Monday 30 August 2010

Bread deserves a longer post

Those of you who know me know how much I love bread. Even if it’s not your favourite thing, you have to admit that it is rather fascinating how simple ingredients such as flour, water and yeast combine to give rise to a wonderfully textured and tasty food. The secret to a great loaf is in the yeast: the live, single-celled fungus (Saccharomyces cerevisiae) that makes bread dough rise. But how is it that those dried granules that come in the little paper packets you get at the supermarket come alive and make a mix of flour and water leaven? The best way to understand how flour + water + yeast = bread is to actually bake the stuff. I’m going to follow this very simple “No-Knead Bread” recipe. No kneading means you don’t have to spend two hours in the kitchen mixing, folding, pressing and stretching the dough. The yeast does all the hard work for you but it needs time – this recipe requires 14 to 20 hours for the bread to rise. Trust me, it’s worth the wait – and you’ll learn some exciting science along the way!  

So, let’s start with the ingredients (for 1½-pound loaf):

3 cups all-purpose or bread flour, more for dusting

¼ teaspoon instant yeast

1¼ teaspoons salt

Cornmeal or wheat bran [or more flour] as needed

And follow with effortless mixing:

1. In a large bowl combine flour, yeast and salt. Add 1 5/8 cups water, and stir until blended; dough will be shaggy and sticky. Cover bowl with plastic wrap. Let dough rest at least 12 hours, preferably about 18, at warm room temperature, about 70 degrees [ºF = 21 ºC].

In step 1 of bread making the dried yeast, which consists of dormant cells of Saccharomyces cerevisiae, is reactivated. The fungus awakens as it comes in contact with warm water. The slow process that follows is called fermentation. Once reactivated, the yeast starts converting the carbohydrates in the flour into the simple sugars it likes to feed on. This reaction releases carbon dioxide and alcohol into the bread mix. Most carbon dioxide gas does not disappear into the air: it gets trapped inside the dough because of the gluten in it, formed when water is mixed with two proteins in the flour, glutenin and gliadin. The long, slow rise also helps the gluten molecules become aligned in a way that gives the dough a strong, elastic texture. The gluten structure traps air bubbles inside it, which are filled with the carbon dioxide released by the yeast. The more gas is released, the more the air cells inflate making the dough rise.  

(If the mixture was less wet and the rising time faster, as in other bread-making processes, the dough would need to be kneaded to help the gluten molecules align and give it the right structure and elasticity.)

2. The dough is ready when its surface is dotted with bubbles. Lightly flour a work surface and place dough on it; sprinkle it with a little more flour and fold it over on itself once or twice. Cover loosely with plastic wrap and let rest about 15 minutes.

3. Using just enough flour to keep dough from sticking to work surface, or to your fingers, gently and quickly shape dough into a ball. Generously coat a cotton towel (not terry cloth) with flour, wheat bran or cornmeal; put dough seam side down on towel and dust with more flour, bran or cornmeal. Cover with another cotton towel and let rise for about 2 hours. When it is ready, dough will be more than double in size and will not readily spring back when poked with a finger.

When the dough is folded over and shaped into a ball, the air cells inside it are moved and get distributed more evenly. The yeast, now highly active, keeps releasing carbon dioxide making the dough rise much faster than before. At the end of steps 2 and 3, air cells are inflated and homogeneously distributed throughout the bread dough giving it the perfect consistency.

4. At least a half-hour before dough is ready, heat oven to 450 degrees. Put a 6- to 8-quart heavy covered pot (cast iron, enamel, Pyrex or ceramic) in oven as it heats. When dough is ready, carefully remove pot from oven. Slide your hand under towel and turn dough over into pot, seam side up; it may look like a mess, but that is O.K. Shake pan once or twice if dough is unevenly distributed; it will straighten out as it bakes. Cover with lid and bake 30 minutes, then remove lid and bake another 15 to 30 minutes, until loaf is beautifully browned. Cool on a rack.

Once the dough is in the oven, the heat will continue to make the mixture rise as more carbon dioxide is released and the air cells expand. The yeast is eventually killed as the temperature continues to increase. The mixture stops rising, the gluten hardens, and the dough becomes solid. The bread is ready! Enjoy!

The end result (topped with a tomato mix).

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