Baking with Baking Powder, Yeast, and Sourdough Starter
THE BASICS OF LEAVENING AGENTS
Baking Powder
Baking powder, a dry leavening agent added to flour-based cake, cookie, and quick bread mixtures, releases carbon dioxide in the mixture when wet, expanding the air pockets that already exist and causing the mixture to rise. In double-acting baking powders, the most commonly available type, a second heat-activated rise will happen once the dough or batter goes in the oven.
• Many bakers advise against buying baking powders with aluminum in them, as it can give a metallic taste to your baking. Rumford brand does not contain aluminum. Or you can follow baking specialist Shirley Corriher’s recipe for making a batch of homemade baking powder: Combine 1 tablespoon baking soda, 2 tablespoons cream of tartar, and 1-1/2 tablespoons cornstarch. Replace commercial baking powder 1:1 with this mixture.
• Use the exact amount of baking powder indicated in the recipe, as overleavening can cause too many carbon dioxide bubbles to form together, creating large bubbles that cause the baking batter to sink.
Yeast
Working with students at my cooking school over the past twenty years, I’ve found that the idea of working with yeast instills more fear than possibly any other ingredient. The first time they make a brioche from scratch, however, not only do they realize that their fears were completely unfounded, but they beam with pride when they pull their puffy, golden loaves out of the oven.
When flour comes into contact with water, two proteins—glutenin and gliadin—bond together to form another protein: gluten. Protein is what gives bread its structure, and kneading bread helps to further develop the gluten. Yeast’s main mission in life is to eat the sugars (in this case, the flour) in the dough, in the process releasing carbon dioxide, first as the dough rises and then later as it bakes. The gassy bubbles become trapped in the dough, helping the rise and creating the lacy structure we associate with bread.
Types of Yeast
There are several types of yeast, some of which can be used interchangeably. My go-to yeast for making brioche is traditional active dry yeast. I like the drama of proofing the tiny pellets in warm milk and watching them bubble up, and it gives my students confidence to see the chemical reactions at work. However, my tests show that instant yeast works just as well and can be added directly to the flour without the need to proof in liquid. Instant yeast is my go-to yeast for instant no-knead pizza dough; its quick and easy character seems to suit this dough best. But don’t let the various options put you off baking with yeast—just buy whatever yeast is most readily available near you.
• TRADITIONAL ACTIVE DRY YEAST: 100 percent yeast that comes in packets in small, dry pellet form. This yeast needs to be proofed in a warm liquid in order to activate it and so that it can be seamlessly incorporated into the dough.
• INSTANT YEAST: This kind is not always 100 percent yeast and may have some additives, such as the mysterious E491 and ascorbic acid. Instant yeast has smaller grains than active dry yeast and can be added directly to the flour in the mix. There is no need to proof instant yeast.
• FRESH YEAST: This is 100 percent yeast and comes in a claylike block. It can be crumbled and used like active dry yeast. This yeast needs to be proofed
Tips
• Be vigilant about the “use by” date. Old yeast may not work, which you might not discover until much later in the baking process, and what a waste of good ingredients that is!
• All sorts of factors can contribute to how quickly a dough will rise, including the temperature of the room, so let visual cues be at least as much a guide as any time given in a recipe.
• Yeast loves heat, so if your dough is failing to rise, place it in a warm place, such as next to a radiator, near a stove with a pilot light, or in a warming drawer.
Sourdough Starter
A starter is simply a dough made from flour and water, left out on the counter at room temperature to harvest the natural yeast in the air. With a little love and attention, in just a few days you will have a bubbling starter, alive with natural yeast, that will give your sourdough a flavor and texture impossible to achieve with commercially bought yeasts.
Creating, nurturing, and developing a starter or natural yeast to make your own bread is admittedly more complicated, challenging, and time-consuming than using commercial yeast, but the rewards and satisfaction are immeasurable. The process is not complicated, but it does require attention—and a little corner of your work top reserved for it.
I have been making homemade sourdough—one loaf at a time—for nearly forty years. I have baked in gas ovens, electric ovens, and my own wood-fired bread oven, all to great success (and, yes, occasional total failures, too—I simply call them sourdough bread pancakes). Always curious and eager to improve any cooking technique, I signed up for two separate bread-baking classes at the San Francisco Baking Institute. The first class on sourdough bread was amazing, but I did return home more confused than ever, and with trial and error created the sourdough recipe I use to this day (page). I also attended their wood oven class with friends and learned to create an entire parade of breads for the oven. The one major tip I took away was using an infrared thermometer (see page xxviii) to gauge the exact temperature of the oven; I now use this tool every day to check the oven temperature or even the temperature in the refrigerator or freezer.
I have learned—and also know from artisanal bakers—that the environment matters. In Provence, my bubbling starter has an extra boost of life during the grape harvest in September and October from the sheer amount of yeast in the air from the many local wineries.
Tips
• Use the least-processed flour you can find. Best choices include organic unbleached flours or those from King Arthur flour.
• The starter should always have a fresh, yeasty, faintly acidic aroma and be full of lively bubbles. If it discolors or develops a foul aroma, discard it and start over.
• Always shape the dough after mixing, and bake after only one rise. Most starters are not strong enough to undergo a second rise.