SCIENTISTS have their eureka moments. For rice winemakers, those epiphanies usually come the instant they open a vat.

Pan Xingxiang (潘兴祥), a master winemaker in the Zhejiang Province city of Shaoxing, doesn’t even have to taste to judge the quality of the local specialty yellow rice wine, or huangjiu (黄酒).

All he needs is to look at, smell and touch the fermenting rice in the vat. Now 61, he draws on more than 40 years of experience.

Shaoxing rice wine, the best-known variety of huangjiu, has a history dating back to the Spring and Autumn Period (770-476 BC). Once used as an offering at state rituals and banquets, it has evolved over the centuries into a popular daily beverage.

Pan’s talent for recognizing a good brew stems from a fortuitous experience years ago.

In the early 1980s, while working as an apprentice at Dongfeng Winery — the predecessor of Kuaijishan, one of the largest Shaoxing rice wine companies — he and his colleagues fermented a batch of wine and stored it away in the warehouse.

They finally remembered it and opened the batch a decade later. Eureka! The wine had taken on a clear, brightly amber hue, with an intoxicating aroma.

“The rich color, aroma and fine taste of the brew left a profound impression on me,” said Pan. “That’s why I believe that good rice wine must be aged before it’s sold.”

The alcohol content of yellow rice wine can vary from 10 to 20 percent.

Although many alcoholic drinks generally mellow with age, wineries were often pressed to sell their products as soon as possible and replenish working capital. They didn’t have the luxury of waiting for their wines to age.

A common practice that continues to this day is to add caramel coloring to freshly brewed rice wine to give it a darker, more attractive hue.

The color of huangjiu typically ranges between yellow, amber and brown, darkening as it ages. In contrast, naturally aged huangjiu, which deepens in color without the addition of caramel, commands a significantly higher price.

When Pan left his previous job to join Pagoda, a major huangjiu brand in Shaoxing in 2002, he had the opportunity to replicate his past eureka moment.

Around 2004, Takarashuzo, a Japanese liquor company, approached Pagoda with an offer to import premium Shaoxing wine into Japan.

Pan crafted a batch of the wine in 2005, using the finest ingredients and formula. The finished product, instead of immediately hitting the market, was left to age for 10 years.

“In 2015, when this wine was finally unveiled, it became an instant hit,” Pan recounted. “We had always known that our method would work, but when we opened the vat, we found it exceeded our expectations.”

According to Pan, who is now officially retired but remains as Pagoda’s advisor, this product boasts a remarkably complex flavor, featuring floral tones, hints of almond, dried fruit and honey, with a lingering note of chocolate.

This exquisite wine, which Pan named Ben, or “Origin,” carries a sticker price of over 600 yuan for a 500-milliliter bottle, significantly higher than many mid to low-end variants.

“This is a reward from heaven for Pagoda Winery, a recognition of our adherence to seasonal rhythms and our reverence for nature,” Pan said.

“The timing of heaven and the energy of the earth” (天有时,地有气) has become Pan’s catchphrase, integral to his brewing philosophy. Like many industry veterans, he begins every year’s winemaking session on the first day of winter, according to the Chinese lunar calendar, which normally falls on November 7 or 8.

Unlike bigger wineries such as Guyue Longshan and Kuaijishan, which use mechanized production lines, Pagoda adheres to traditional manual brewing, which runs from early November to the beginning of spring the next year.

Pan explained that winter is the optimal season for brewing Shaoxing wine since water sourced from Jianhu Lake, a key ingredient, is considered at its best at that time of year, marked by stable microbial activity. Jianhu Lake is a lush network of waterways that surround and crisscross Shaoxing.

The resulting wine, whether drunk with sliced ginger, Chinese dates or preserved plums, or just enjoyed warm on its own, is believed to be particularly nourishing for those with cold constitutions.

As the creator of numerous high-end huangjiu products and as an officially recognized “inheritor” of intangible cultural heritage in Zhejiang, Pan is widely revered within the industry as a master brewer.

However, he humbly rejects the label.

“The true master is the yeast,” Pan says. “It’s just that I can converse with the yeast. I know what it needs to work well, and I provide it. In return, it gives me what I want.”

Their pas de deux might be called “waltzing with yeast.”

A crucial step in the production of Shaoxing rice wine is called kaipa (开耙). This involves stirring the fermenting rice mash with a wooden rake at the right moment to facilitate heat dissipation and control the pace of fermentation.

Timing is pivotal. If the temperature is too high, the wine risks turning sour; if it’s too low, yeast activity wanes, leading to subpar flavors.

The quality of Shaoxing wine hinges on the skillful execution of kaipa — a set of procedures typically performed three to four times during the first 36 hours of fermentation.

In the past, the procedure relied heavily on an individual brewer’s experience, resulting in inconsistent quality due to variable temperature control.

Previously, winemakers had to endure the unpleasant routine of waking up three or four times every night to check on the fermenting liquid and stir it to dispel heat.

Few fellow brewers knew the science behind fermentation back then. Temperatures could fluctuate between 27-32 degrees Celsius, making the end-product highly unpredictable. Past experience was the only guide. Failures were sporadic, even among seasoned experts.

These challenges spurred creativity among the younger generations of winemakers. In 1985, Pan was sent to study microbiology for six months at Fudan University in Shanghai.

This experience proved life-changing. Leveraging his microbiological knowledge from Fudan, Pan reversed the traditional approach, lowering the initial fermentation temperature to precisely 24-25 degrees Celsius.

By using blowers, thermometers and relays, he not only solved the issue of uneven temperatures in the lead-up to kaipa, but also gained a better understanding of the best timing for human intervention.

This innovation reduced the need for random, frequent nocturnal checks, while also ensuring greater control over the wine quality.

After being pressed and pasteurized, the wine is then sealed in clay pots or vessels that are stacked up outdoors in neat rows, awaiting a period known as secondary fermentation.

Shaoxing wine stands out for its complex secondary fermentation procedures, ideally aided by colder weather, and better still, snowfall.

Prolonged, low-temperature fermentation metabolizes various flavor compounds in the liquid, resulting in a rich, smooth texture, clear color and intense aroma, Pan noted.

Over the past few years, he has tried to crystallize over four decades of winemaking experience into a guidebook, ensuring his legacy endures for future generations.

In an age dominated by industrial assembly lines and fast-paced consumer lifestyles, Pan believes that the centuries-old apprenticeship model, relying solely on the relationship of teacher and trainee, must evolve to keep up with the times.

To standardize and further elevate the brewing techniques of Shaoxing wine, he insists on a documented production process that is systematic and visual.

“In today’s industrial terminology, this would likely be called standard operating procedure, or modularized processes,” Pan said with a chuckle, betraying his familiarity with contemporary industrial parlance.

Despite his dedication to traditional methods, this veteran craftsman is not oblivious to the challenges facing his beloved industry.

The market for yellow rice wine is shrinking. The beverage had its glory days throughout the 20th century, even surpassing baijiu, the fiery distilled Chinese spirit, as the most popular drink across the country. At certain points, market penetration extended into northern China, where baijiu is a staple.

However, with the rise of other alcoholic beverages in the 2000s, particularly imported liquors like whiskey and vodka, consumers have a wider choice of products, and often the image of foreign drinks was considered chic.

As a result, the market share of yellow rice wine has been in a steep decline in recent decades. Today, consumption is largely limited to regions of production. Even renowned Shaoxing wine, once celebrated nationwide, now finds its customers primarily in the Yangtze River Delta region, and is under ever-greater threat of marginalization. Fewer young people drink it or love it.

Many share the stereotype — and misconception — that the wine is just for cooking, not for consumption on its own. This reality has prompted industry veterans like Pan to call for innovation.

However, contrary to the gimmick of creating trendy derivatives such as milk tea or coffee infused with yellow rice wine, he said he believes the industry needs another approach to wooing young consumers.

“Only things that are timeless can stay fashionable,” Pan remarked ruefully. “Sometimes, when talking about trendy things, we forget about the classics.”

Rather than focusing on peripheral products, the promotion of authentic rice wine requires more sophisticated approaches, Pan said, suggesting they might include introducing Shaoxing wine cocktails in bars and restaurants.

In effect, classic yellow rice wine is not alone in falling out of favor. Even deep-pocketed baijiu distillers are grappling with how to court the younger demographic, but at least they can still rely on their products’ traditional role in high-end gift-giving.

Instead of waiting for young people to come to Shaoxing wine, Pan advocates the industry to go to them.

“The idea that young people will spontaneously come to drink our wine as they age overlooks how fickle consumers are,” Pan argued.

Like-minded practitioners suggest that yellow rice wine brands need to rethink their marketing and pricing strategies. Many products currently compete in the price range of 10-30 yuan, leading to low margins, cutthroat competition and market saturation.

“The most dangerous competition is homogenization, which results in price wars,” Pan explained. “Thus, Pagoda Winery’s commitment to craftsmanship represents a differentiation strategy.”

Pagoda’s annual production maxes out at about 24,000 tons, with sales reaching 27,000 kiloliters and revenue totaling 600 million yuan. These figures are markedly lower than those of competitors such as Guyue Longshan and Kuaijishan.

However, Pagoda contributes 50 percent of the entire industry’s exports, which has slipped to about US$20 million a year from a peak of US$25 million.

Pagoda has set its sights on the premium end of the market.

“If the price is too low, it not only affects brand image but also sales volume,” Pan said.

Much as he hopes that young people will steadily learn to appreciate Shaoxing wine, Pan admits that efforts to promote the drink need to explore new avenues.

One solution lies in marrying yellow rive wine with the expanding influence of Chinese cuisine abroad. In this regard, Japan has lessons to offer its neighbor, he said.

“Just as Japanese sake is internationally renowned through the global embrace of Japanese cuisine, hopefully, Chinese cuisine’s global outreach can help to lift the profile of Shaoxing wine,” Pan said.

(The author, a former Shanghai Daily opinion writer, works as a business analyst and communication strategist. Xu Wen, Wang Shuangai and Wu Jinyi also contributed to this article.)