The initial setup uses a reaction engineering interface to simulate the fermentation, assuming a fully mixed type. Another setting analyzes the fermentation of spherical grooves in geometries, taking into account mass transfer, heat transfer and natural convection. These models are concentrated in the selection of yeast strains that are fermented at temperatures close to 12 degrees Celsius, which is ideal for brewing beers.
The mechanism of the fermentation process depends on the yeast concentration, which is modeled as free species, and the reaction rate. The yield factor is used as a means of calculating the product concentration and correcting the level of alcohol production. In this example, gaseous and dissolved carbon dioxide is also calculated.
Contains water as solvent because the wort mixture has similar thermal properties. Has a temperature below the initial temperature of the tank, and a cooling medium is used during the fermentation process.
Over time, all the sugar will be reduced, while the alcohol content is greater than 5%. What does this taste for beer? Because it will contain a lot of aldehyde, so the taste of beer may be poor. In order to give it a better taste, one option is to extend the fermentation time. The aldehyde content will eventually exceed the maximum and begin to decrease. If you want to lower the aldehyde content faster, another way is to increase the initial yeast concentration.
Spherical grooves are common reactors that produce fermentations. Some of the advantages of this tank design are that it allows the yeast to be easily separated from the top or bottom liquid of the tank and provide better temperature control. Although tanks are sometimes simply placed in a cooling environment, most of today's brewing equipment includes a built-in cooling jacket.
By coupling the three interfaces - the propagation of the dilution species interface, the laminar flow interface and the heat transfer in the fluid interface - we treat natural convection as the only source of mixing. The temperature is assumed to be the only property that affects the density of the mixture, and the source term is added to the laminar flow interface to simulate the mixture.
When comparing the cooling efficiency between the two models, the spherical reactor appears at the top, keeping the temperature close to 12 ° C. Implementing the same process conditions in a fully mixed model will require an increase in the cooling rate capacity by at least one order of magnitude. In order to obtain a product of the same nature as the fully mixed model, the fermentation within the spherical groove needs to extend over 200 hours. Eventually get a higher quality beer.