Bread, "the staff of life." I was amazed at the historical influence that bread has had on language and culture. If one was to study the history of bread more in-depth, one would truly find the history of the world. While this blog has been about ingredients and mechanics of bread making, I could not help turn my thoughts towards the more philosophical questions of bread.
One often hears people comment on the change of pace in modern life. Often times the reference suggests the underlying speed and ease with which we get things. Our physical needs are met with just one trip to the grocery store. We exchange dollars for fruits, vegetables, bread, even sweets. No more preparing, planting, sorting, waiting, baking, etc. It's funny how the thing that we miss, the thing that the "good'ol days" were full of, is work. Yet, we feel more overworked than ever. No time to tend a garden, or make bread at home. Honestly, few days seem to have enough time to make a 30-minute meal. The loss of our time to me, seems to be the loss of appreciation for the things that make us happy. Bread is a prime example.
Consider the time it took to make a loaf of bread 300 years ago. The wheat had to be planted, harvested, milled, turned into flour. The water had to be carried. Other ingredients were worked for, traded, who knows. At last, the lady of the house set out to make bread. The dough was made. It sat. A day or two later, the fire was lit, the oven preheated for hours before. The ashes cleaned, the fire adjusted. The dough was kneaded, formed, and set to bake. For how long, I don't know. Finally a loaf came out. The deliciousness of the bread was secondary, I think, to the substenance it provided. I don't doubt it was delicious. But it was appreciated as the reward of long and hard labor.
Manufacturers today produce dough with good aeriation and gluten structure in 4 minutes. Making bread today still takes time, but the time is not spent by the consumer. The question I am left to ponder then is, am I capable of appreciating a loaf of bread the way our ancestors were? In terms of flavor, our society accepts mass-produced bread with no qualms. It is good enough. Artisan bread tastes better, but is the difference enough? Based on the market, most people don't see a good enough difference to pay $4.50 for an artisan loaf versus $1.20 for Wonder bread.
So where does happiness come in? It is my personal philosophy that we can only appreciate the things that we know, and happiness stems from that knowledge. It is not up to me to say whether today's society is any more or less happy than our bread-making ancestors, but I know for a fact that I can't appreciate bread in the way they did. Maybe instant gratification isn't happiness at all. Maybe happiness is solely connected to the intangibles of time, effort, and labor.
Showing posts with label Lesson5. Show all posts
Showing posts with label Lesson5. Show all posts
Tuesday, April 3, 2012
Challah (Braided) Bread recipe
As posted by Dr. Patti Christie on http://ocw.mit.edu/courses/special-programs/sp-287-kitchen-chemistry-spring-2009/readings/MITSP_287s09_read05_Challah.pdf
Adapted from the Guggenheim Family, Zurich, Switzerland.
Ingredients:
Adapted from the Guggenheim Family, Zurich, Switzerland.
Ingredients:
- 1 package of dehydrated yeast (2 1/4 tsp).
- 1/2 cup sugar
- 2 cups of water at 115 - 120 degrees F.
- enough flour to make a dough (about 5-6 cups)
- 1 tbsp salt
- 2 tbsp oil
- 1 egg
- cooking spray
- egg yolk
- Mix together water and sugar. Make sure the temperature of the solution is between 110-115 degrees F.
- Sprinkle a package of yeast over the top and let sit for 10 minutes.
- Mix together egg, oil, and salt. Add to yeast mixture.
- Mix in the flour. The total amount of flour will be between 5-6 cups. Add 2 cups of flour and mix. Then add another 2 cups and mix well. Gradually add the rest of the flour to make a dough that is able to come off the sides of the bowl.
- Knead together until the dough is shiny and elastic.
- Spray cooking spray on bowl. Place dough into bowl and flip until covered with cooking spray.
- Cover with a piece of plastic wrap, which has been sprayed with cooking spray and also a towel. Let rise in a warm place (works best if the temperature of the dough is between 85-95 degrees F) until double in bulk. This will take about an hour.
- Carefully punch down and divide the dough into pieces to be braided.
- Braid the bread and cover with the plastic wrap and towel to let rise for about 30 minutes (half the amount of time as the first rising).
- Mix equal parts of egg yolk and water. Brush egg yolk mixture on top of dough.
- Cook at 350 degrees F for 35-45 minutes or until it sounds hollow when tapped.
Staling
Though staling seems to involve the loss of moisture as the bread becomes dry, hard, and crumbly, it is more of an effect of starch retrogradation than net water loss. In 1852, Frenchman Jean Baptiste Boussingault conducted an experiment where bread was hermetically sealed to prevent moisture loss, yet it still became stale. Staling is now understood to be a manifestation of recrystallization and water migration out of the starch granules into the surrounding gluten network. The retrogradation of simple amylsoe molecules leads to the hardening of the bread. Branched amylopectins also retrograde, but do so more slowly. Certain emulsifying agents have been found to retard staling substantially. Manufacturers have added these to mass-produced bread dough for the last 50 years. True buttermilk and eggs have the same effects.
As long as the loaf is not too old, or has been refrigerated, staling can be reversed by reheating the bread above the gelation temperature of starch, 140 degrees F/60 degrees C. Toasting makes the interior of bread soft. A loaf of bread can be refreshed by heating in the oven.
Refrigerating bread can speed up the staling process by as much as 6 days! If bread is to be used in a couple of days, it is best to store at room temperature in a bread box or paper bag to reduce moisture loss. If bread is to be kept longer, it is best to wrap it in plastic or foil, and freeze it. Refrigerate bread only if it is to be toasted or reheated before consumption.
Bread tends to dry out before becoming spoiled. Still, bread that is kept at room temperature in a plastic bag allows moiture from the staling starch granules to collect on bread surfaces. The most commonly found toxic molds in spoiled bread are Aspergillus, Penicillium, Mucor, and Monilia sitophila.
As long as the loaf is not too old, or has been refrigerated, staling can be reversed by reheating the bread above the gelation temperature of starch, 140 degrees F/60 degrees C. Toasting makes the interior of bread soft. A loaf of bread can be refreshed by heating in the oven.
Refrigerating bread can speed up the staling process by as much as 6 days! If bread is to be used in a couple of days, it is best to store at room temperature in a bread box or paper bag to reduce moisture loss. If bread is to be kept longer, it is best to wrap it in plastic or foil, and freeze it. Refrigerate bread only if it is to be toasted or reheated before consumption.
Bread tends to dry out before becoming spoiled. Still, bread that is kept at room temperature in a plastic bag allows moiture from the staling starch granules to collect on bread surfaces. The most commonly found toxic molds in spoiled bread are Aspergillus, Penicillium, Mucor, and Monilia sitophila.
Making bread
There are four main steps in making yeast bread.
Mixing
The first step is to mix the ingredients-flour, water, yeast, and salt-together. During mixing, starch granules absorb water and enzymes digest starch into sugars. The yeast feed on the sugars and produce carbon dioxide and alcohol. Glutenin proteins begin to react into gluten. Mixing can be done by hand, with an electric-mixer, or in a food processor. The later offer the advantage of limited oxygen exposure, which in excess can alter the pigments and flavor of the bread.
Kneading
The second step involves dough development. Through kneading, the dough is stretched, folded over, and compressed over and over. This manipulation strengthens the gluten network. It orients proteins to lay side by side which encourages them to form bonds. Overdevelopment of gluten causes bonds to break and turns the dough sticky and inelastic. Bewrae of overdeveloping the dough when kneading mechanically.
Kneading also aerates the dough. The more air pockets formed, the finer the texture of the final bread. Some breads call for minimal kneading. This results in fewer and larger air cells and their corresponding irregular and coarse texture. The gluten is weak and less developed, but it continues to develop through fermentation and can rise to an airy, tender crumb.
Fermentation (Rising)
The third step is fermentation, where the dough is set aside for yeast cells to produce carbon dioxide. As they do so and the carbon dioxide diffuses into air pockets, the dough rises. Yeast have the highest metabolic activity at 95 degrees F. This produces the greatest amount of carbon dioxide and metabolic by-products, some of which can be sour and unpleasant. For quick rising, it is suggested to keep fermentation at 80 degrees F for a couple of hours. Lower temperatures may extend the fermentation an hour or two, but generally produce more desirable flavors.
The end of fermentation is signaled by the dough's volume and the gluten matrix. Fully fermented dough is about twice its original size and has been stretched to its limit, so a finger impression remains when touched. Fermented doughs feel softer and are easier to handle than freshly kneaded dough.
Fermentation can be retarded by storing dough in the refrigerator. Yeast take 10 times as long to rise bread in cool temperatures. Retarding fermentation not only allows bakers to break up the work of making bread, but it has useful effects too. Long, slow fermentation allows greater flavor development by the yeast and bacteria in the dough. Cold dough handles easier without as much loss of leavening gas. The cycle of cooling and rewarming redistributes gases and promotes the development of a more open and irregular crumb structure.
Baking
The last step is baking. The kind of oven where a bread is baked has an important influence on the qualities of the finished loaf. Traditional bread ovens were made out of clay, stone, or brick. The baker preheated the oven by wood fire to temperatures up to 900 degrees F. The domed roof stored heat and radiated it down onto the loaves. The temperature declines during baking. The dough expands early on. The bread benefits from color and flavor development due to enhanced browning reactions.
Modern metal ovens are not ideal for bread making. The maximum cooking temperature is usually around 500 degrees F. Heat cannot be stored as well within their walls, so modern ovens maintain a heat source of gas or electrical elements. The necessary venting does not allow gas ovens to retain the loaves' steam. Some bakers use ceramic baking stones or ceramic oven inserts that mimic the traditional oven. The oven is preheated to its maximum temperature and provide more intensive even heat during baking.
Steam is important in the early baking stages because it increases the rate of heat transfer from the oven to the dough. As steam condenses onto the dough surface, it forms a thin film of water that temporarily prevents it from drying out into a crust. By doing so, it encourages the initial rapid expansion of the loaf. The hot water film eventually dries into an attractive glossy crust. Professional bakers often inject steam in the first minutes of baking. At home, one can spray water or throw ice cubes into the hot chamber to improve oven spring and crust gloss.
There are three stages of baking plus cooling.
Early baking: Oven Spring refers to the first 6-8 minutes of baking. Heat transfers first from the oven floor to the bottom of the dough, and to the top from the hot air and oven ceiling. Heat moves from the surface through the dough slowly through the gluten matrix; and rapidly through the gas network. Alcohol and water in the dough vaporize. The gas cells expand, and the dough rises. The better leavened the dough, the faster it cooks.
Mid-baking: The dough begins to transform into a sponge when the interior temperature of the dough reaches 155-180 degrees F/68-80 degrees C. At this range, the gluten proteins form strong cross-link bonds, the starch granules gelate, and the amylose molecules leak out. Gas pressure builds and ruptures the walls, turning the closed network of bubbles into an open network of pores similar to a sponge.
Late baking: Starch continues to gelate thoroughly. Continued cooking encourages surface browning reactions that improve color and flavor. Though limited to the crust, these reactions affecte the flavor of the whole loaf because their products diffuse downward. Bread is done when its crust has browned and the inner structure has set. Fully cooked bread feels light and hollow.
Cooling
The temperature varies inside a loaf immediately after being removed from the oven. During cooling, the differences even out. Most moisture loss occurs at this stage as moisture in the interior diffuses outward. Small rolls dry out the most, while large loaves the least. As temperature declines, starch granules become firmer, which later allows even slicing. This firming continues over the next day and starts the process of staling.
Mixing
The first step is to mix the ingredients-flour, water, yeast, and salt-together. During mixing, starch granules absorb water and enzymes digest starch into sugars. The yeast feed on the sugars and produce carbon dioxide and alcohol. Glutenin proteins begin to react into gluten. Mixing can be done by hand, with an electric-mixer, or in a food processor. The later offer the advantage of limited oxygen exposure, which in excess can alter the pigments and flavor of the bread.
Kneading
The second step involves dough development. Through kneading, the dough is stretched, folded over, and compressed over and over. This manipulation strengthens the gluten network. It orients proteins to lay side by side which encourages them to form bonds. Overdevelopment of gluten causes bonds to break and turns the dough sticky and inelastic. Bewrae of overdeveloping the dough when kneading mechanically.
Kneading also aerates the dough. The more air pockets formed, the finer the texture of the final bread. Some breads call for minimal kneading. This results in fewer and larger air cells and their corresponding irregular and coarse texture. The gluten is weak and less developed, but it continues to develop through fermentation and can rise to an airy, tender crumb.
Fermentation (Rising)
The third step is fermentation, where the dough is set aside for yeast cells to produce carbon dioxide. As they do so and the carbon dioxide diffuses into air pockets, the dough rises. Yeast have the highest metabolic activity at 95 degrees F. This produces the greatest amount of carbon dioxide and metabolic by-products, some of which can be sour and unpleasant. For quick rising, it is suggested to keep fermentation at 80 degrees F for a couple of hours. Lower temperatures may extend the fermentation an hour or two, but generally produce more desirable flavors.
The end of fermentation is signaled by the dough's volume and the gluten matrix. Fully fermented dough is about twice its original size and has been stretched to its limit, so a finger impression remains when touched. Fermented doughs feel softer and are easier to handle than freshly kneaded dough.
Fermentation can be retarded by storing dough in the refrigerator. Yeast take 10 times as long to rise bread in cool temperatures. Retarding fermentation not only allows bakers to break up the work of making bread, but it has useful effects too. Long, slow fermentation allows greater flavor development by the yeast and bacteria in the dough. Cold dough handles easier without as much loss of leavening gas. The cycle of cooling and rewarming redistributes gases and promotes the development of a more open and irregular crumb structure.
Baking
The last step is baking. The kind of oven where a bread is baked has an important influence on the qualities of the finished loaf. Traditional bread ovens were made out of clay, stone, or brick. The baker preheated the oven by wood fire to temperatures up to 900 degrees F. The domed roof stored heat and radiated it down onto the loaves. The temperature declines during baking. The dough expands early on. The bread benefits from color and flavor development due to enhanced browning reactions.
Modern metal ovens are not ideal for bread making. The maximum cooking temperature is usually around 500 degrees F. Heat cannot be stored as well within their walls, so modern ovens maintain a heat source of gas or electrical elements. The necessary venting does not allow gas ovens to retain the loaves' steam. Some bakers use ceramic baking stones or ceramic oven inserts that mimic the traditional oven. The oven is preheated to its maximum temperature and provide more intensive even heat during baking.
Steam is important in the early baking stages because it increases the rate of heat transfer from the oven to the dough. As steam condenses onto the dough surface, it forms a thin film of water that temporarily prevents it from drying out into a crust. By doing so, it encourages the initial rapid expansion of the loaf. The hot water film eventually dries into an attractive glossy crust. Professional bakers often inject steam in the first minutes of baking. At home, one can spray water or throw ice cubes into the hot chamber to improve oven spring and crust gloss.
There are three stages of baking plus cooling.
Early baking: Oven Spring refers to the first 6-8 minutes of baking. Heat transfers first from the oven floor to the bottom of the dough, and to the top from the hot air and oven ceiling. Heat moves from the surface through the dough slowly through the gluten matrix; and rapidly through the gas network. Alcohol and water in the dough vaporize. The gas cells expand, and the dough rises. The better leavened the dough, the faster it cooks.
Mid-baking: The dough begins to transform into a sponge when the interior temperature of the dough reaches 155-180 degrees F/68-80 degrees C. At this range, the gluten proteins form strong cross-link bonds, the starch granules gelate, and the amylose molecules leak out. Gas pressure builds and ruptures the walls, turning the closed network of bubbles into an open network of pores similar to a sponge.
Late baking: Starch continues to gelate thoroughly. Continued cooking encourages surface browning reactions that improve color and flavor. Though limited to the crust, these reactions affecte the flavor of the whole loaf because their products diffuse downward. Bread is done when its crust has browned and the inner structure has set. Fully cooked bread feels light and hollow.
Cooling
The temperature varies inside a loaf immediately after being removed from the oven. During cooling, the differences even out. Most moisture loss occurs at this stage as moisture in the interior diffuses outward. Small rolls dry out the most, while large loaves the least. As temperature declines, starch granules become firmer, which later allows even slicing. This firming continues over the next day and starts the process of staling.
Sunday, April 1, 2012
Handling and using yeast
Here are a few tips to keep in mind when handling yeast.
- Active dry can be used at 50% of the weight of fresh yeast. Instant dry can be used at 40% of the weight of fresh yeast.
- Yeast responds to warm water only.
- It is extremely sensitive to cold temperatures, too much air, and too much heat.
- Yeast dies within a couple of hours. Though most of the yeast is dead by the time the bread is placed in the oven to bake, there is still enough active yeast to produce carbon dioxide during the early stages of baking. Bread continues to rise in the early stages of baking, but as it progresses, the high temperature kills off the remainder yeast. Most bread deflates slightly toward the end of baking.
- A few things inhibit the yeast's ability to ferment. Salt, shortening, and animal fats can affect the rising action. Recipes that use yeast as the leavening agent, usually contain small amounts of salt and have some sugar for balance.
- Inactivated or dry yeast may at times be dead before use. To check for vitality, add a package to warm water and watch for gas production or expansion. Only after that, combine yeast with flour. Yeast will not activate if the water is too hot, too cold, or if a liquid other than water is used (i.e. milk).
Baker's yeast
There are several types of Baker's yeast:
Cake Yeast, also known as wet, fresh, or compressed yeast, is characterized by a high moisture content. Cake yeast is processed one step further than cream yeast and is taken directly from the fermentation vat. the yeast cells are alive and produce more leaving gas than other forms. It is very perishable and needs to be refrigerated. Shelf life is short, between 2 and 8 weeks.
Active Dry Yeast is yeast is processed one step further than Cake Yeast. It is taken from the fermentation tank and dried into granules with a protective coating of yeast debris. Due to the low moisture content, the yeast is in a semi-dormant state and is therefore more stable than cake yeast. At the time of usage, the baker needs to reactivate the yeast by soaking them in warm water, 105-110 degrees F/41-43 degrees C, before adding mixing into the dough. The shelf life of an unopened package extends from a few months up to 2 years.
Instant Yeast, also known as "fast-rising" or "fast-acting" yeast, is a "dry" yeast that can shorten the rising time in traditional baking by as much as 50%. This yeast is dried quickly and into porous rods instead of granules. This rod formation allows them to take up water more rapidly. Instant yeast does not need to be prehydrated and usually produces more carbon dioxide gas than active dry yeast The shelf life of an unopened package extends up to 2 years.
Cake Yeast, also known as wet, fresh, or compressed yeast, is characterized by a high moisture content. Cake yeast is processed one step further than cream yeast and is taken directly from the fermentation vat. the yeast cells are alive and produce more leaving gas than other forms. It is very perishable and needs to be refrigerated. Shelf life is short, between 2 and 8 weeks.
Active Dry Yeast is yeast is processed one step further than Cake Yeast. It is taken from the fermentation tank and dried into granules with a protective coating of yeast debris. Due to the low moisture content, the yeast is in a semi-dormant state and is therefore more stable than cake yeast. At the time of usage, the baker needs to reactivate the yeast by soaking them in warm water, 105-110 degrees F/41-43 degrees C, before adding mixing into the dough. The shelf life of an unopened package extends from a few months up to 2 years.
Instant Yeast, also known as "fast-rising" or "fast-acting" yeast, is a "dry" yeast that can shorten the rising time in traditional baking by as much as 50%. This yeast is dried quickly and into porous rods instead of granules. This rod formation allows them to take up water more rapidly. Instant yeast does not need to be prehydrated and usually produces more carbon dioxide gas than active dry yeast The shelf life of an unopened package extends up to 2 years.
Yeast metabolism
Baker's and brewer's yeast is Saccharomyces Cerevisiae, also referred to as the "sugar-eating fungus."
Yeasts feast on glucose and fructose from sugar, and on maltose from the broken-down starch granules in the flour.
Yeast metabolize sugars for energy and produce ethyl alcohol and carbon dioxide following this equation:
C6H12O6 -----> 2(CH3CH2OH) + 2(CO2) + ATP
In making beer and wine, the carbon dioxide escapes the liquid and concentrates the alcohol. In making bread, carbon dioxide and alcohol become trapped in the dough. The flexibility of the dough accomodates the expanding gas by inflating or "rising." The ethyl alcohol, along with other by-products of fermentation, give yeast-leavened breads their typical aroma. At the time of baking, the heat expells both carbon dioxide and alcohol from the dough, leaving a flavorful network of empty air pockets.
A small amount of added table sugar increases yeast activity, whereas a large amount decreases it. Too much sugar dehydrates the yeast. To compensate, bakers of sweet breads add more yeast than ordinary, and allow longer times for the bread to rise.
Yeast are also sensitive to salt, and are greatly affected by temperature. Cells grow and produce gas most rapidly at around 95 degrees F/35 degrees C.
Yeasts feast on glucose and fructose from sugar, and on maltose from the broken-down starch granules in the flour.
Yeast metabolize sugars for energy and produce ethyl alcohol and carbon dioxide following this equation:
C6H12O6 -----> 2(CH3CH2OH) + 2(CO2) + ATP
In making beer and wine, the carbon dioxide escapes the liquid and concentrates the alcohol. In making bread, carbon dioxide and alcohol become trapped in the dough. The flexibility of the dough accomodates the expanding gas by inflating or "rising." The ethyl alcohol, along with other by-products of fermentation, give yeast-leavened breads their typical aroma. At the time of baking, the heat expells both carbon dioxide and alcohol from the dough, leaving a flavorful network of empty air pockets.
A small amount of added table sugar increases yeast activity, whereas a large amount decreases it. Too much sugar dehydrates the yeast. To compensate, bakers of sweet breads add more yeast than ordinary, and allow longer times for the bread to rise.
Yeast are also sensitive to salt, and are greatly affected by temperature. Cells grow and produce gas most rapidly at around 95 degrees F/35 degrees C.
History of yeast
The history of yeast dates further back than written language. Egyptian hieroglyphics, dating back 5,000 years, depic the Ancient using yeast for alcohol fermentation as well as a leavening agent. It is believed that early fermentation occurred naturally through contamination of fruit and flour. The Ancient used yeast even though they did not understand it. The faculties of yeast were often attributed to magic.
Leaven, as it is described in the Bible, was a soft dough-like medium. A small portion was reserved as a starter dough for new bread. By saving "good" batches, man naturally selected the best yeast for his baking/fermentation needs. Yeast is therefore considered the first industrial microorganism.
Yeast was not identified as the living organism responsible for fermentation and leavening until after the invention of the microscope in the 1600s and the work of Louis Pasteur in the 1860s. Isolation of pure cultures gave way to commercial production and manufacturing starting at the turn of the 20th century.
Leaven, as it is described in the Bible, was a soft dough-like medium. A small portion was reserved as a starter dough for new bread. By saving "good" batches, man naturally selected the best yeast for his baking/fermentation needs. Yeast is therefore considered the first industrial microorganism.
Yeast was not identified as the living organism responsible for fermentation and leavening until after the invention of the microscope in the 1600s and the work of Louis Pasteur in the 1860s. Isolation of pure cultures gave way to commercial production and manufacturing starting at the turn of the 20th century.
Kinds of flour
Most flours available are labeled according to purpose and usually do not include information about the type of wheat they contain. Flour compositions tend to be blends and can vary from region to region. For example, "all-purpose" flour in the South and Pacific Northwest tends to have lower protein content than flour in other parts of the US and Canada. For this reason, recipes developed in the South turn differently when prepared in other regions unless care is taken to approximate the original. Still, here are some guidelines:
- Whole wheat flours are high in protein; with a high concentration of that protein steming from the germ and aleurone layer, which do not form gluten well. Therefore, they make flavorful but dense bread.
- Bread flours are high in strong gluten proteins. They give the lightest, highest, chewiest loaf breads.
- Pastry flours contain low levels of weak gluten protein. They make tender baked goods.
- Cake flour is soft, low-protein, finely-milled, and strongly bleached with chlorine dioxide or chlorine gas. This treatment enhances the starch granules' ability to absorb water and swell in high-sugar batters. It also helps fat bind more readily to the starch granules' surface, which helps disperse the fat more evenly. Lastly, chlorination also gives the flour an acidic pH. Packaged cake mixes have a high sugar to flour ratio; sugar can outweigh flour by as much as 40%. This allows cakes to have a distinctively light and moist texture.
- "Self-rising" flours contain baking powder (1 1/2 tsp baking powder per cup) and therfore do not require added leavening.
- "Instant" flours are low protein flours whose starch granules have been precooked and dried. Water is more able to penetrate the granules during cooking, such that they are well suited for tender pastries and last-minute thickening of sauces and gravies.
- For pastry flour, add one part by weight of starch to two parts of all-purpose flour.
- For all purpose flour, add one-quarter part of gluten to two parts pastry flour.
Flour
The qualities of flour are determined by the type of wheat (or grain) used and the method of milling.
Milling is the process by which the wheat kernel is broken down and sifted into small particles. Refined flour is sieved to remove the germ and bran layers from the endosperm of the grain. Bran and germ are rich in nutrients and flavor, but they spoil quickly and interfere with the formation of continuous, strong gluten. In conventional milling, grooved metal rollers shear open the grain, squeeze out the germ, and scrape the endosperm away to be ground, sieved, and reground until it attains a specific particle size. Stone grinding is not as widely used, but it crushes the whole grain more thoroughly before sieving, which allows some of the germ and bran to end up in the refined flour. This makes stone ground flour more nutritious and flavorful, but gives it a shorter shelf life.
Freshly milled flour makes weak gluten and dense loaves. Flour needs to be aged to improve its baking qualities. As it ages, flour becomes exposed to oxygen which enhances its ability to make long gluten chains. Oxygen frees sulfur groups at the end of glutenin proteins that allows them to better react with each other. Manufacturers have supplemented flour with oxidizing agents such as ascorbic acid and azodicarbonamide to speed this process. Traditional air-aging also had the secondary effect of lightening the flour, rendering it whiter as yellow xanthophyll pigments oxidized to colorless compounds. To obtain similar whiteness, bleaching flour with azodicarbonamide and peroxide has become common practice in the United States. However, there have been concerns about this chemical alteration. Hence, bleaching is not allowed in Europe.
Gluten proteins and starch account for 90% of flour weight, but there are two minor components that have important effects, fats and enzymes. Fat accounts for only 1% of flour but it is essential to the development of raised bread. Fats help stabilize the bubble walls, help soften the bread structure, and slow staling. Enzymes break down starch to simple sugars that are more easily digested by yeast. Manufacturers have started to add enzymes extracted and purified from microscopic molds ("fungal amylase") to increase enzymatic activity in a predictable pattern.
Milling is the process by which the wheat kernel is broken down and sifted into small particles. Refined flour is sieved to remove the germ and bran layers from the endosperm of the grain. Bran and germ are rich in nutrients and flavor, but they spoil quickly and interfere with the formation of continuous, strong gluten. In conventional milling, grooved metal rollers shear open the grain, squeeze out the germ, and scrape the endosperm away to be ground, sieved, and reground until it attains a specific particle size. Stone grinding is not as widely used, but it crushes the whole grain more thoroughly before sieving, which allows some of the germ and bran to end up in the refined flour. This makes stone ground flour more nutritious and flavorful, but gives it a shorter shelf life.
Freshly milled flour makes weak gluten and dense loaves. Flour needs to be aged to improve its baking qualities. As it ages, flour becomes exposed to oxygen which enhances its ability to make long gluten chains. Oxygen frees sulfur groups at the end of glutenin proteins that allows them to better react with each other. Manufacturers have supplemented flour with oxidizing agents such as ascorbic acid and azodicarbonamide to speed this process. Traditional air-aging also had the secondary effect of lightening the flour, rendering it whiter as yellow xanthophyll pigments oxidized to colorless compounds. To obtain similar whiteness, bleaching flour with azodicarbonamide and peroxide has become common practice in the United States. However, there have been concerns about this chemical alteration. Hence, bleaching is not allowed in Europe.
Gluten proteins and starch account for 90% of flour weight, but there are two minor components that have important effects, fats and enzymes. Fat accounts for only 1% of flour but it is essential to the development of raised bread. Fats help stabilize the bubble walls, help soften the bread structure, and slow staling. Enzymes break down starch to simple sugars that are more easily digested by yeast. Manufacturers have started to add enzymes extracted and purified from microscopic molds ("fungal amylase") to increase enzymatic activity in a predictable pattern.
Saturday, March 31, 2012
Types of wheat
Several types of wheat are grown today. They differ in their protein content and growing habit.
The most common species of bread wheat is Triticum aestivum. This wheat is high in protein and forms a strong gluten. Most of the wheat produced in North America is Hard wheat, which constitutes 75% of the total crop. Soft wheat makes up 20% and have less protein and form weaker gluten. Durum wheat is a different species that is mainly used to make pasta.
The classification of wheat growth habits and kernel color. Spring wheats are sown in spring and harvested in fall. Winter wheats are sown in the fall and harvested in summer. Red wheat gets its color from the presence of phenolic compounds, which the White wheat variety lacks, and it is often preferred for its sweeter taste.
The most common species of bread wheat is Triticum aestivum. This wheat is high in protein and forms a strong gluten. Most of the wheat produced in North America is Hard wheat, which constitutes 75% of the total crop. Soft wheat makes up 20% and have less protein and form weaker gluten. Durum wheat is a different species that is mainly used to make pasta.
The classification of wheat growth habits and kernel color. Spring wheats are sown in spring and harvested in fall. Winter wheats are sown in the fall and harvested in summer. Red wheat gets its color from the presence of phenolic compounds, which the White wheat variety lacks, and it is often preferred for its sweeter taste.
Gas bubbles
Breads and cakes are aerated to the point that as much as 80% of their volume is empty space. Bakers use yeast and chemical leavenings to enhance the bubbles in their baked goods. It is important to note that leavenings do not create all of the gas present in the batter or dough. In fact, most of the bubbles form from air introduced when the baker kneads the dough, creams the butter and sugar, or whips the eggs. The carbon dioxide produced by leavenings is released into the water phase of the dough, diffuses to the bubbles already present, and merely enlarges them. Therefore, the initial aeration of doughs and batters strongly influence the final texture of the baked goods.
Starch
The word starch comes from a German root that means "to stiffen or make rigid." While starch has been used in paper making and textiles to stiffen, it has also served the same purpose bread making. Gluten proteins make only 10% of flour by weight, whereas starch makes up 70%. Starch granules absorb water, swell, and set to form the rigid bulk. They account for more than half the volume of dough. Though starch provides gives structure to bread, it also tenderizes it by penetrating and breaking up the gluten network. As carbon dioxide is produced, the rigidity of starch-formed walls stops the expansion of the bubbles. Pressure forces the water vapor inside to pop the bubbles and allow carbon dioxide to escape. As it does, a spongy network is left behind. This accounts for the crumbly texture of bread.
Starch is particularly important in batters where gluten proteins are too dispersed in water and sugar to contribute to the solidity of the cake.
Starch is particularly important in batters where gluten proteins are too dispersed in water and sugar to contribute to the solidity of the cake.
Friday, March 30, 2012
Dough, batter, and texture
Wheat flour has characteristic liveliness and cohesiveness that set it apart from other cereal doughs. These characteristics make it possible for light, delicate loaves, flaky pastries, and silken pastas.
There are three basic elements at work: water, the flour's gluten proteins, and its starch granules. When integrated, these elements create cohesive mass.
Mixture of flour and water is called a dough or batter depending on the relative portions of the ingredients. According to Harold McGee, "doughs contain more flour than water and are stiff enough to be manipulated by hand. All the water is bound to the gluten proteins and to the surfaces of the starch granules, which are embedded in the semisolid gluten-water matrix. Batters contain more water than flour and are loose enough to pour. Much of the water is free liquid, and both gluten proteins and starch granules are dispersed in it." Once cooked, the starch granules absorb water, swell, and create a permanent sponge-like structure made up of millions of tiny air pockets.The term crumb refers to this network. Crust is the outer surface.
The texture of breads and cakes is light and tender because the protein-starch mass is divided up by millions of tiny bubbles. Pastries are flaky and tender because the protein-starch mass is interrupted by hundreds of layers of fat.
There are three basic elements at work: water, the flour's gluten proteins, and its starch granules. When integrated, these elements create cohesive mass.
Mixture of flour and water is called a dough or batter depending on the relative portions of the ingredients. According to Harold McGee, "doughs contain more flour than water and are stiff enough to be manipulated by hand. All the water is bound to the gluten proteins and to the surfaces of the starch granules, which are embedded in the semisolid gluten-water matrix. Batters contain more water than flour and are loose enough to pour. Much of the water is free liquid, and both gluten proteins and starch granules are dispersed in it." Once cooked, the starch granules absorb water, swell, and create a permanent sponge-like structure made up of millions of tiny air pockets.The term crumb refers to this network. Crust is the outer surface.
The texture of breads and cakes is light and tender because the protein-starch mass is divided up by millions of tiny bubbles. Pastries are flaky and tender because the protein-starch mass is interrupted by hundreds of layers of fat.
Controlling Gluten Strength
Gluten development and strength varies according to the product desired. For yeast-leavened breads and puffs, bakers need the tough qualities of gluten. For goods such as pastries, griddle cakes, and cookies, gluten needs to be controlled to avoid undesirable toughness. Here are some techniques and ingredients that affect gluten/gluten strength:
- Flour - high protein flour produces strong gluten, low protein and cake flours produce a weak one. Durum semolina produces a strong, plastic gluten preferable for pasta.
- Oxidizing substances - oxygen frees the sulfur groups at the end of glutenin proteins such that they are more available to react and form longer gluten chains that give dough greater elasticity and strength.
- Water - little water underdevelops gluten and forms a crumbly texture; a lot of water makes for less concentrated gluten and a softer, moister dough.
- Stirring/Kneading - mechanical actions stretch and organize the gluten network.
- Salt - the electrically charged ions of salt cluster around charged portions of the glutenin proteins allowing proteins to come closer to each other and form stronger bonds. Salt geratly strengthens the gluten network.
- Sugar - limits gluten development by diluting the flour proteins.
- Fats and oils - weaken gluten by bonding huydrophobic amino acids, thus preventing the proteins from further bonding to each other.
- Acidity - weakens the gluten network by increasing the repulsive forces between chains. This action is somewhat opposite of the effects of salt.
Gluten
Gluten proteins form long chains that stick to each other.
Gluten is an interconnected network of coiled chains made up of gliadins and glutenin proteins. Each of these proteins is around 1000 amino acids long. Gliadin chains fold onto themselves in a compact mass. These proteins act as ball bearings for glutenin proteins. Glutenins have sulfur-containing amino acids at the end of their chains. Where gliadins only form weak bonds, glutenins form strong sulfur-sulfur bonds with each other, forming long chains. Amino acids in the glutenin chains also form weak temporary hydrophobic bonds that form the coil. The coiled and kinky gluten molecules makes the dough elastic. Thus when dough gets stretched out, the coils extend. When the tension is released, the kinks and coils reform, and the dough shrinks back to its original shape. These properties of plasticity and elasticity allow wheat dough to accomodate carbon dioxide gas without allowing it to escape.
Gluten is an interconnected network of coiled chains made up of gliadins and glutenin proteins. Each of these proteins is around 1000 amino acids long. Gliadin chains fold onto themselves in a compact mass. These proteins act as ball bearings for glutenin proteins. Glutenins have sulfur-containing amino acids at the end of their chains. Where gliadins only form weak bonds, glutenins form strong sulfur-sulfur bonds with each other, forming long chains. Amino acids in the glutenin chains also form weak temporary hydrophobic bonds that form the coil. The coiled and kinky gluten molecules makes the dough elastic. Thus when dough gets stretched out, the coils extend. When the tension is released, the kinks and coils reform, and the dough shrinks back to its original shape. These properties of plasticity and elasticity allow wheat dough to accomodate carbon dioxide gas without allowing it to escape.
Bread 101
What qualifies as bread? On the most basic level, bread is the result from cooking a mixture of milled grains and water. Here is a quick run down of the most common ingredients in bread:
- Flour - Wheat flour is most commonly used in raised bread because it contains two proteins, glutenin and gliadin, which form gluten when combined with water. As the baker kneads the dough, the gluten develops and becomes elastic. This elasticity allows the incorporation of carbon dioxide gas into the dough.
- Starch is a carbohydrate that makes up 70% of the flour by weight. Starch granules release sugars that the yeast feed on. Starch reinforces gluten and absorbs water during baking, helping the gluten contain the carbon dioxide.
- Water is the most important liquid in bread. It dissolves and activates yeast and blends with the flour to create gluten.
- Yeast is a live, single-cell fungus that begins feeding on the sugars in flour and releases the carbon dioxide that makes bread rise. Yeast also adds many of the flavors and aromas associated with bread.
- Baking powder and baking soda are chemical leavenings that participate in the reactions between acidic and alkaline compounds that produce the carbon dioxide necessary to inflate dough or batter. These chemical leavenings act much faster than yeast, and are best used in quick breads.
- Salt slows rising time, which allows the flavor of the dough to develop. Salt also adds structure to the dough by strengthening the gluten, which keeps the carbon dioxide bubbles from expanding too rapidly.
- Eggs add food value, color, and flavor. They also make the crumb fine and the crust tender. Eggs add richness and protein.
- Fat in the form of butter, margarine, shortening or oil add flavor and moisture to bread. Fat slows moisture loss and helps bread stay fresh longer.
- Other liquids such as milk, buttermilk, cream or juice may be added for flavor or to enhance texture. Only add warm liquids to dry ingredients. Too cool liquids slow or stop yeast action. Too hot liquids destroy the yeast and prevent bread from rising.
- Sweetners such as sugar, brown sugar, honey, molasses, jams, and dried fruits may be used to add flavor and color to the crust.
Thursday, March 29, 2012
History of bread
There is no other food as important in the history of humanity as is bread. As Harold McGee expresses in his book, On Food and Cooking, bread took the center stage of life early on as it was "a startling sign of the natural's world hidden potential for being transformed, and [man’s] own ability to shape natural materials to human desires."
Bread and bread-making lore infiltrated language and culture early on. Words such as "Lord" come from the Anglo-Saxon hlaford, which means "loaf ward" or the master who supplies food. The word "Lady" derives its meaning from “loaf kneader.” Even the word "companion" can trace its meaning to “one who shares bread.”
The development of bread in pre-historic times is thought to have come about in two ways: First, by cooking pastes of crushed grain and water to form flatbreads; and second, from setting the paste aside, allowing it to ferment, and baking it in an enclosed oven to form raised breads.
Examples of wheat flatbreads include Middle Eastern lavash, Greek pita, Indian roti and chapatti. Latin American tortilla and North American johnnycake are flatbreads made from maize.
The history of wheat bread dates to 8000 BCE. The earliest record of leaven bread comes from the Egyptians, around 4000 BCE. Yeast production, though not entirely understood, was a notable skill. By 300 BCE, it had become a specialized profession in Ancient Egypt.
The Greeks mark on bread was one of whiteness. The early Greeks developed ways to partly refine grain in a way that it produced white bread. The Romans treasured wheat bread enough that wheat was imported from Africa to satisfy the demand of the Empire.
The 17th century brought improvements in milling and in per capita income that led to a wide availability of whiter bread and the dissolution of the brown guild. The Renaissance gave birth to pastries.
In the 1800s, most bread was still baked in communal ovens. The Industrial Revolution led to bakeries, and adulterated flour with whiteners (alum) and fillers (chalk, ground animal bones). Such developments led to the decline of domestic baking.
Furthermore, some innovations came to leaving. Pearlash, a precursor to baking soda and baking powders, appeared around 1790s. Baking powder and baking soda appeared 1830-1850s. Their development increased the ability to leaven doughs that yeast could not, such as fluid cake batters and sweet cookie doughs.
Twentieth century industrialization and modernization led to a decline in the per capita consumption of bread. As incomes rose, more people had ability to eat meat, and high-fat, high-sugar pastries and cakes. Bread was no longer the staff of life. Bread making became more industrialized in that most bread was made in large central factories, not local bakeries. The result was affordable, white bread with uncharacteristic flavor.
Europeans and North Americans began to eat more bread in the 1980s. Traditional bread making returned. Small bakeries began to produce bread with less refined grain, building flavor with long, slow fermentation, and baking small batches in brick ovens that produced small, dark loaves. The Japanese invented the home bread machine. Today, small fraction of bread is artisan. But manufacturers have started to ship partly baked and frozen loaves to supermarkets. These loaves are rebaked locally and sold while still crusty and flavorful. Currently, we are experiencing a return to flavor and texture characteristic of traditional bread.
Bread and bread-making lore infiltrated language and culture early on. Words such as "Lord" come from the Anglo-Saxon hlaford, which means "loaf ward" or the master who supplies food. The word "Lady" derives its meaning from “loaf kneader.” Even the word "companion" can trace its meaning to “one who shares bread.”
The development of bread in pre-historic times is thought to have come about in two ways: First, by cooking pastes of crushed grain and water to form flatbreads; and second, from setting the paste aside, allowing it to ferment, and baking it in an enclosed oven to form raised breads.
Examples of wheat flatbreads include Middle Eastern lavash, Greek pita, Indian roti and chapatti. Latin American tortilla and North American johnnycake are flatbreads made from maize.
The history of wheat bread dates to 8000 BCE. The earliest record of leaven bread comes from the Egyptians, around 4000 BCE. Yeast production, though not entirely understood, was a notable skill. By 300 BCE, it had become a specialized profession in Ancient Egypt.
The Greeks mark on bread was one of whiteness. The early Greeks developed ways to partly refine grain in a way that it produced white bread. The Romans treasured wheat bread enough that wheat was imported from Africa to satisfy the demand of the Empire.
The 17th century brought improvements in milling and in per capita income that led to a wide availability of whiter bread and the dissolution of the brown guild. The Renaissance gave birth to pastries.
In the 1800s, most bread was still baked in communal ovens. The Industrial Revolution led to bakeries, and adulterated flour with whiteners (alum) and fillers (chalk, ground animal bones). Such developments led to the decline of domestic baking.
Furthermore, some innovations came to leaving. Pearlash, a precursor to baking soda and baking powders, appeared around 1790s. Baking powder and baking soda appeared 1830-1850s. Their development increased the ability to leaven doughs that yeast could not, such as fluid cake batters and sweet cookie doughs.
Twentieth century industrialization and modernization led to a decline in the per capita consumption of bread. As incomes rose, more people had ability to eat meat, and high-fat, high-sugar pastries and cakes. Bread was no longer the staff of life. Bread making became more industrialized in that most bread was made in large central factories, not local bakeries. The result was affordable, white bread with uncharacteristic flavor.
Europeans and North Americans began to eat more bread in the 1980s. Traditional bread making returned. Small bakeries began to produce bread with less refined grain, building flavor with long, slow fermentation, and baking small batches in brick ovens that produced small, dark loaves. The Japanese invented the home bread machine. Today, small fraction of bread is artisan. But manufacturers have started to ship partly baked and frozen loaves to supermarkets. These loaves are rebaked locally and sold while still crusty and flavorful. Currently, we are experiencing a return to flavor and texture characteristic of traditional bread.
Lesson 5: Challah (Braided) Bread
This week I am going to explore all things related to bread. The topics include:
- All things bread
- Gluten
- Flour
- Yeast
- Salt
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