Chemist's best advice: How to grill food perfectly

You can steam food, boil it, or sous vide, but all of these techniques have one thing in common: You can't get the temperature higher than a hundred degrees. This has a chemical result that has a lot to say about the taste. Boiled food does not have the same taste and cannot have the same taste as fried food.

So what actually happens when food reaches a higher temperature?

Simply put, it is an interaction between sugar and amino acids from proteins. If your temperature is high enough, you will get a series of reactions that happen spontaneously and quickly. The sum of these reactions is called the Maillard reaction, says doctoral candidate Thomas Daniel Vogelaar, of the University of Oslo.

Chefs often call the Maillard reaction “browning.” It is the Maillard reaction that produces the brown pigments. At the same time that what is being fried turns brown, good flavors also appear. The Maillard reaction is what causes coffee beans to be roasted before being ground into coffee. It is the Maillard reaction that gives cakes the goldenness and “that little something extra” when the bread is toasted. The Maillard reaction is the reason why a steak is fried at high heat first, before frying it at a low temperature for a long time. This chemical reaction is simply the essence of good cooking, but it cannot occur at low temperatures.

When does magic happen?

-Depending on how long you fry them, they get more brown and darker shades of brown. Vogelaar says the ideal temperature for the reaction is between 140-165 degrees Celsius.

Vogelaar is a chemist, with an above-average interest in food chemistry.

He explains that the Maillard reaction actually starts at 120 degrees, 20 degrees above the maximum boiling temperature, but it is better at a slightly higher temperature.

On the other hand, if the temperature gets too high, you risk two things: caramelizing and burning the food.

-At high temperatures, the Maillard reaction can compete with the caramelization process. During the caramelization process, the sugar reacts with itself, rather than with the proteins involved in the Maillard reaction, Vogelaar explains.

On the other hand, if food burns, it tastes bad. It will also contribute to the formation of unhealthy substances.

Grill King Tip: Maintain temperature control

The chemist's advice is supported by one of Norway's leading barbecue experts, Craig Whitson. He leads the Norwegian barbecue team which has won numerous awards in international competitions. His best advice is to control the heat:

– To achieve the best result, from a technical point of view, is to control the heat. You decide how much, how much, and when to use it. This is absolutely crucial, Whitson says.

However, he does not want to say that there is one specific temperature that applies to all foods. The choice of raw materials in terms of type and size is important, so he gives more general advice.

– There are hardly enough degrees on the grill to get the first short done of beef over a strong fire. I'm not a chemist, but for food I use very strong heat for a short time because I want maillard and color. The rest of the time I use indirect heat. He explains that food should not be burned, but strong heat should be used when needed.

The reason most people enjoy eating in restaurants better is because a good chef controls the heat all the time — and uses more salt, he adds.

Grill with two heating zones

Whitson recommends creating two heating zones on the grill: one for intense heat and the Maillard reaction, and the other for indirect heat where the food can sit longer.

-Heat control is the difference between very good grilling vs. good grilling. The second zone should be low-heat, this is the largest part of the grill, because most grilling should be done over indirect heat, Whitson says.

Whitson believes that strong heat should come first:

-If I'm cooking a steak on the grill, I put it on high heat first. Some do the opposite, but the best Maillard effect comes with raw protein with added salt. So I start with strong heat until I get the color I want, then I move it to indirect heat, Whitson explains.

How to improve the Maillard reaction

There are several things you can do to make the Maillard reaction easier. The only thing is to make what you want to fry as dry as possible. The water will boil and evaporate first. This means you won't get the proper Maillard reaction until the water is gone.

The first thing that happens when you fry or bake something is the evaporation of water. Only then can the food reach a temperature above 100 degrees, says Vogelaar.

Another way is to make sure what you are frying is alkaline.

The Maillard reaction occurs more easily at basic pH, so the reaction becomes faster and continues.

That's why Vogelaar has a trick for getting really crispy french fries with the optimal Maillard reaction:

– Put a little baking powder with the potatoes. This has two effects: one is that more starch is released, and the other is that the Maillard reaction occurs faster.

According to Vogelaar, you can do this by boiling potatoes in water with a little baking powder before frying them, or by applying a thin layer of baking powder on the surface. Baking powder is essential. Another type of food where this trick is used is pastries:

German pretzels are an example of the Maillard reaction. They're put in the lotion first, just like the lutefisk. Lotion is essential. This increases the pH to the point that this bread becomes almost completely black during baking, simply because of the improved Maillard reaction, says Vogelaar.

This reaction changes the texture of the surface, and you can't achieve it any other way, he says.

But why do people love barbecue?

Vogelaar has a possible explanation:

– In the same reaction, several substances are formed, including a substance with a buttery smell that we associate with fats. In previous times, people relied on eating fat and sugar because it provided a lot of energy. I think that's why we think this flavor is so good. Additionally, heat processing of food provides more nutrients, Vogelaar explains.

He says that the human brain expanded at the same time that humans began to heat food. Heat processing released more nutrients, and also meant there were fewer bacteria in the food, so we had to put less effort into fighting them.

Potatoes are an example of a vegetable that has little nutrition available before heat treatment. It's even slightly toxic. We cannot eat starch until it is processed. When it's heat-treated, you suddenly have huge amounts of energy available, says Vogelaar.

For the record: It is not the Maillard reaction that makes potatoes edible. Boiling them is fine, although many would say they are better when fried, grilled or sautéed.

Negative effects of frying and grilling food

The Scientific Committee for Food and Environment (VKM) recently released a report on the health risks of eating grilled food. There have long been warnings against eating too much grilled food, but the main conclusion in the report is that the food, not the method, is most important for health. In other words: You can grill vegetables and lean meats 100 times a year and still fall below the exposure limit for hazardous substances, according to the report.

– Is it possible to achieve the Maillard reaction without also forming harmful substances?

– It may be impossible to avoid the formation of harmful heat-treated substances when frying food. The Maillard reaction begins at about 150 degrees. We write in our report that heterocyclic aromatic amines can form at these temperatures and that it is suggested to keep the temperature below approximately 180 degrees. The academic leader of the study, Espen Mariussen, says that the amount formed will increase with increasing temperature and cooking time.

Mariussen further explains that a group of substances called polycyclic aromatic hydrocarbons (PAH) can form during the incomplete combustion of organic materials. It can happen, for example, when grilling or smoking food. Natural sources of PAHs also include volcanoes and forest fires.

– PAHs are always formed as mixtures of a number of different substances, and only a few have been subjected to toxicological risk assessment, adds Mariussen.

The report notes several uncertainties, including the lack of systematic overviews comparing the health effects of grilled foods and other cooking methods. Although there are still things we do not know about these substances, it is possible to avoid some of them, even when grilling:

– The most important thing is not to overcook the food until it sizzles and burns. You should avoid letting a lot of fat drip onto the fire until it catches fire and produces a lot of smoke that sticks to the food. Smoke may contain polycyclic aromatic hydrocarbons, Mariussen says.

The article was first published on Titan.uio.no