By Jane Sonnenschein · July 3, 2026

Until last night, I did not know that butter was not fat from a cow’s body.

Written out like this, someone may already be laughing. But after thinking about it, I still feel that this small thing is worth writing about. Because the truly interesting question is not whether I knew where butter came from. It is why one person would think, “How could you not know this?” while another person would naturally assume that butter, or huangyou¹ in Chinese, was simply some kind of fat from a cow.

The story began very simply. My daughter’s school is about to start the summer holiday, and on the last day there is a tradition: parents can prepare a little breakfast from different countries for the children to share at school. The note from school specifically reminded us that because the weather was hot, it was better not to bring dairy products or egg products, since they spoil easily.

I was not very eager to prepare something. If you want to make a proper Chinese breakfast, it is actually quite a lot of work. Doujiang, baozi, huntun, zhou, youtiao² — none of these are things you can casually take out of the refrigerator and bring to school. That day, we happened to still have a cheesecake at home that my husband had made two days earlier, so I casually said, “Why not let her bring the cheesecake?”

My husband laughed when he heard this. He asked me, “Do you know what cheesecake is made of?”

Of course I knew there were biscuit crumbs, cream, and fruit sauce in it. But he said, “Didn’t the note say not to bring dairy products? Butter, cream, cream cheese — aren’t they all dairy products?”

Then we had a conversation that I still find funny.

I asked, “Butter is made from milk too?”

He looked completely shocked, as if he had just heard me ask whether the sky was blue. He said, “You don’t know that butter is made from milk? Isn’t that something even primary school children know?”

I was also shocked. I said, “I always thought huangyou was oil from a cow’s body.”

In my understanding, this reasoning was not absurd at all. Chinese people are very familiar with zhuyou³. What is zhuyou? It is oil rendered from the fatty meat of a pig. When I was a child, many families knew that cooking with zhuyou made food fragrant, that rice mixed with zhuyou tasted good, and that zhuyouzha was even more delicious. Even if someone no longer eats zhuyou today, the word is still very easy to understand: zhuyou means oil from a pig. So what about huangyou? Its Chinese name contains no character for “milk,” no character for “dairy,” and nothing in the word suggests that it comes from milk. It is called “yellow oil,” and it often appears together with Western food, steak, and bread. If I understood it as some kind of oil from a cow, wasn’t that actually quite natural?

But in my husband’s world, this was completely unbelievable.

He grew up in an environment where dairy products were very common. Milk, butter, cheese, yogurt, and cream were not isolated foods to him, but an entire set of lived experience. School teaches it, supermarkets are full of it, it appears on the breakfast table every day, and baking depends on it. So when he hears the word “butter,” his mind naturally connects it with milk and cream. When I hear the Chinese word huangyou, my mind naturally connects it with zhuyou, beef fat, and animal fat.

Neither of us was thinking randomly.

We were simply starting from the worlds we knew best.

What made it even funnier was that he did not give up. He deliberately searched on Google for how Chinese people understand huangyou. The explanation Google gave actually included something close to “yellow oil.” In other words, the two Chinese characters huangyou really can easily lead a person who has not grown up with much dairy experience toward the idea of “yellow oil,” rather than “fat processed from milk.”

Later, I sent this question to a small group chat and asked two Chinese friends who have also lived in Germany for more than twenty years, “Do you know what butter is made from?”

One friend answered, “Milk?” with a question mark after it. The other friend understood it almost exactly the same way I did and thought huangyou should be similar to beef fat, just as zhuyou is oil from a pig’s body. Then the first friend actually agreed and began to doubt her own answer.

At that point, my husband was even more speechless. He probably felt that three people who had lived in Germany for more than twenty years were still unclear about where butter came from. To him, it was simply unbelievable.

But I do not think this proves that we are ignorant.

Before I left China, I had barely eaten butter. When I was a child, even drinking milk was not like today, when you can casually pick up a carton of long-life milk or fresh milk from a supermarket shelf. Back then, milk had to be ordered. A bottle was delivered to the home every day, and then we had to bring it inside and boil it. In the food world of my childhood, the things that appeared frequently were doujiang, youtiao, plain zhou, rice, huntun, baozi, rice noodles, zhuyou, rapeseed oil, and peanut oil — not butter, cheese, and cream.

So if a person does not know that butter is made from milk, it does not mean she has no common sense. It only means that her common sense did not grow out of butter, cheese, and baking.

Common sense never falls from the sky. Common sense grows out of a person’s kitchen, dining table, market, school education, supermarket shelves, and the names given by language.

A German person may know very early that butter comes from milk, but he may not understand why rice mixed with zhuyou tastes so fragrant. He may not know why Chinese people used to deliberately buy fatty pork to render oil. If you tell him about zhuyouzha, he may only think it is some strange kind of fat. But in the taste memories of many Chinese people, it was a small luxury in poor times, the secret that could suddenly make a bowl of rice delicious.

In the same way, a European or American person may feel that Pokémon, certain game characters, or certain symbols of popular culture are basic knowledge that everyone in the world should know. But if a person does not play games, does not watch Japanese anime, and does not live inside that cultural circle, what is so strange about not knowing that the Chinese name is Baokemeng?

The world does not have only one knowledge map.

The gaming world has its common sense. The kitchen has its common sense. Villages have village common sense. Cities have city common sense. China has Chinese common sense. Europe has European common sense.

What makes me uncomfortable has never been that other people know things I do not know.

I am willing to learn, and I am willing to admit what I do not know. What makes me uncomfortable is that some people take the default settings of their own culture and treat them as basic answers that the whole world must know. Once you do not know them, they say in an astonished tone, “You don’t even know this?”

Hidden behind that sentence is sometimes a very subtle kind of arrogance.

It may not be intentional. Many people do not mean to look down on you. They have simply stood since childhood in a relatively powerful cultural position, and they are too used to treating their own life experience as the world standard. For a long time, Western culture was indeed a dominant culture. Films, music, games, brands, education systems, and food systems were exported around the world. As a result, many Western people can easily develop an unconscious feeling: what we know is mainstream; what we grew up with is basic; if you do not know the common sense of our world, then you seem not very worldly.

But why should that be?

The Chinese world is also vast. Our language, food, festivals, history, mythology, markets, kinship relations, cooking methods, Chinese character-based naming, and online ecosystem also form an extremely complex system of life.

A Chinese child may know very early that doujiang is made by grinding soybeans, that youtiao must be deep-fried, that zhuyouzha is fragrant, that people eat zongzi during Duanwu Jie⁴, that Sun Wukong caused havoc in Heaven, that Nezha and Ao Bing are part of a shared mythological imagination⁵, that people paste chunlian during the Spring Festival⁶, and that the word shanghuo carries a whole system of bodily experience behind it⁷. But many Western people may not understand these things either.

When they do not know, we can explain.

So why should we be mocked when we do not know something from their world?

There is not only one kind of “basic” in the world.

A person’s “basic” is simply the set of life experiences that they were repeatedly fed, repeatedly confirmed, and repeatedly used while growing up. Change the language, change the dining table, change the childhood, change the supermarket shelf, and so-called common sense changes too.

So what that small matter of butter truly reminded me was not that I had filled in another missing piece of knowledge. It reminded me once again of this: one of the easiest mistakes people make is to stand inside their own world and laugh at others for not standing in the same place.

True worldliness is not about knowing how much of other people’s common sense you possess. It is about knowing that your own common sense is not naturally above someone else’s.

If a person is truly broad-minded enough, they will not rush to laugh at someone for not knowing that butter is made from milk. They will not assume someone is backward simply because she does not know a certain game character or a certain pop culture symbol. They will first think: Why does she not know? Did this thing have a place in her lived experience? How does her language name it? What appeared on her childhood dining table, and what was absent from it?

To respect a person is not only to respect what she knows.

It is also to respect why she does not know.

Many conflicts in cross-cultural relationships do not happen because two people are truly so far apart. They happen because one person is too used to treating his or her own world as the default answer. Whether in marriage, friendship, or immigrant life, what we most need to practice is precisely this: to admit that the world has more than one explanation, that common sense has boundaries, and that what another person does not know is not necessarily ignorance. It may simply mean that she comes from another world.

So in the end, that piece of butter did not go to school yesterday evening.

But it did give me an essay.

I think I will probably remember this incident for a long time: I once seriously believed that huangyou was oil from a cow’s body. Now I know that it is not.

But what I want to remember even more is something else:

Do not lightly laugh at what another person does not know.

Because what you think is common sense may only be the default setting of your own world.

Notes on Chinese Context

¹ Huangyou（黄油）literally means “yellow oil” in Chinese. In modern Chinese, it means butter. But the word itself does not contain the character for milk or dairy. For someone who did not grow up with butter, cheese, cream, and baking as everyday foods, the word can easily sound like a type of animal fat rather than a dairy product.

² Doujiang（豆浆）, baozi（包子）, huntun（馄饨）, zhou（粥）, and youtiao（油条）are common Chinese breakfast foods. Doujiang is soy milk made from soybeans; baozi are steamed buns, usually with filling; huntun are wontons; zhou is rice porridge or congee; youtiao are deep-fried dough sticks often eaten with soy milk or porridge. Together they represent a very different breakfast world from bread, butter, cheese, and cream.

³ Zhuyou（猪油）means lard, oil rendered from pork fat. Zhuyouzha（猪油渣）refers to the crispy pieces left after pork fat has been rendered. In many Chinese families, especially in earlier and poorer times, zhuyou and zhuyouzha carried strong taste memories. They were not merely “fat,” but a source of fragrance, warmth, and a small sense of abundance in ordinary food.

⁴ Duanwu Jie（端午节）is the Dragon Boat Festival, a traditional Chinese festival. Zongzi（粽子）are sticky rice dumplings wrapped in leaves, usually eaten during this festival. They can be sweet or savory, depending on the region.

⁵ Sun Wukong（孙悟空）is the Monkey King from the classic Chinese novel Journey to the West. “Causing havoc in Heaven” refers to one of his most famous stories. Nezha（哪吒）and Ao Bing（敖丙）are figures from Chinese mythology and popular retellings; they are widely known in Chinese-speaking culture, especially through stories, animation, films, and children’s books.

⁶ Chunlian（春联）are Spring Festival couplets. They are pairs of red paper strips with auspicious phrases written on them, pasted on doors during Chinese New Year. They are part of the visual and cultural atmosphere of the Spring Festival.

⁷ Shanghuo（上火）is a Chinese concept of bodily imbalance often used in everyday life. It can refer to symptoms such as mouth ulcers, sore throat, acne, irritability, or a feeling of internal heat. It does not map neatly onto a single Western medical term. For many Chinese people, it is part of a practical everyday language for understanding the body, food, weather, and discomfort.

This essay is also available in other languages:

Chinese version: 你以为的常识，只是你世界里的默认设置

German version: Was du für Allgemeinwissen hältst, ist nur die Standardeinstellung deiner eigenen Welt