Fermentation and ethanol questions, why does alcohol turn into vinegar?

Question

If you can help me with any of these, that would be great. Thanks.

During the fermentation process, why is it IMPOSSIBLE to get a soln with an Ethanol concentration of greater than 10-15% without using distillation?

Why is it possible to seperate and concentrate ethanol in the mixture during distillation?

WHY does alcohol turn into vinegar if it sits too long?

And why is ethanol dangerous or toxic to humans?

Answer 1

1. Yeasts ferment sugars in the solution to create carbon dioxide and alcohol. When the concentration of alcohol gets too high, it kills off or inactivates the yeast, meaning that you are limited to a low percentage of EtOH.

2. Since water and alcohol have different boiling points, you can fractionally distill the alcohol from the water. Ask me later about azeotropes.

3. The alcohol will oxidize if exposed to air and the correct bacteria. Just as yeast converted sugar to alcohol, certain acetobacteria will convert alcohol to acetic acid.

4. Ethanol is a depressant. Too much will slow down breathing and heart rate, causing unconsciousness or death.

Answer 2

Alcohol fermentation is the formation of alcohol from sugar. Yeast, whilst below anaerobic situations, convert glucose to pyruvic acid by using using the glycolysis pathways, then bypass one step farther, changing pyruvic acid into ethanol, ie Glucose-->2pyruvate--> 2acetaldehyde-->2EtOH So overview uncomplicated glycolysis for the right enzymes brewers yeast (Saccharomyces cerevisiae) is a fungus no longer a plant