Why Men-Eiji's Broth Develops a Deeper Flavor Overnight

For ramen devotees, the moment a bowl of gyokai-tonkotsu arrives at the table is the culmination of hours, sometimes days, of careful preparation. At Men-Eiji, the Sapporo-based brand founded by Jun Furukawa, that bowl lands with a depth of flavour that seems almost paradoxical: how can something cooked for so long still taste so fresh? The answer lies partly in what happens once the heat is switched off, when the broth is left to rest and the ingredients continue their quiet conversation through the night.

Many ramen chefs chase intensity through aggressive boiling, but Furukawa's kitchens follow a different rhythm. The broth at Hiragishi BASE and at Duck Ramen EIJI is coaxed, not forced, into richness through long simmering followed by a deliberate pause. That pause is where the magic compounds. As the liquid cools, layers of collagen, fat and dissolved minerals reorganise into a smoother, more rounded base, and the aromatics settle into harmony. Visitors planning a trip to Hokkaido can find practical information about the restaurants and menus on the about-site page.

The quiet chemistry behind a resting broth

When broth finishes its active simmer and the flame is turned off, the liquid does not simply stop transforming. It enters a slow equilibration phase during which dissolved proteins, broken-down collagens and suspended fats redistribute throughout the pot. At Men-Eiji, this overnight rest is treated as seriously as the boil itself. Chefs cool the broth carefully, often in insulated vessels, allowing the temperature to drop gradually so the structure of the liquid remains intact and the surface stays protected.

In food science terms, resting allows the long chains of collagen released from pork and chicken bones to unwind further and bind more water, producing the silky mouthfeel that defines great tonkotsu. Amino acids such as glutamic acid, the same compound that gives seaweed and aged parmesan their pull, continue to dissolve into the liquid long after the pot has left the stove. The result is not a thicker soup alone, but a more nuanced one, with savoury notes that linger on the palate rather than disappearing the moment you swallow.

Australian chefs working with bone broth operate under Food Standards Australia New Zealand (FSANZ) guidelines for safe cooling of protein-rich liquids. The principle of cooling broth from 60°C to 21°C within two hours, and from 21°C to 5°C within a further four hours, mirrors the careful temperature management practised at Men-Eiji. Both food safety codes and ramen craft recognise that rushed cooling can degrade flavour and compromise texture, which is why the overnight model has spread from Sapporo into serious kitchens across Sydney and Melbourne.

Collagen, marrow and the architecture of umami

Bone broth builds flavour in layers, and each layer depends on time as much as temperature. Pork bones contribute collagen, marrow and a small amount of intramuscular fat. Seafood shells and frames, the "gyokai" half of gyokai-tonkotsu, add iodine-rich depth and a briny sweetness. When simmered together, the bones surrender their mineral content while the cartilage softens into gelatin. Men-Eiji's overnight rest gives that gelatin time to stabilise, and gives the minerals time to integrate rather than sit suspended in a raw, unfinished state.

The umami compounds released during this process include inosinates from pork, glutamates from kelp and shellfish, and guanylates from dried mushrooms and certain fish. Combined, these compounds create synergy, meaning the perceived savouriness is greater than the sum of its parts. This phenomenon, known as umami synergy, is the same principle behind the popularity of dashi in Japanese cuisine and the rising demand for slow-cooked bone broth in Australian wellness circles, where collagen-rich liquids have become a staple in Sydney and Melbourne café menus.

The fat content also matters. As broth cools overnight, emulsified fat rises and partially solidifies, trapping aromatic compounds within its lattice. When reheated the next morning and strained, the broth keeps those aromatics suspended rather than boiling them off into the steam. The flavour profile moves from sharp and aggressive to mellow and integrated, exactly the character Men-Eiji has built its reputation around.

Jun Furukawa's craft and the human element

Broth may follow chemistry, but the choices behind it remain deeply personal. Jun Furukawa has spent years refining the specific blend of pork bones, niboshi, katsuobushi and aromatic vegetables that defines the house style. He has taken this broth on the road through international pop-ups, including collaborations in cities such as Sydney, where Australian diners have had the chance to taste the overnight-developed base firsthand. His work has earned Men-Eiji a Michelin Bib Gourmand, an accolade awarded to restaurants offering exceptional food at good value.

The overnight rest at Men-Eiji is not a passive afterthought. Furukawa and his team test the broth the following morning, tasting for clarity, salinity and mouthfeel, then adjusting with tare before service. This quality check mirrors practices in some of Australia's most respected ramen kitchens, from Sydney's CBD to Brisbane's growing Fortitude Valley scene, where chefs routinely taste and tweak each batch before lunchtime service. Experience and patience, rather than machinery, set the standard.

For diners, the takeaway is that broth of this depth cannot be rushed. Even when Furukawa experiments with faster methods for pop-up events, he returns to the slow, overnight model at both Hiragishi BASE and Duck Ramen EIJI in Sapporo. The brand has resisted the temptation to industrialise its process, treating each day's batch as a fresh canvas and a chance to refine the house style.

Gyokai-tonkotsu and the Sapporo tradition

Sapporo's ramen history is inseparable from the gyokai-tonkotsu style that Men-Eiji has championed. While miso ramen is the city's signature, the seafood-and-pork-bone broth reflects Hokkaido's coastal and agricultural identity. Pork bones arrive from regional farms, while kelp and seafood often come from the same cold waters that supply sushi restaurants from Tokyo to Perth and Adelaide. The cold northern climate is part of the recipe.

The cold Hokkaido climate also helps the overnight rest. Winter temperatures in Sapporo regularly drop below minus five degrees Celsius, creating natural refrigeration and a slow, even cooling that supports the broth's transformation. Australian ramen makers face the opposite challenge. In Sydney or Melbourne, even winter nights rarely drop below five degrees, so insulated cooling and controlled refrigeration become essential to reproduce the same flavour profile. Men-Eiji's method has therefore travelled well precisely because it works within environmental constraints and translates to warmer kitchens with the right equipment.

Sapporo's dish culture embraces richness. Locals expect a broth that coats the spoon and a tare that pushes flavour forward without overwhelming the noodles. Furukawa's overnight method produces exactly this balance, and Australian fans of Japanese food have come to recognise the same hallmark in imported and locally made gyokai-tonkotsu bowls popping up in places like Melbourne's Hardware Lane and Brisbane's Fish Lane.

How Australian ramen lovers experience this depth

Australia's relationship with ramen has shifted over the past two decades. What began as a niche interest in Japanese cuisine has grown into a nationwide obsession, with shops opening from Hobart to Darwin. Melbourne alone is home to several dozen dedicated ramen-ya, while Sydney's competitive food scene rewards chefs who can deliver depth without heaviness. Brisbane's recent growth in Japanese dining has also created space for richer, broth-forward styles.

Diners Down Under often describe Men-Eiji's broth as "rounded" or "complete," words that capture the overnight rest effect more accurately than any technical term. Australian food media, including critics from The Sydney Morning Herald and The Age, have highlighted the brand's Michelin Bib Gourmand as a sign that Sapporo's ramen tradition deserves the same attention historically given to sushi and tempura. The cultural exchange between Hokkaido and Australia's coastal cities continues to deepen.

For Australians unable to travel to Hokkaido, pop-ups hosted by Jun Furukawa and his team have offered temporary windows into this overnight craft. These events often sell out quickly, with tickets released through Melbourne and Sydney event platforms. For those who have tasted the broth in person, the overnight question becomes less theoretical and more a matter of seeking out the same depth at home through careful technique and patience.

Comparing broth techniques used in modern ramen

Different chefs approach broth development in different ways, and the contrast helps explain why Men-Eiji's overnight method produces such distinctive results across key variables that influence flavour, body and clarity.

Technique	Active cooking time	Resting or aging	Flavour profile	Best suited to
Standard simmer (8–10 hours)	8–10 hours	Minimal	Clean, lighter	Shoyu and shio styles
Overnight rest at Men-Eiji	10–12 hours	8–12 hours	Deep, rounded, umami-rich	Gyokai-tonkotsu
Pressure-cooker method	2–3 hours	None	Intense, slightly metallic	High-volume shops
Continuous multi-day simmer	24–48 hours	None (continuous heat)	Thick, heavy	Specialty regional styles

The overnight rest sits in the middle of these approaches. It allows more flavour development than a quick simmer while avoiding the muddy, over-reduced character of multi-day cooking. For a brand like Men-Eiji, which values balance as much as depth, this middle path produces the most consistent expression of its house style.

If you want to explore broth development further or learn how to identify a well-crafted gyokai-tonkotsu, browse the menu and locations through brand resources and start planning your visit to Sapporo's Hiragishi and Susukino districts.