How yeast makes methanol

Home brewing has a very poor reputation in public. It is more than less prohibition moonshine distillers. People who make alcohol that turns you blind. While not a common truth today it is not without historical merit.

It is because of methanol that bootleggers have a poor reputation. There fermentation and distillation led to to the presence of too much methanol. Methanol causes blindness.

The key is too much methanol. No matter what you do there will be trace amounts present. Not enough to cause problems but enough to be detected with delicate tests.

The important thing is that it is made anyway. You don;y need to get the fermentation wrong or poorly distil the resulting wash.

When you do get these wrong the methanol concentration goes up. Distilling can remove some but not enough when done poorly.

The question is how does yeast make methanol. More so since it is so dangerous. Surely if methanol is bad for humans it would be bad for yeast and therefore not something yeast would make.

This contradiction is well understood in modern biology and microbiology.

The process involves pectin. A common part of many fruits, grains and more. Common ingredients for brewing. Therefore the resulting products include methanol.

The way you go from pectin to methanol is rather straightforward. The pectin is methylated. The methyl esterase breaks it free from the pectin. This leads to pectin and methanol.