vintage Porsches that I love to drive on sunny days. My wife and I have two grown children who were born in California and are very successful (neither one in science), and a wonderful granddaughter. And of course, we return to California every now and then to relive our younger years where it all started!

 Food scientist Guy Crosby

Food scientist Guy Crosby

Guy Crosby (PhD, CFS) is the science editor for America’s Test Kitchen, publisher of Cook’s Illustrated and Cook’s Country magazines, as well as producer of the popular PBS television program America’s Test Kitchen, hosted by Christopher Kimball. He is co-author of the new book “The Science of Good Cooking”, published by America’s Test Kitchen. Guy is also an adjunct associate professor in the Department of Nutrition at the Harvard School of Public Health where he teaches a course on food science and technology.


Guy was born and raised in Massachusetts and obtained his BS degree in chemistry from the University of New Hampshire, and PhD in organic chemistry from Brown University in 1969. This was followed by two years as a postdoctoral research associate in the Department of Chemistry at Stanford University. He began his professional career with a small startup company in Palo Alto developing new food ingredients. After twelve years in California he and his family moved to Princeton, New Jersey to work with the Agricultural Products Group, and then the Food Ingredients Division of FMC Corporation as Director of Research and Development. In 1996 Guy relocated to Bedford, Massachusetts to serve as Vice President of R & D for Opta Food Ingredients. After retiring in 2002 Guy was appointed an associate professor at Framingham State University, where he taught until 2011. He continues to teach food science at the Harvard School of Public Health.

Guy is a professional member of the Institute of Food Technologists, the American Chemical Society, and the American Society for Nutrition. He is also an external advisor for the EcoGastronomy program at the University of New Hampshire, a member of the Food Task Force for Boston’s Museum of Science, and a Food Science Communicator for the Institute of Food Technologists. On April 1, 2013 Guy was officially included in the first group of Certified Food Scientists (CFS) approved by the Institute of Food Technologists.

You can learn more about Guy at


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