Sunday, April 13, 2014

Bread Starter

Teaching is the best way to learn, and this term I have the great pleasure of teaching a class on the science of bread, which I hope will make me more knowledgeable not only about the theory but also the practice of bread making. This breakfast spread of fresh breads at a recent conference in Germany offered further inspiration for bread baking.

And so, along with my students, I have been tackling the challenge of cultivating and nurturing a bread starter, following the detailed instructions from Chad Robertson’s new book on whole grain baking, Tartine Book 3.

The process involves a certain degree of precision (flour and water doled out in grams) and a great deal of chance, as one hopes for wild yeast and lactic acid bacteria to alight in one’s bowl and set up shop fermenting the complex polysaccharides of the grains. 

Magically my flour paste started to produce bubbles after a day (can one fault the proponents of spontaneous generation?)

Rather than leave it all to chance, I took my starter out for a bit of wild yeast hunting at Noisette Pastry KitchenI can't be sure whether this inoculation helped along the starter, but over a matter of days, I had an actively bubbling culture with a somewhat pleasant yogurt smell. 

How is it it that time and again, when people offer up a flour paste to the air, they are able to produce a leavening for bread? What we consider as the generous efforts of yeast and lactic acid bacteria to aerate our bread and fill it with delicious flavors, is, from a microbial perspective, quite antisocial behavior. The yeast strains that humans have selected over our history for their utility in bread, wine, and beer making, are unusual among microbes in their metabolic choices. When confronted with an abundance of simple sugars and plenty of oxygen with which to burn this fuel through aerobic respiration, Saccharomyces cerevisiae instead chooses to gobble these up in the sloppy and wasteful process of fermentation. Their voracious devouring of resources, spewing fermentation products in the process, inhibits the growth of other microbes who are outcompeted and repulsed by the yeasts' greedy and sloppy eating habits. Only the like-minded lactic acid producing bacteria will set up shop with the yeast, using a similar wasteful fermentation strategy once oxygen is depleted from the environment. And thus bread starters, although possessing individual nuanced flavors, are remarkably similar in their composition of microbial boors, who can produce the most refined breads.

Stay tuned for experiments with baking with this starter. And you can read more about my co-teachers' adventures with starters here and here.


Raghu Parthasarathy said...

Hi Karen -- You should take a picture of your bread dough under a microscope -- maybe we (& your students) can spot your boorish yeast!

ediblethings said...

I found out about this fascinating course via Culinaria Eugenius. I have decided to join in, a little late, and on facebook, until I get confidence enough to start making original content that I can blog about. Thanks to all of you blogging course leaders for getting me to finally take the sourdough plunge!