Saturday, 3 August 2013

The Many Roles Water Plays.

What is the purpose of water in bread making?
Water provides for gluten formation in flour, yeast fermentation and reproduction and gives the dough consistency. Water serves as a solvent and dispersing agent for salt, sugar, and yeast that are necessary for the fermentation. The next essential role is its function in emulsifying all these substances throughout the dough during kneading. Water is also needed for swelling and gelatinisation of the starch. This in its turn improves the easy digestion of the bread. The distribution of the heat through the bread during baking is done by water in the dough. And finally water influences the sensory properties of the bread.

The formation of the dough Without water, the formation of dough would be impossible.The two main components of flour are the starch and the protein. When water is mixed with flour, it will first hydrate the particles of starch and start the formation of the dough. Then protein will start to absorb some water and begin to form the gluten of the dough. The wetted starch is incorporated into the gluten by the mixing process and the result is the uniform, pliable, plastic substance called dough.
But since there is no gluten in the flours used for gluten free baking, this is where binders such as psyllium adopt the glutens role in dough and using high protein gluten free flours mixed with starches mimics the components of wheat flour. It is important to note that protein will absorb water slower compared to the starch. This is why it is essential for the baker to have a sufficient incorporation time. This will insure proper gluten formation and proper binding of the flour components.

The effect on dough fermentation
Water plays an important part in the fermentation of the dough mainly from two standpoints.
(a) Water makes possible the pliable and extensible properties of the dough so that in this form it can be raised by the carbon dioxide gas resulting from yeast activity.
(b) In order to enable the yeast enzymes to function, it is necessary that the required food substances supporting the yeast in the dough, first become dissolved in water of the dough so that in this form, they can diffuse through the wall or membrane surrounding the yeast cell and thus become available for direct utilization by the yeast throughout the entire panary fermentation process. The activity of the yeast itself also requires the presence of water. When this is incorporated into the dough batch in the mixer, the yeast cells are completely and uniformly distributed throughout the entire mass of dough.

The amount controls the dough consistency
Depending on the desired final dough consistency (most of the time in direct relation with the mixing time, fermentation time and final product characteristics) the amount of water could be adjusted in the formula.
A large amount of water will create dough with a soft consistency while a lower amount of water will generate dough with a stiffer consistency. Remember that slack doughs will ferment faster than stiff doughs.
Consistency is sometimes difficult to assess with a specific amount or consistent percentage of water, since flour characteristics can affect it in a tremendous way. A better way would be to describe it using the feeling of the dough. This notion of consistency is very important since it will also directly affect gluten and final product characteristics:
Softer dough will create a weaker gluten structure, more extensible and less elastic. This type of dough will benefit from long fermentation time and sometimes folds during the first fermentation. Generally speaking, the final product will have a more open and chewy crumb structure and a more pronounced flavor.
Stiffer dough will create a stronger gluten structure, less extensible and more elastic. In this case, shorter fermentation time will be more appropriate to avoid an excess of strength during the shaping. The final product will have a tighter cell structure and if no pre-fermentation is used a flavor a little bit more bland.

Water controls the temperature of the dough
Specific final dough temperature is crucial in order to obtain good fermentation activity. Because water is the easiest ingredient to change in temperature, the baker uses it to control final dough temperature. Water temperature will have a direct effect on the final dough temperature. Logically, a cold water will generate cooler dough temperature, while warmer water will create warmer dough temperature. Cooler water slows down the rise of the dough. Water needs to be used at the temperature of bathwater: a little higher than body temperature to activate the yeast, which in turn produces gas and stretches the dough.

The handling of the dough
The role of water is definitively very important during mixing. A dough with a good consistency will lead to good final products characteristics while a dough too stiff or too soft will probably require some adjustments during the baking process and potentially compromising final product quality. This is why the mixing of the dough requires a lot of attention. The feeling of the surface of the dough during dividing, preshaping and shaping is mostly due to different level of concentration of water.
Sticky dough will have a lot of water concentrated on its surface, making it more challenging to process.
Dry dough is the result of water evaporation on the surface of the dough, leading to poor final product characteristics (poor crust color, poor crumb characteristics…). The goal is to control these movements of water to keep the dough in good condition. For example, cover the dough with plastic if air is dry or if there are any drafts in the area.
On the other hand, if the dough feels sticky, due to an excess of air moisture, it will have to be kept uncovered with some air circulation around it.

Mineral content of water
The mineral content will determine the hardness and the softness of the water. The main ones being calcium, magnesium and sodium. Hard water contains a large amount of minerals while soft water contains a more limited amount of minerals.
Dough characteristics could be affected by the minerals content of the water: minerals will be used as nutrients by the yeast, therefore, a change in their concentration in the water will affect the fermentation. Indirectly, a change in the fermentation will affect the dough characteristics, making it stronger or weaker.
Hard water will provide a fast fermentation and dough with a tendency to have an excess of strength while a soft water will generate a slower fermentation and dough with a tendency of lacking in strength.
The minerals in water provide food for the yeast, and therefore can benefit fermentation. However, if the water is excessively hard, there will be a tightening effect on the gluten, as well as a decrease in the fermentation rate (the minerals make water absorption more difficult for the proteins in the flour). On the other hand, if water is excessively soft, the lack of minerals will result in a dough that is sticky and slack.
Generally speaking, most water is not extreme in either direction, and if water is potable, it is suitable for bread baking.

A perfect understanding of ingredients functionality is very important to control the baking process and produce final products with a very consistent quality.
Sometimes, we don’t realize that without water, this precious ingredient, it will be impossible to produce bread. But when adequately used, water can be a determinant factor in obtaining desired dough and final product characteristics.

No comments:

Post a Comment