Freshly spiced

Martin works in materials development at SCHOTT, working with glass and glass-ceramics. But today, the hobby beekeeper has invited people to have a taste of his home-grown honey. In his spare time, Martin produces around 100 kilograms of honey a year, but what links his hobby with his job? “Making glass is like cooking and making glass-ceramics is like honey production,” he explains, clearly enjoying the connection.

Twin talents at the stove

Today, Martin is not working in the lab. Instead, he’s in an elegant kitchen. In the middle of the spacious work area is a black glass-ceramic CERAN® cooktop from SCHOTT. Indeed, most of the kitchen is black – even the faucet and the sink.

Joining Martin is Tanja Farwick, a food blogger from Münster, Germany who has been taking a close look at the honey connoisseur’s actions. “We could also make it more liquid with vinegar and oil,” suggests the hostess of this highly unusual cooking session. Martin nods. “But honey isn’t in the recipe at all,” he wonders. “In cooking, you have to be prepared to do something crazy,” replies Tanja. “Developing a new recipe takes courage and creativity.”

Martin smiles. He understands this from his experience in glass development. The main difference is that more can go wrong in the process of glass melting than in the preparation of carpaccio dressing. The honey pairs perfectly with the orange juice, olive oil, balsamic, and agave syrup. “Sweet flavors are always good,” Tanja says, stirring everything together. Martin has a taste and says, “I would add a little pepper.” Tanja nods. The dressing is done.

While Tanja has the home advantage in the kitchen, the live talk with Martin is unusual for her. Preferring the description chef-entrepreneur to influencer, she is also an accomplished food photographer. Despite saying “I’m neither a trained cook nor a photographer,” it’s with both skills that she earns her living. As part of the food blog Foodistas, she is creative, has a good feeling for flavor combinations, and is overflowing with ideas – as one glance at her Instagram channel makes clear. Developing new creations is everyday life for her, and she posts new recipes twice a week. However, learning how this relates to glass development is new territory.

Martin has cooked the beet and then cut it into thin slices. But the food expert pulls a joker, adding a few raw slices to the carpaccio – a crunchy surprise. “We don’t stay static with our recipes,” Tanja says. “We leave a lot less to chance in glass development,” laughs Martin.

While cooking is almost all about the flavor, glass requires a deep understanding of chemistry and physics, and many other considerations in its development. A new glass recipe starts with a specification, which means a large dose of theory. What does the glass need to do? What properties need to be ruled out? What role does uncontrolled crystal formation play, and how can it be prevented? Which process properties are important? In cooking terms: vegetarian or meat, Italian, or Asian, will the bread fit in the oven or is a bigger one needed? If the new oven is too expensive, perhaps flour from a new grind could be the answer?

“The better I know my existing data and requirements, the more likely I am to end up with a good product,” Martin says. For him, the most important sources of information at the beginning of each glass recipe are a well-maintained database, including every new trial melt, old binders, patent collections, and the expertise of all SCHOTT teams. Figures underscore just how crucial this preliminary research work is: Only around one in 20 development projects is ultimately successful.

Trials and procedures

Back in the kitchen, Tanja and Martin are chatting enthusiastically. The food blogger explains how she came up with the idea of making hummus from beets: “I mean, why not? I didn’t like beets before, so I had to prepare them in a way that I liked.” As with many succcessful recipes, this was a creative process that had many trials until Tanja finally reached her goal. In this case, Greek yogurt, date syrup, garlic, and chili flakes helped the most. Martin tries her puree and is thrilled. “It’s got an Asian flavor,” he says. Tanja grins. “That’s because the zaatar spice blend gives it an exotic taste.”

 A key tool for this process is a phase diagram. Used to illustrate states and their associated phases in materials development, it can set the components in an effective relationship and demonstrate the effects of adjusting the recipe. “We do 100 test melts to figure out the one we can use,” Martin says, “but the other 99 still took me somewhere because I learned from them.”

But in many developments, research teams are also breaking new ground. With design-of-experiments (DOE), they rely on statistical experimental design and the power of simulation. The systematic procedure helps determine the relevant influencing factors for a product from a large number of parameters. With the aid of an experimental design, these factors are varied largely independently of one another in order to derive their effects on the target variables and thus a cause-and-effect model. In the case of glass development, there are between seven and 15 dimensions that have to be taken into account.

Finally, the computer calculates a mathematical model that can be used to simulate new compositions and their properties. Only the most promising glass recipes are then replicated in practice. “Otherwise, it would be like trying to figure out an optimal baking temperature by putting the dough in the oven at a temperature one degree higher each time,” explains Martin.

A periodic table of possibilities

The glass-ceramic manufacturing process offers several optimization approaches, especially in the ceramization step. “For example, I can reach my target temperatures at different speeds in the temperature programs, or I can vary the height of a temperature level,” explains Martin. “This allows me to make extremely significant changes to the properties of the glass-ceramic.” The result, he says, is either a transparent material or, by using higher temperatures, an opaque one. “It’s like baking bread,” he says. “If a dough is baked longer, the end result is not fluffy naan, but crispbread.”

The new glass-ceramic is just one example of how SCHOTT continues to reinvent a material. And there is no end in sight. “We have half the periodic table at our disposal for improvements and new developments,” says Martin. “If you take an existing system and throw in another component, you get something completely new.” That, he says, is the great appeal of glass and glass-ceramic. In the context of cooking, salt helps seasoning, but can also change properties and preserve food. Small cause, big effect – something Tanja also understands. She chops a handful of hazelnut kernels and toasts them briefly in the pan. Together with freshly grated horseradish, she uses them to refine the beet hummus, and dinner is served. “Trial and error is important,” Martin grins. “Especially if it’s this delicious.”