21 May 2022
Leavening is a process through which a dough of flour swells due to the effect of carbon dioxide which is formed during the yeast fermentation process.
The fermentation of the yeast takes place when the sugars present in the dough are “annulled” with the consequent production of CO2, which remains inside it and causes it to swell.
This process is important because it has various benefits in the dough: the decomposition of the sugars increases its differentiability, creates a honeycomb structure which makes it lighter, reinforces the aromas during fermentation.
To obtain correct leavening, the following parameters must be controlled:The temperature; the right one for correct leavening to take place must be around 28°C.
The activity of the yeast is strongly influenced by the temperature: if, in fact, it is lower than 28°C, the action of the yeast is delayed, while, at a temperature higher than 28°C, the cells gradually begin to die , until the leavening activity is completely eliminated. (These values can however change according to the type of flour used)
Maintain the right level of humidity: the surface of the dough must maintain a certain level of humidity so as not to hinder the process of doubling the volume. The formation of a crust, even a thin one, would make leavening more difficult.Respect the leavening times, they depend on the type of yeast used, the ingredients and the methods of working the dough. Doughs made with white flour, for example, require less processing and leavening time, while those involving the use of oil or milk (for example, to prepare bread with oil or milk) require longer time.
Similarly, brewer’s yeast requires leavening which can take 1 or 2 hours, while mother yeast needs even longer times. In any case, leavening times should never be extended, even if the dough does not seem to grow properly: when the process is continued longer than necessary, the dough swells excessively and the gluten mesh begins to break, thus losing its ability to retain gases.
Standard tech designs and installs high quality systems in order to guarantee the best control over the aforementioned parameters, with capillary air distribution to guarantee the same thermo-hygrometric conditions for the product at every point of the room.
The humidity is created with low pressure steam generators which make the whole process sterile and guarantee the necessary saturation inside the room, but the steam is distributed through the air conditioning system and not directly inside the room, to avoid wetting the dough.