When moisture is Torture!
In this column, we share with you regularly our experience in major application areas where usage of dehumidification is both extensive and essential.
Yeast Drying
Just imagine life without yeast . . . where would we be without the discovery of yeast? Our life would be void of many of our day-today products, like freshly puffed bread, refreshing beer, wine and other alcohol products, which are the gifts of yeast to us.
Yeast is a living organism that feeds on natural sugars, producing carbon dioxide to leaven bread. Yeast is also responsible for fermentation and is used to make wine as well as beer.
History
It is believed that yeast is the man’s oldest industrial micro-organism. Without knowing its role or its existence, man has used yeast even before the development of a written language.
Yeast production is truly an age-old technique and process. The story of yeast is as old as the story of bread. For centuries, yeast has been associated with bread making as a fermenting agent. The origin of bread, though obscure, dates back to the Stone Age, while raised bread developed around 4000 B.C. Traces of yeast were discovered in beer jars and beer breads were used as offerings in the ban tombs in 2000 B.C. Fermentation, originally a matter of chance contamination of airborne yeast, was promoted by using a piece of old dough. To this day, this is the method the most well-known bakers choose.
Today, yeast-making has become a specialized profession. Yeast is now commonly available in packets and foil sachets in the supermarket. However, there is nothing new in the function of a raising agent for imparting that special light texture to the bread we eat. Yeast is made up of living cells with the ability to change sugar and carbon dioxide.
Yeast Making
Drying of yeast an intricate process, requiring cold dry air to produce quality yeast without destroying the organism. The quality of air required for drying of yeast has to be controlled and moisture content kept between 10-14 grains/ib (1.6 gm/kg-2gm/kg) or the dewpoint of air must be in the region of 12-18°F. (-11 to 7°C).
Yeast making is truly an art and science. It involves growing the organism in suitable media. The most popular yeast for winemaking, baking and brewing since ancient times is Saccharomyces cerevisiae. Saccharomyces cerevisiae is the microorganism which is prepared in the laboratory as the seed yeast.
The crop is harvested when a sufficient crop of cells has appeared. This is then transferred into a clear mineral salt-sugar solution, used as the medium, where fermentation occurs. The temperature is kept constant for rapid growth to take place. The yeast cells are then separated from the fluid in which they have grown by a filtration process. The yeast cells are mixed with starch cells and pressed into large cakes. Fresh yeast can survive only for a few weeks at controlled temperature of 4°C. Hence, it needs to be stored in specially constructed cold stores. On the other hand, dry active yeast can be kept for two to three years without any loss of properties.
Bry-Air provides the right solution
Bry-Air dehumidifiers maintain the required stringent conditions in the drying area during the manufacturing of yeast. The manufacturing yeast, as we have seen involves low temperature drying. Though elevated temperature ensures faster drying, it can affect the product quality. Bry-Air equipment specializes in such applications. In conjunction with air-conditioning plants, very dry air at low temperatures can be supplied for the product drying applications since they are capable of maintaining RH as low as 1% or even lower at a constant level, regardless of ambient conditions.
