Laboratory Verdict: Methanol!

12 January 2023


Today, we want to talk about methanol. What is it? How is it made? What are the regulations and norms on methanol? These are all important questions that deserve answers. This iStill Blog post aims to provide the answers.

After learning about methanol, we'll look at the methanol content levels of Jim Beam, MacAllan, and iStill whisky. First, we'll make a prediction, based on Odin's Holy Trinity of Distillation. Secondly, we'll share the scores of each and every whisky. Finally, we'll follow up with some conclusions and implications for craft distillers.

What is methanol?

Methanol is a low boiling point alcohol that is very toxic. It attacks the nerve system directly, and the eye nerve specifically. Higher amounts of methanol consumption can cause blindness. Even higher amounts of methanol can cause death.

As it is very toxic and potentially lethal, it is important to find out how methanol is formed and how it is regulated. If we understand formation, we can control formation. If we understand the norms and regulations, we'll learn what to aim for.

How is methanol made?

Methanol is made by yeast that is stressed out a bit. It is a byproduct of fermentation. Especially hotter fermentations, can create the environment for yeast to produce methanol. Theoretically, this makes perfect sense, as methanol is a low boiling point alcohol. Low bp alcohols are generally the result of elevated fermentation temperatures.

Methanol is also made from wood sugars. If wood particles, or pectins, are present during fermentation, the sugars in the wood particles will be turned into equal amounts of ethanol and methanol. The more wood-like organics are present, during fermentation, the more methanol will be formed.

Stone fruits have a lot of pectins and fruit brandies are therefore usually high on methanol content. Grains have much, much lower amounts of pectins, so we'd expect the whiskies, that we'll test later on, to score better.

Methanol: norms and regulations

The European Union regulates methanol for brandies, grappa's, and fruit brandies. And on GNS, vodka, and London Dry Gin. Not on whisky, though. But the Australians and New Zealanders do, so we'll take their numbers as the norm. Craft distillers and iStill customers can be found around the globe, not just in the EU.

Here you go. Maximum methanol count, in parts per million, for specific spirit categories:

  • London Dry Gin: 50 ppm (EU-norms);
  • Vodka: 100 ppm (EU-norms);
  • GNS: 300 ppm (EU-norms);
  • Whisky: 400 ppm (AS/NZS-norms);
  • Brandy: 2,000 ppm (EU-norms);
  • Fruit brandy: 10,000 ppm (EU-norms).

For more information on norms and regulations, also from North America and China, please see:


For now, we'll continue to work with the Jim Beam, MacAllan, and iStill whisky samples we have been using in previous posts as well. Since whisky doesn't contain a lot of woody material, in the making process, we expect very moderate methanol levels in general. But diving into the specific ways in which the three grain spirits are made, we can at least make a few predictions:

We expect the Jim Beam to be relatively high on methanol, since they ferment on the grain and use outdated, bubble-cap technology. On-the-grain ferments introduce slightly more woody materials to the yeast than off-the-grain fermentations. And as bubble-cap trays are a technology from the 1870's, not a whole lot of control is achieved over the distillate, during the run.

The iStill whisky is also fermented on the grain, for 5 days instead of Jim Beam's 3 day fermentation cycle, which should result in slightly higher methanol levels. Yet, we expect the methanol levels to be lower than in the Jim Beam, because iStill's modern distillation technology offers more control and better separation power.

The MacAllan is distilled off-the-grain, and should therefore have low methanol numbers. Also, the long maturation time, that the MacAllan has seen, will allow more of the methanol to have recombined with other substances into new and different molecules.

MacAllan and Jim Beam both run uncontrolled fermentations. There is no temperature control. And as fermentation is a heat-generating process, this puts strain on the yeast and will create relatively (see next paragraph) more methanol. iStill fermentations are temperature controlled, so should perform better, but in order to create a big front-end, we also like to ferment at higher temperatures, like 28c continuously, which may mitigate the differences with the cooler starting, yet hotter ending fermentations of both Jim Beam and MacAllan.

In general, we expect all three whiskies to score significantly below the AS/NZS-norms and regulations of 400 ppm. Simply because there isn't a whole lot of pectins and wood for the yeast to make methanol from. The MacAllan, due to the long maturation time and off-the-grain fermentation is expected to score a bit lower. The Jim Beam, with its big, non temperature controlled ferments, might see slightly higher outcomes.

Methanol content (measured in ppm/liter):

All whiskies are far below the 400 ppm norm. In fact, all whiskies are even below the EU-norm for vodka! As predicted, Jim Beam, because of the non-controlled, on-the-grain fermentation, combined with an old distillation technology, scores the highest numbers. The iStill whisky, even though it is fermented on the grain and for five instead of just three days, scores better, because of its modern technology that gives the distiller more output control. A lower fermentation temperature of 24c instead of 28c would probably have brought the numbers down to below 50. The MacAllan scores slightly better than the iStill whisky, due to the much longer maturation period (12 vs. 3 1/2 years) and of-the-grain fermentation protocols.

Conclusions and implications for craft distillers

  • Methanol contamination in whiskies seems to be well below the available regulatory norms;
  • Odin's Holy Trinity of Distillation perfectly predicts the differences between the whiskies, minor though they are;
  • On vs. off the grain distillation, as well as fermentation temperature & control, slightly impact methanol formation;
  • It would be interesting to see how vodka's and London Dry Gins perform, given the more restrictive norms;
  • It would be interesting to investigate how fruit brandies perform, given the very lenient norms.

Managing and meeting methanol norms and regulations is important. As a craft distiller you need to prove you comply. If you want to have your spirits tested for methanol content, the iStill Laboratory can help. Please reach out to if you want to order our tests.

Methanol ...


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