The science of making the perfect sandwich | Canada Voices

Subway calls its employees “sandwich artists.” But to build a truly great hoagie, banh mi or BLT, you must also think like a mathematician, an architect, a physicist, a chemist. STEM will help you make memorable sandwiches.

The way meat is stacked, greens are seasoned and air – yes, air! – is manipulated can dramatically alter the way a sandwich tastes, says Helen Rosner, a sandwich aficionado who serves as the New Yorker’s restaurant critic.

“Once you start venturing into more complex or adventurous sandwich making, you very quickly become aware of the kind of material science considerations that have to go into this kind of thing,” she says.

Canada’s best sandwiches, from coast to coast

Lan Lam, a supervising producer at America’s Test Kitchen’s, agrees. She is always taking stock of the chemical properties of her ingredients and different ways to layer them.

With years of experience making, eating and analyzing sandwiches, Lam and Rosner shared their tips on how to build them better.

Ratio: Tall sandwiches are fun to look at, but challenging to eat unless your jaw is built like that of a ventriloquist’s dummy. When looking at a cross-section, Lam wants her bread to take up one-quarter to one-third of the sandwich.

Griddling: Bread needs structural integrity. A floppy slice can be fortified by griddling or toasting one side of it first, Lam suggests.

Waterproofing: Within a few minutes of assembly, bread can act like a sponge, soaking up moisture from its fillings. Lam likes to coat the inside surface of hers with fat – such as an oil-based dressing, mayo or olive oil – which acts as a light waterproof layer.

Seasoning vegetables: Salt those tomatoes and season those greens, Rosner says. “It breaks my heart whenever I see a sandwich that has obviously dry arugula thrown onto it. Taking that moment to toss your greens with a little bit of vinegar or a little bit of oil even just opens up the entire experience of the sandwich.”

Drain wet ingredients: Put tomatoes and any other wet additions (such as pickles) on a paper towel for a minute to wick away excess moisture that could make your sandwich soggy, Lam says.

Fold your meat: For sliced deli meat or gravlax, Lam folds them rather than laying each piece flat. “It’s easier to bite all the way through. You’re not pulling bits of ham out with you as you’re taking a bite.”

Function over form: On Instagram, avocado is added in shingles, because that is “the right aesthetic choice,” Rosner says, but when you’re actually consuming it, the slices are “slipping and sliding” out of place. Mashed avocado could give you a similar effect with more structural integrity.

Umami: This savoury, satisfying element is often missing from sandwiches made at home, Lam points out. A bit of soy, miso or anchovy paste – or even a slice of tomato (salted, please) – can offer a potent hit of it.

What to separate: A lot of delicate greens break down when they come into contact with oil, so if you’re preparing your sandwich several hours before you eat it, try to place those lettuces beside things that are water-based, rather than oil-based, Lam suggests.

Air: Rosner’s assertion that air is the most important ingredient in a sandwich went viral in 2024. You intentionally minimize it in a densely-packed panini, but embrace it in a sandwich built on focaccia, where those big bubbles give you a burst of yeast and salt, or an Italian sub, where airflow between stacked ingredients offer an easier, more pleasant bite.

Ingredient sequencing: That spicy mustard, horseradish or pungent cheese is better placed on the top of the sandwich, rather than the bottom, so they don’t hit your tongue first and overpower all the other flavours, Rosner says.

Embrace herbs: “I think what blows people’s minds when they have a banh mi for the first time is the huge amount of cilantro and sometimes mint or basil,” Rosner says. These tender herbs can work in other sandwiches, too. “Treating them almost like a lettuce is incredible.”