http://www.digitaljournal.com/science/why-does-beer-taste-good/article/408885

Why does beer taste good?

Posted Oct 15, 2014 by Tim Sandle
One answer to this question could be “because it does,” but that doesn’t get to the heart of the matter. The answer is with yeast and the yeast aroma not only appeals to people, it has a particular attraction for fruit flies.
The Eden Project event brews its own craft beer. Digital Journal stopped for sample!
The Eden Project event brews its own craft beer. Digital Journal stopped for sample!
The yeasts used to produce beer produce chemicals that mimic the aroma of fruits. The mechanism at play is that the “fruit aroma” attracts flies, and these flies then transport the yeast cells to new environments. These same volatile compounds are also essential for the flavor of beverages such as beer and wine. Thus, the fly-attraction chemicals are also the same as the people-attraction. The most common fly to be attracted is the fruit fly (Drosophila melanogaster). The eye of the fruit fly is made up of 760 mini-eyes, making it one of the most complex organs in nature. The fly also has a highly developed sense of smell.
Yeast is essential in production of bread, beer and wine and people have been using different types of yeast for thousands of years to produce bread, beer and wine. A yeast is a type of fungus, a relatively complex organism.
The basis of the process is that yeasts consume sugars and convert them into carbon dioxide gas and alcohol. In bread, the gas causes leavening of the dough while the alcohol evaporates during baking. In beer and sparkling wines, both the alcohol and carbon dioxide gas are retained; whereas in wine the gas is allowed to escape. During this chemical process, yeasts produce several aroma compounds that are important for the taste, flavor and overall quality.
According to Lab Manager, scientists have now identified the genetic step that is key to the yeasts producing the flavour and which also attracts the flies. Research has shown that deleting a specific gene called ATF1 eliminates the attraction of flies to the yeast.
The researchers are of the opinion that the results could lead to the genetic development of new types of yeasts, which could be of benefit to the food industry. There is also a school of thought that thinks that understanding such mechanisms can assist with combating those types of yeasts that can cause human infections.
The research was carried out by scientists based at VIB, KU Leuven and NERF and the finding have been reported to the journal Cell Reports. The paper is called “The fungal aroma gene ATF1 promotes dispersal of yeast cells through insect vectors.”