Saturday, October 05, 2019

Thoughts on Pollan's Cooked: Explains the science & history of the most commonplace of things - really learned a lot about fermentation

I read Michael Pollan's masterwork Cooked with great interest. This book takes a simple thing – food and how we prepare it – and delves deep into the underlying science and history of this subject.

The book first discusses using fire and water for cooking. It covers topics such as the Maillard reaction, which gives food flavor, and the way a stewpot acts as a second stomach, in a sense, predigesting foods and opening up their nutritional value.

I found the final section of the book, on fermentation, the most interesting. Fermentation ("cold fire") uses microorganisms to digest foods partially and to create flavors. The book highlights several key fermented foods – in particular, bread, wine, and cheese – and discusses various aspects of the fermentation process.

First, considering bread, fermentation allows us to readily use grasses for food and reclaim much more solar energy. The book suggests that ~90 percent of the energy in food is lost at each step of the food pyramid; thus, being able to eat grass directly is a major triumph of the agricultural revolution. Of course, nowadays, we have taken this fantastic process even further and essentially industrialized grass in the form of white bread -- taking out much of the original nutrients, including fiber, and then putting different nutrients back in. Another exciting aspect of baking bread is what Pollan describes as an emergent phenomenon. Most other forms of cooking, for instance, heating by fire or warming in a pot, involve a simple extrapolation of the preparation conditions. Baking bread is different. It is a "system property," where one combines various ingredients and makes something completely different than the original constituents. Pollan also describes how gluten acts almost like an elastic to create cavities in bread that can fill with gas and facilitate rising.

The next fermented food Pollan discusses is wine. To make it clear how easy it is to achieve fermentation, he shares humorous stories from his childhood of fermenting grape juice and having the vessel burst. He also brings up a philosophical question of whether we have domesticated Saccharomyces cerevisiae or whether it has domesticated us: alcohol itself, which is the product of many fermentations, is toxic to most organisms, yet we have evolved enzymes and pathways in our liver to break it down. Pollan also talks about how one can understand the different flavors of wine in terms of the various microorganisms available. Humans, in a sense, have co-evolved with wine and can benefit from having a glass a day based on a variety of health indicators.

The final section on fermentation talks about cheese. Cheese represents the product of rotting or decay in its extreme. Pollan describes cheese fermentation as a multistep process where, initially, microorganisms aerobically colonize the center of a bit of milk, digesting it partially and raising its pH, but eventually, the increasing acidity fouls the microbes' nest. Then, there is effectively an ecological succession where other species of bacteria replace the initial microbes; this continues to raise the pH. What I found most interesting is that a secondary fermentation then occurs from the outside of the cheese, where yeasts – which are aerobic – send in their hyphae and partially neutralize the increasing pH. The competition between these different fermentations gives rise to new chemistries, flavors, and compounds.

Cheese is also unusual in that it represents the nexus for competition between two current groups of people: the fermentos, those who believe in the importance of microorganisms for health and for giving food its flavors, and the Pasteurians, those who want to purge all foods of microbes. Their differences are evident when choosing a vessel for making cheese: should it be made out of old rotten, moldy wood or modern stainless steel?

The overall discussion of fermented foods points to the legacy of the agricultural revolution and the great importance of microbes in day-to-day life.

Altogether, I highly recommend this book. I find myself revisiting many of the book's points when I enjoy various meals and purchase things at the grocery store.

Cooked: A Natural History of Transformation – April 23, 2013
by Michael Pollan