Beer, as all alcoholic drinks, is made by fermentation caused by bacteria feeding on the yeast cells, then defecating. In Bavaria, beer is not an alcoholic drink.
Modern breathalyzers work on a clever electrochemical principle.
The subject's breath is passed over a platinum electrode, which causes the alcohol to bind with oxygen, forming acetic acid. In the process it loses two electrons, a process that sets up a current in a wire connected to the electrode. The higher the concentration of alcohol in the breath, the greater the electrical current, which can be read by a simple meter to indicate intoxication levels. It has been medically proven that alcohol, does in fact, kill brain cells. However, the use of marijuana, has also been medically proven to only numb the brain cells.