Expert: George Maxwell - 10/4/2007

Question
What is the main difference between iso-propyl alcohol and the alcohol in beer?

Answer
Hi, and thanks for your question.

Chemically, isopropyl alcohol and the alcohol in beer (ethanol) are similar, but not identical: they both contain carbon, hydrogen and oxygen atoms, but ethanol contains them in the ratio C2H5OH, wheras isopropyl contains them in the ratio C3H8O.

This difference is small in physical terms: both the alcohols are colourless, flammable liquids and they react similarly. Biologicaly, however, they're very different: ethanol is a mildly harmful liquid (hence it's just about safe in beer etc), but isopropyl is very toxic.

Hope this helps,
thank you.