The Baking Process
The changes that take place to a dough or batter while it cooks is called the Baking Process. Essentially all baked products (cookies, cakes and breads) cook in the same way. It is important for the baker to learn these steps so that they can control them as needed.
There are seven stages to the baking process. They are:
1. Formation and Expansion of Gases
The gases responsible for leavening baked goods are
Carbon Dioxide-which is released by the action of yeast, baking soda or baking powder
Air- which is incorporated into a dough or batter in the mixing process
Steam- which is formed during baking
Some gases such as air in cake batters and carbon dioxide in proofed bread dough are already present before baking. As they are heated, these gases expand and leaven the product.
Some gases are not formed until heat is applied. Yeast and baking powder form gases rapidly when first placed in the oven (cookies, tea biscuits). Steam is also formed as the moisture in the dough is heated (eg. cream puffs)
2. Trapping of the Gases in the Air Cells
As the gases are formed and expand, they are trapped in the stretchable proteins of the dough. The proteins generally consist of gluten and sometimes egg protein. Without this protein the gases would escape and the product would not rise well. This is why bread made with flour other than wheat (and therefore with little gluten) tends to be heavy (pumpernickel).
3. Gelatinization of Starches
The starches absorb moisture, expand, and become firmer. This contributes to structure. Gelatinization of starches begins at about 140F (60c).
4. Coagulation of Proteins
Gluten and egg proteins solidify when they reach a temperature of approximately 165F (74C). This process gives most of its structure to baked goods.
***Correct baking temperature is important***
If the temperature is too high, coagulation starts too soon, before the expansion of gases reaches its peak. The result is a product with poor volume and a split crust. If the temperature is too low, the proteins do not coagulate soon enough and the resulting product may collapse.
5. Evaporation of Some of the Water
This takes place throughout the baking process. If a particular weight is required of the baked product (e.g. 1 lb bread loaf), the loss of moisture must be factored in when scaling the dough (18 oz raw dough). The percentage of weight loss varies greatly depending on factors such as surface area to volume, baking time, and whether the item is baked in a pan or directly on the oven hearth.
6. Melting of Shortenings
Different shortenings melt and release trapped gasses at different temperatures, so the proper shortening should be selected for each product.
7. Crust Formation and Browning
A crust is formed as water evaporates from the surface and leaves it dry. Browning occurs when sugars caramelize and starches and sugars undergo certain chemical changes caused by heat. This contributes to flavour. Milk sugar and egg increase browning.
Staling
Staling is the change in texture and aroma of baked goods due to a change of structure and a loss of moisture by the starch granules. Staling begins almost as soon as the baked good is removed from the oven. There are two factors to staling. The first is a loss of moisture. The second is chemical staling. Chemical staling (called starch retrogradation) is a chemical change to the structure of the starch. This means that even a well wrapped baked good will undergo chemical staling. Chemical staling can be partially reversed by heating but must only be used if the product is to be served immediately as the result of heating will increase the loss of moisture in the baked good. Chemical staling is rapid at refrigerator temperatures but nearly stops at freezer temperatures.
Loss of crispness is essentially the opposite of staling. This is when a product absorbs moisture. Loss of crispness is a particular problem in low moisture items such as cookies and pie crusts. Cookies should be placed in airtight containers and pie crusts should be filled as close to serving time as possible.
There are three main techniques used to slow staling. They are protecting the product from air, adding moisture retainers (fats and sugars) to the formula and freezing.
There are seven stages to the baking process. They are:
1. Formation and Expansion of Gases
The gases responsible for leavening baked goods are
Carbon Dioxide-which is released by the action of yeast, baking soda or baking powder
Air- which is incorporated into a dough or batter in the mixing process
Steam- which is formed during baking
Some gases such as air in cake batters and carbon dioxide in proofed bread dough are already present before baking. As they are heated, these gases expand and leaven the product.
Some gases are not formed until heat is applied. Yeast and baking powder form gases rapidly when first placed in the oven (cookies, tea biscuits). Steam is also formed as the moisture in the dough is heated (eg. cream puffs)
2. Trapping of the Gases in the Air Cells
As the gases are formed and expand, they are trapped in the stretchable proteins of the dough. The proteins generally consist of gluten and sometimes egg protein. Without this protein the gases would escape and the product would not rise well. This is why bread made with flour other than wheat (and therefore with little gluten) tends to be heavy (pumpernickel).
3. Gelatinization of Starches
The starches absorb moisture, expand, and become firmer. This contributes to structure. Gelatinization of starches begins at about 140F (60c).
4. Coagulation of Proteins
Gluten and egg proteins solidify when they reach a temperature of approximately 165F (74C). This process gives most of its structure to baked goods.
***Correct baking temperature is important***
If the temperature is too high, coagulation starts too soon, before the expansion of gases reaches its peak. The result is a product with poor volume and a split crust. If the temperature is too low, the proteins do not coagulate soon enough and the resulting product may collapse.
5. Evaporation of Some of the Water
This takes place throughout the baking process. If a particular weight is required of the baked product (e.g. 1 lb bread loaf), the loss of moisture must be factored in when scaling the dough (18 oz raw dough). The percentage of weight loss varies greatly depending on factors such as surface area to volume, baking time, and whether the item is baked in a pan or directly on the oven hearth.
6. Melting of Shortenings
Different shortenings melt and release trapped gasses at different temperatures, so the proper shortening should be selected for each product.
7. Crust Formation and Browning
A crust is formed as water evaporates from the surface and leaves it dry. Browning occurs when sugars caramelize and starches and sugars undergo certain chemical changes caused by heat. This contributes to flavour. Milk sugar and egg increase browning.
Staling
Staling is the change in texture and aroma of baked goods due to a change of structure and a loss of moisture by the starch granules. Staling begins almost as soon as the baked good is removed from the oven. There are two factors to staling. The first is a loss of moisture. The second is chemical staling. Chemical staling (called starch retrogradation) is a chemical change to the structure of the starch. This means that even a well wrapped baked good will undergo chemical staling. Chemical staling can be partially reversed by heating but must only be used if the product is to be served immediately as the result of heating will increase the loss of moisture in the baked good. Chemical staling is rapid at refrigerator temperatures but nearly stops at freezer temperatures.
Loss of crispness is essentially the opposite of staling. This is when a product absorbs moisture. Loss of crispness is a particular problem in low moisture items such as cookies and pie crusts. Cookies should be placed in airtight containers and pie crusts should be filled as close to serving time as possible.
There are three main techniques used to slow staling. They are protecting the product from air, adding moisture retainers (fats and sugars) to the formula and freezing.