1. What Burnt Crusts on 15,000-Year-Old Pots Tell Us
In 2013 a team from the UK, the Netherlands, Sweden and Japan, led by the University of York, studied food residue on pottery from the Jōmon culture of Japan. The pots came from the end of the last Ice Age and were up to 15,000 years old, the oldest pottery that had been studied this way. Fats and chemical signals in the crusts pointed mostly to freshwater or sea animals.[1] It was described as the first study to directly ask why humans made pots.[1]
Two cautions. "Most" is not "all", and only pots that kept a crust could be tested. And the researchers did not claim to know why pots were invented. Dr Oliver Craig suggested that plentiful, reliable food along shorelines and riverbanks, during a time of severe climate change, may have made it worth the effort of making containers.[1] The idea that plentiful food made pot-making worthwhile is a hypothesis, not a settled fact.
It also shows that pots came from hunter-gatherers, not only from farmers.[1] So the story of cooking methods starts before farming. But why cook food at all?
2. Why Does Cooking Give the Body More Energy?
Harvard anthropologist Richard Wrangham argues that cooking changed human history because it lets the body get far more energy from food. In his figures, we may get about half the energy from raw starch, but much more once it is cooked.[2] Eating this way is easier, too, so it may have saved our ancestors time and effort.
When did cooking begin? Wrangham reads body clues such as gut size and rib cage and proposes about 1.9 million years ago, in Homo erectus. Many scientists put it at 200,000 to 300,000 years ago, a date Wrangham thinks is far too recent.[2] Firm evidence of fire exists only for a few hundred thousand years, so the experts still disagree. Note also that early cooks used fire directly. Clay pots are far younger, as section 1 showed.
3. Did Scarce Firewood Help Create the Wok?
The wok is a wide, rounded pan from China. Chef and writer Ken Hom, writing for the British Chinese Food Culture project, gives a timeline. Cast iron pots, the wok's ancestors, became common during the Han dynasty (206 BC to 220 AD). A wide pan called the kuo appeared in kitchens around 700 AD. Woks and steaming baskets became well known during the Song dynasty (960 to 1279).[3]
Hom links this to fuel. China's forests had been shrinking, and firewood and charcoal became very expensive, so cooks looked for ways to cook with as little fuel as possible. Food that cooks quickly in a little oil suited the wok, and its design allowed the new technique of stir-frying.[3]
This is a chef's account, not a laboratory study, and other sources give different dates. The fuel story is a plausible explanation, not a proven single cause. Scarce fuel probably helped explain the wok's spread, but it was likely not the whole reason.
4. How Can Steam and a Cone-Shaped Lid Save Water?
Fuel is only one limit. Water is another. Steaming cooks food in steam above the water, rather than sunk in it. A general reference notes that, compared with boiling, steaming can use less water, and may use less energy because less water needs heating.[4] The same reference says steaming equipment is very old, with stoneware steamers found in China's Yellow River valley reported to be thousands of years old. As this comes from a single encyclopedia entry, treat the dating as approximate.
The tagine is a North African clay pot with a cone-shaped lid. Steam rising from the stew hits the lid, turns back into liquid and drips down again, so the stew needs very little added water. Dish and lid are often linked to places where water is limited.[5] But the same source does not say the lid's shape was invented because of water shortage. That idea is a tidy explanation, not an established history.
5. How Can You Cook Without Any Pot at All?
The hāngi of the Māori people of New Zealand needs no pot. A pit is dug and a fire is burned on top of stones, usually for three or four hours, until they are extremely hot. The embers are removed, baskets of food are laid on the stones and covered with wet cloths, and the pit is filled with earth. After two to four hours the food is lifted out, cooked by the stored heat and the trapped steam.[6] The same source says that before metal arrived, food was wrapped in leaves or bark, and that large earth ovens were already used in the first Polynesian settlements in New Zealand.[6]
The source does not say why this method began, so we should not invent a reason. What we can say is how it works: heat from stones, and steam trapped under earth, can do the job of a pot.
6. So What Do Cooking Methods Really Tell Us?
Back to the starting question. Boiling, steaming, stir-frying and pit-cooking each work with a different mix of fuel, water, containers and food, and that is solid. Saying that each one was invented because of a particular shortage is a different, weaker claim. In our sources it was well supported only for the pottery crusts (what was cooked) and for how each method works. The "why" behind each method is mostly a hypothesis.
Try it yourself
Ask an adult to pour hot water into a mug and put a small saucer on top like a lid. Wait a minute, then lift it carefully with a cloth and look at the underside. Little water drops will have formed, just as in a tagine lid. Stand back from the steam. Do not touch the mug, saucer, or hot water; let an adult do the pouring and lifting.
At a museum, look at old pots for black marks on the base and sides, and read the label to see whether anyone has worked out what was cooked in them.