In the northwestern Chinese city of Lanzhou, where the Yellow River cuts through the landscape and the air carries the scent of hand-pulled noodles, there is a humble snack that has been cooling and comforting locals for over a thousand years. Its name is tianpei zi (甜醅子) – sometimes written as tianpei (甜胚) or called jiupei zi (酒醅子). Often described as the “natural ice cream” of Lanzhou, this sweet, fermented grain snack is more than just a treat – it’s a taste of history, a ritual of the seasons, and a symbol of home for generations of Gansu people.
What Is Tianpei Zi?
At first glance, tianpei zi resembles the fermented rice desserts found in southern China. But this is no ordinary jiuniang (sweet fermented rice). While the two share a similar fermentation process, tianpei zi is made not from sticky rice, but from naked oats (莜麦, youmai, also called yumai in the Lanzhou dialect), highland barley (青稞), or wheat. These hardy grains – staples of the arid, high-altitude lands of northwest China – give tianpei zi a chewy, satisfying texture that sets it apart from its southern cousin. As one local observer put it, the taste is “more rich, more pure, more fragrant” – a reflection of the bold character of the northwest.
The finished product is a bowl of plump, translucent grains floating in a milky, sweet-tart liquid with a gentle, aromatic hint of wine. The grains are soft yet chewy, each one bursting with the flavour of grain and fermentation. It is sweet without being cloying, tangy without being sour, and lightly alcoholic without being intoxicating.
A Taste of Tang Dynasty History
The story of tianpei zi stretches back over a thousand years. Historical records show that the technique for making this fermented grain snack was already popular during the Tang dynasty (618–907 AD) . In fact, the great poet Du Fu (杜甫) is said to have referenced it in his poem “Guest Arrives”, writing of “old fermented grains” (jiu pei) served to visitors.
For centuries, tianpei zi has been a fixture of festive occasions in northwest China. In Lanzhou, where rice and bamboo leaves were historically scarce, it became the de facto food of the Dragon Boat Festival (Duanwu), taking the place of the rice dumplings (zongzi) enjoyed elsewhere in China. From the Qingming Festival (Tomb-Sweeping Day) onwards, households would begin preparing tianpei zi, and by the time the Dragon Boat Festival arrived, the sweet aroma of fermentation would fill homes across the city. Neighbours would exchange bowls of their homemade tianpei zi, a gesture of goodwill and community.
The Art of Making Tianpei Zi
The process of making tianpei zi is a labour of love – a traditional craft passed down through families. It involves five essential steps: selecting the grain, washing, steaming or boiling, mixing with starter culture, and fermenting.
First, the grains – preferably plump, high-quality naked oats or highland barley – are carefully cleaned and dehulled. Traditionally, the grains are placed in a sack and beaten to remove the outer husk, revealing the tender white kernels within. The grains are then cooked – either boiled until they “bloom” open or steamed – until they reach exactly the right tenderness.
After cooking, the grains are cooled to about 35°C. A starter culture (jiuqu), similar to the one used for making rice wine, is sprinkled over the grains and mixed in thoroughly. The mixture is then placed in a ceramic pot or basin, covered, and wrapped in a thick quilt to keep it warm. It is left to ferment in a warm spot – traditionally on a heated kang (a traditional Chinese sleeping platform) or near the stove – for two to five days.
The key to success lies in temperature control. Too hot, and the fermentation goes awry; too cool, and the grains won’t develop that characteristic sweet-tangy flavour. This is where the maker’s experience comes into play – a skill honed over years of practice. When the lid is finally lifted, the grains have transformed: each kernel is now wrapped in a milky white “robe”, and the air is filled with the intoxicating fragrance of grain and wine.
How to Enjoy It
Tianpei zi is a snack for all seasons, but it truly shines in the heat of summer. The most traditional way to enjoy it is to scoop a few spoonfuls of the fermented grains into a bowl, add a generous splash of cold boiled water and a sprinkle of sugar, and stir. The result is a refreshing, sweet-tart drink with a subtle kick – the perfect antidote to the scorching northwest sun. As locals say, in summer it “clears the mind and refreshes the spirit”; in winter, warmed with hot water, it “warms the body and stomach”.
There is even a charming local saying: “Tianpei is sweet, and even the old and young can’t help but swallow their saliva. One or two bowls whet the appetite; three or four bowls fill you up like a meal.”
A Modern Revival
In recent years, tianpei zi has undergone a remarkable transformation. No longer confined to home kitchens and street stalls, it has become a symbol of Lanzhou’s food culture and a canvas for culinary innovation. The snack has been paired with beef noodles – “niu da” (big beef) – in a classic combination that has become a staple in many Lanzhou noodle shops.
More excitingly, tianpei zi has entered the world of new-style tea drinks. In 2011, the Lanzhou-based tea brand “Fang Ha” (放哈) – whose name means “put your worries aside” in the local dialect – pioneered the “tianpei zi milk tea” , blending the traditional fermented grains with milk tea to create a drink that has become wildly popular. The brand now sells over 5.3 million cups of tianpei zi milk tea annually. Other innovations include tianpei zi smoothies, tianpei zi yogurt, and tianpei zi green tea. The snack has even been industrialized, with dedicated factories producing tianpei zi at scale while preserving the traditional fermentation process.
A Bowl of Memory
For the people of Gansu – and especially for the countless Lanzhou natives who have left their hometown – tianpei zi is more than just a snack. It is a taste of home”. As one writer put it: “For the wanderer far from home, tianpei is the flavour code of their homeland. Whenever they think of that bowl of tianpei, still carrying the warmth of their mother’s hands, memories come flooding back like the tide”.
From the Tang dynasty to the tea shops of today, from the warm kang of a farmhouse to the bustling streets of Lanzhou, tianpei zi has endured – a sweet, fermented thread connecting past and present, home and away.
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