Methanol CH3OH aka wood alcohol. It is produced primarily by fermenting wood and other sources of cellulose like (fibers from fruit skin). Glucose, Sucrose, Fructose, and Maltose breaks down by yeast into ethanol C2H5OH. Another source of methanol is illegal distillation. Being lighter in molecular weight, methanol evaporates first in the moonshine still and is produced in the first distillate. Unscientific, crude distillation is banned because of frequent poisoning from unregulated stills making desi daru.

Methanol breaks down in the body forming formic acid (ant venom). Its build-up can cause liver failure, nerve damage (leading to blindness), and kidney/renal failure. 20-50ml of methanol is considered fatal. As per WHO, guidelines 6.70, the following test is recommended to test for dangerous levels of methanol in your homebrew.

Methanol Testing

Methanol aka wood alcohol is produced by fermenting wood, pectin, fibers from skins of the fruit etc. Fermenting fructose (fruits), glucose (grapes) ,and maltose (Barley and wheat) produces ethanol.
Prep Time5 mins
Active Time10 mins
Total Time15 mins
Course: Drinks
Keyword: blind alcohol, methanol, poison home brew
Yield: 1 test
Cost: 300

Equipment

  • test tubes
  • droppers

Materials

  • 1 ml Sulphuric Acid Diluted 1:1 (specific gravity 1.83)
  • 0.1 ml sodium dichromate (25gm/L) you can use potassium dichormate as well
  • 10 mg Chromotropic acid (Solid)

Instructions

  • Add 0.1 ml of potassium dichromate reagent to 1 ml of sample and allow to stand at room temperature for 5 minutes.
  • Add 0.1 ml of ethanol and about 10 mg of chromotropic acid and gently add sulfuric acid down the side of the tube so that it forms a separate layer at the bottom.
  • A violet colour at the junction of the two layers indicates the presence of methanol.
  • This test is accurate if Methanol levels are more than 50mg/L. Note Formaldehyde also gives a positive result in this test. (but again that is a poisionous chemical used for embalming and preserving specimens in biology labs)

Notes

Sulphuric acid is a dangerous reagent. So, please use adequate precautions in handling and storing chemicals. Also, this test is indicative at best. Please submit your samples to FSSAI lab for proper testing.

Buy Related Products

Video

Ankur

21 years of experience in Home Brewing and author of Arishtam (India's first homebrew Guide Book).

Leave a Reply