This Is The Science Of Yum

It can be tricky to describe the “mmmmm…” wave of deliciousness that coats the inside of your mouth when you slurp from a bowl of ramen, or take a bite of pizza or dry aged steak. If words like “savoury”, “brothy” and “mouthwatering” come to mind, we’re likely talking about umami — the elusive fifth taste which transcends cooking techniques, recipes and ingredients to make food universally yummy.

Umami may be why you see more pizza and burger joints opening every year, and why vegetarian ramen is the new food trend for 2020. Ken Yamada, founder of UK-based ramen chain Tonkotsu (which operates 12 shops arond London, with three more slated to open this year), says that his vegan ramen is every bit as good as a bowl made with traditional pork broth.

But What Is Umami?

Japanese chemist, food lover and Tokyo Imperial University professor Kikunae Ikeda coined the term from “umai” (a casual reference to “delicious” in Japanese) in 1908 after noticing that the taste of kombu dashi, a seaweed broth, was distinct from the four basic tastes of sweet, sour, salty and bitter. He demonstrated that while protein has no flavour, as it breaks down into glutamate via cooking or fermentation and attaches to taste receptors on our tongue, things start to taste really good.

Ikeda wasn’t the first to notice this effect. Garum (fermented fish sauce) was popular in ancient Rome. Murri, a fermented barley sauce, was used liberally in medieval Byzantine and Arab cooking, and fermented fish and soya sauce have been staples of Asian dishes since the third century. In the late 19th century, chef Auguste Escoffier, widely considered the father of modern French cuisine, had an inkling that his cooking was so well received because of a fifth taste present in his veal stock. Although he didn’t understand how or why, Escoffier knew it was quite literally his secret sauce for success.

In 1913, Shintaro Kodama, a disciple of Ikeda, discovered that dried bonito flakes contained another source of umami: 5’-guanylate. Four decades later, Akira Kuninaka noted that guanylate in dried shiitake mushroom also delivered the umami taste.

Kuninaka quickly made another connection: inosinate (found in abundance in meat and fish) and guanylate (often derived from vegetables and dried mushrooms) generate a more subtle umami taste than glutamate, but when combined, they deliver an “umami bomb”. A glutamate to inosinate ratio of exactly 1:1 delivers up to eight times the intensity of umami than either glutamate or inosinate on its own.

Most chefs’ achievement of umami synergy is derived from experience rather than by design. If you test an ichiban (or primary) dashi made with kombu and bonito at any Japanese restaurant, the levels of glutamate and inosinate will be equal because that’s what tastes best. It’s why the Scots combine leeks and other veggies with chicken in cock-a-leekie soup, and why we crave the Italian combination of ripened tomato, aged parmesan and mushroom.

“We use umami all the time in our cooking, although it’s not always intentional and sometimes happens subconsciously. We incorporate ingredients like country ham, dried seafood, preserved vegetables, seaweed, dried tomatoes and cheese rinds,” says Will Aghajanian, former head chef at The Catbird Seat in Nashville, a tasting menu restaurant and culinary talent incubator in the US, which was named one of the most important restaurants of the last decade by Esquire.

Chefs have lots of room to experiment as the list of foods that yield umami is long and appetising: shellfish, cured meats and meat extracts such as broths or bouillon, mushrooms, vegetables, green tea, and fermented and aged products involving bacterial or yeast cultures — think aged cheeses, shrimp paste, fish sauce, soya sauce and products made with yeast extracts like Vegemite and Marmite.

Human breast milk and even amniotic fluid are high in glutamate, likely priming us to seek umami throughout life.

There Are Health Benefits To Consider Too

Boosting umami lets you cut the amount of salt used in a dish by up to 30 percent without compromising the palatability of the dish — great news for anyone trying to follow a low-sodium diet. Dishes rich in umami require less flavour-carrying fat such as butter and cream, which means the calorie count can be reduced by up to one third without impairing our enjoyment of the meal.

Glutamate stimulates the throat, roof and back of the mouth, as well as receptors in the stomach, where it triggers the body’s response to digest and absorb protein.

And because umami is mouthwatering, quite literally — studies in taste physiology show that glutamate and inosinate promote salivation — it can help the elderly produce enough saliva to register more flavour and better digest foods. This improves their quality of life and reduces risk of malnutrition.

While you can make an umami-rich dish in today’s kitchens relatively quickly, it’s important to remember that those ingredients have been carefully processed over time. Beef takes a long time to raise before it can be harvested, and enzymes must break down the meat to generate flavour. When making a broth from katsuobushi (or bonito flakes), the skipjack tuna is carefully selected for quality, run through two types of fermentation,

dried and then smoked. Even a slice of raw fish, served with wasabi and soya sauce, is far from simple: the soya sauce took nearly a year to produce, the fish took several years to mature and the wasabi most likely came from a farm fed by a pristine mountain spring.

Chef Ken Tominaga, a Tokyo native who runs Pabu Izakaya and The Ramen Bar in California with chef Michael Mina, pursues umami through special cooking techniques.

“We clean our chicken really well before making stock, and when the umami gets to a peak flavour, we stop cooking. Timing is very important,” explains Tominaga.

“[Not everyone] truly understands umami and the authentic taste behind it. Often I see people adding more soya sauce to their ramen, whereas in Japan, the taste would already be strong and intense enough how it is.”

That said, commercial products which act as a shortcut to umami have been produced in Japan since Ikeda’s discovery. In 1908, Ajinomoto Co. was created so that Ikeda could synthesise and sell the seasoning monosodium glutamate (MSG), a sodium salt of the common amino acid glutamic acid.

MSG, also known as food additive E621, is often used with disodium inosinate (E631) and disodium guanylate as disodium 5’-ribonucleotides (E635) to enhance the flavour of ready-made foods and snacks. It’s said that a mixture with 98 percent MSG and two percent E635 has four times the flavour-enhancing power of MSG alone. While some claim to be allergic to MSG, there have been no conclusive evidence to date to prove a connection.

“MSG dissolves easily and does not overpower other flavours, which makes it a useful food ingredient. Not only does MSG give dishes a savoury, umami taste, but it is considered to be the purest form of umami,” says Tominaga.

Other Entrepreneurs Have Cooked Up Their Own Shortcuts

At US-based gourmet burger chain Umami Burger, founder Adam Fleischman developed “natural flavourings” from seaweed, cheese and dried fish, which he branded as Umami Master Sauce, Umami Dust and Umami Spray. These are added to burgers after cooking.

Chef David Nayfeld — formerly from New York’s Eleven Madison Park and Joel Robuchon’s The Mansion at MGM Grand in Las Vegas before opening his own Italian taverna Che Fico in San Francisco in 2018 — says he adds “MSG” to dishes using homemade tomato paste and dehydrated mushroom powders.

“We also create reductions, bases or seasoning powders, one of which is our ‘super stock’ made of Parmigiano rinds, chicken stock reduction, mixed with dashi,” he offers.

Sounds good to me. Who’s hungry?

This story first appeared in the May 2020 issue of A Magazine.