Cooking. What’s Involved and What That Means

I continue with the exploration of cooking as all the operations humans use to turn raw materials into something edible, digestible, and nutritious (while realizing some of my readers may want to hold out for cooking as heating).

As several comments on my last post made clear, the words translated into English as “cooking” have different meanings in different languages.  This should mean that in analyzing how we prepare food, we should not be limited by contemporary English-language definitions of cooking.

And, to repeat, in any area of inquiry, progress is made by analyzing terms from “democracy” or “empire” to “mind” or “salt” or “heat” as a way of broadening and deepening understanding.

What’s Involved

I find it useful to think about cooking as involving four kinds of operations (use of changes in temperature, use of mechanical force, use of chemicals, and use of microorganisms) PLUS the mixing or combining of materials. This is not original to me.

The categories overlap. The use of heat, for example, produces chemical changes, while the use of microorganisms produces heat.  The categories are usually used in sequence or iterated several times.  Cut, then grill meat. Bake, then mash roots such as taro or yam. Even so, it’s useful to separate them conceptually.

1.  Changing Temperature (Thermal Changes)

To begin with the archetypal (or stereotypical) sense of cooking, meat grilling over an open fire.  Actually, though, like frying, this is a very pricey and tricky way to use heat, so boiling, steaming, baking, roasting have been commoner through most of history.


Drying in the sun and wind preserved ingredients and often changed their character, as in the case of jerky, stockfish, and apricots.  Evaporating was essential to boil down sugary liquids to sweeteners.

Hanging pasta to dry

Drying pasta in twentieth century Italy

Freezing adds different textures. We may think of the ice cream family but as Zona Spray has shown, Eskimos (her word) have long been using freezing to create sophisticated culinary sensations.

2. Using Physical Force (Mechanical Changes)

Cutting, grinding, pounding, pressing, shredding, grating, churning and other processes reduce big awkward carcasses to manageable portions, tough little cereal grains to flour or granules that cook up to a nice texture, get oil out of seeds, and turn milk into butter. I usually emphasis grinding but I just love this little image of a man using his entire force to depress the pestle to husk rice.

Foot operated pestle

Pounding the husks off rice or other grains, Japan

And the churning of milk for butter was so time-consuming in the late nineteenth century that even dogs were corralled into running on treadmills to get the job done.

Churning butter

Churning butter

3.  Using Chemicals (Mainly Changing Acidity or Alkalinity)

Chemicals may sound awful but they have been used from way back.  Strong alkalis, in particular, have been used around the world, perhaps from naturally occurring salts in dry regions, perhaps from heating limestone or taking wood ashes and adding water (largely calcium hydroxide).  To alkalis, we owe  thousand year eggs, hominy and maize tortillas, skinned peaches, and shiny baked goods whether bagels or Chinese buns.

Use of sodium hydroxide in food processing

Dried cod prepared with lye (sodium hydroxide) to make lutefisk

Acids, often from fruit juices or bile, have been used to change the texture of fish, to flavor in marinades and for preserving and pickling.  Acids and enzymes from calves’ stomachs or a variety of plants curdle milk in preparation for cheese making.

Cheese making

Cutting milk with rennet to make cheese. Flickr


4.  Using Microrganisms (Biochemical Processes or Fermentation)

And then there are microorganisms.  I just love this picture of the fungus koji “flowering” on a substrate of cooked rice, the first stage in the preparation of a whole series of fermented foods.

Japanese koji ferments

Koji (Aspergillus oryzae) growing on rice.

Bread, beer, and rice wine; preserved sausages; hard cheeses, kenkey, an African maize products; Asian bean condiments.  Without the use of microorganisms our food would be less tasty, less safe, and less varied.

5. Mixing and combining

For reasons of taste, texture, health, and convenience, humans mix and combined different ingredients when they cook.  A seasoning of salt makes things taste better, fat and flour combined make interesting pastry textures, a bowl of soup with varied ingredients mades a balanced meal, meat and vegetables wrapped in a dough as a pie or sandwich makes a portable meal.

So all these processes, I include under cooking.

What That Means

1.  Cooking, all that cutting and grinding, heating, treating with chemicals, and fermenting makes the raw materials of food smaller and softer so that we don’t have to use as much energy clawing and chewing and digesting.  It’s not something we usually think much about but chewing and digestion take up a huge amount of an animal’s time.  As Richard Wrangham points out, chewing occupies chimpanzees six hours a day.

The effects of cooking on human evolution is a hot topic of research in anthropology right now. What is clear it that it gives humans more energy to do other things, quite likely including growing bigger brains.

2.  On the other hand, cooking requires energy.   As Naomi Duguid nicely summed it up for me the other day all cooking involves transfer of energy as raw materials are turned into food.

3.  So the interesting questions are the ones of tradeoff.

How much energy goes into cooking compared to energy saved?

Or, who exerts the energy for cooking and who benefits?  Who does the grinding and gathers the firewood?  And who has the energy saved for doing other things?  We all know that following the transition to farming, a high proportion of the people had to work the land so that a few could rule, pray, and fight.  We also need to ask what proportion of people (and which people) had to cook?  A huge number over much of history, I believe.

How does the energy that goes into cooking compare from style of cooking to another? Does it take more energy to cook maize rather than wheat or either of these rather than taro or yams? These differences could have had a significant impact on the differential development of societies.

How does the energy that goes into cooking affect the environment. The search for cooking fuel helped decimate woodlands in the past and the search for biomass for cooking remains significant today.

How does the energy required for cooking limit the energy used for other purposes?  We think fuel, but what about the water power needed to run grist mills to grind grain? How did this limit the use of rivers for navigation and for irrigation. Choices had to be made. How did it limit the use of water power in the metallurgical industries and in the textile industries?

Sad to say, we have very little information about the energy required for cooking in the past.  I have tried to get figures on the calories expended right up to the present by Mexican women in grinding maize, but no luck.  It was for centuries, and in parts of the country still is, significant.

In short, what’s involved in cooking  is the expenditure of a great deal of energy. And what that means is that give cooking its full due as a factor in human history, questions about where the energy came from, about differences in energy expenditure by men and women, rich and poor, wheat eaters and taro eaters have to be asked. Lots to get cracking on.



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2 thoughts on “Cooking. What’s Involved and What That Means

  1. David Hillel

    Hi Rachel,

    Thanks for another great post.

    I believe cooking may be extended even further. How about simply washing fruits and vegetable under running water (without detergent of course)? For many this simple act of washing an apple or a carrot is by itself cooking, as it renders these “non-foodstuffs unless washed” edible. Moreover, people may relate to raw meat as uncooked ingredient, but tend to forget that non-meat (or, grass) is actually being “cooked” for us (at least partinally, into proteins, but this can still be argued to be part of cooking) to become “raw meat.” This type of cooking is done by ruminants which WE domesticated for that actual (cooking!) purpose.

    So where does “the raw” end and “the cooked” start?


    1. Rachel Laudan Post author

      Thanks for the comment, David. Yes, I would include the use of water to wash. With all the pre-cleaned produce in modern supermarkets, it’s easy to forget that the “scullery” was once a place for this preliminary cleaning. Washing bits of insects out of the lettuce and bits of earth clinging to the root vegetables was a time-consuming chore without which the lettuce was unappetizing and the root vegetable inedible. Water was also important for leaching toxins from, say, acorns.

      Yes, animals do part of the pre-digesting for us. This was recognized from very early on. In traditional Hindu thought, for example, what we would call “raw” milk was regarded as cooked in the body of the cow.

      So I agree the boundary between the raw and the cooked is not as sharp as it might appear. I do think, however, that a key distinction between humans and non-humans is that most human calories come from foods that have been radically transformed from their raw materials by not just one but a whole series of operations.

      Chocolate, for example! And your chocolate looks wonderful.


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