Q: Anthony, I want to explain to readers that beer and bread have similar ingredients, but why you get a buzz from drinking beer and not from eating bread.
A: There are four ingredients in traditional beer: water, barley, yeast, and hops. Bread is made from the first three of these ingredients but doesn't have hops, which are added to beer as a preservative and bittering agent to balance the sweetness of the barley. Beer is often referred to as "liquid bread" because of this similarity in ingredients, and one of the theories on how we invented beer is that people were collecting barley to make bread and left it out in the rain, thus adding more water than you'd find in bread as well as yeast that floated into the mixture from the air.
Most people think yeast breaks the sugars in barley down into ethyl alcohol and carbon dioxide, but that's actually a secondary reaction. Initially, yeast breaks sugar down into pyruvate, which is composed of three carbon atoms. In the presence of air (as in bread) the yeast is then able to completely combine these carbon atoms with oxygen atoms and form CO2. Without air (like in the bottom of a barrel of fermenting beer) the yeast can't combine all of the carbon with oxygen, and so the pyruvate is converted into both ethanol and CO2. Thus beer ends up alcoholic and bubbly, while bread dough just ends up bubbly. Hope this helps!