Debunking the Myth: Methanol and Safe Distillation

A common myth in the distilling community suggests that methanol can be removed from a distillation run simply by discarding the first few milliliters or ounces that come off the still. Allegedly, failure to do this could lead to severe consequences, including blindness or even death. However, science shows that methanol doesn’t behave this way in the distillation process, and the risk is often overstated. Here’s what you need to know to distill safely and understand the true facts about methanol. I encourage all readers to do your own research. In that regard, I have included source links at the end of this article to help you get started.

Methanol Facts and Toxicity

Methanol is toxic in large amounts; 30 ml (about 1 ounce) can cause blindness, and a larger dose can be fatal. The danger comes from methanol’s metabolites: when metabolized in the liver, methanol is converted by the enzyme alcohol dehydrogenase into formaldehyde, which in turn becomes formic acid. These toxic byproducts cause acidosis and organ damage. However, the amounts of methanol produced in typical home distilling are far below harmful levels, as we’ll see.

Methanol Levels by Fermentation Type:

Fruit-Based Ferments:

Fruit fermentation produces 250 mg of methanol per liter, which translates to about 1.1 ml per gallon of mash. Thus, distilling a 27-gallon batch of fruit-based mash would yield a methanol dose considered dangerous (30 ml).

Grain-Based Ferments:

• Grain-based ferments, which are commonly used in home distilling, yield much lower levels of methanol—around 300 mg per gallon or 0.38 ml per gallon. This means you’d need to distill nearly 79 gallons to reach a dangerous dose of methanol.

Sugar-Based Ferments: 

Fermentations using processed cane sugar produce virtually no methanol, making them a low-risk choice.

The most common instances of methanol poisoning are linked to ingesting industrial products like windshield washer fluid, often in attempts of self-harm. This is a stark contrast to home-distilled spirits, where methanol levels are significantly lower. If home-distilled products were inherently dangerous, they would certainly contribute more cases of methanol poisoning than suicide by washer fluid.

Can Methanol Be “Boiled Off” at the Beginning of Distillation?

Methanol has a boiling point of 148°F (64.7°C), lower than that of ethanol (173.1°F/78.37°C), which may imply that methanol boils off first. However, methanol’s behavior in a still is more complex, thanks to hydrogen bonding and the dynamics of vapor-liquid interactions during distillation. Where methanol is released during your run depends heavily on what type of still you're using.

Pot Still Distillation:

Methanol tends to come out mostly in the tails, with smaller amounts spread across the heads and hearts.

Column Still Distillation:

In a column still with multiple bubble plates, methanol is generally concentrated in the heads but can also be spread across the hearts and tails sections. Using a deflagmator (a type of forced reflux system), most methanol can be compressed into the heads, yet traces still remain throughout the hearts and tails.

Even if methanol concentrates mostly in the heads, the heads account for around 30% of the run, meaning that simply discarding a few ounces at the beginning does not remove all methanol. This dispersion is why separating a small portion early on is not an effective way to eliminate methanol.

It is also worth noting here that some distillers will do what they call a "blue flame test" where they take a small sample of their distillate and light it on fire to check the color of the flame. It is believed that if the flame is completely blue then there is no methanol present. This is false. Methanol also burns with a pale blue flame similar to ethanol.

Reducing Methanol Production in Your Ferments

Methanol is a byproduct of fermentation of pectin-rich materials, primarily in fruit mashes. However, methanol levels can be reduced through a few practical steps:

Pectic Enzymes reduce the production of methanol:

Adding pectic enzymes before fermentation can reduce methanol production by 40-70%, making your final distillate much safer.

Timely Distillation:

 Methanol can continue forming after fermentation is complete, so it’s best to distill shortly after fermentation to limit additional methanol production.

Conclusion: Distill with Knowledge, Not Fear

Methanol can indeed be dangerous in high doses, but typical home distilling does not produce methanol concentrations at hazardous levels. Understanding the science behind methanol production and its behavior in distillation allows distillers to approach their craft with confidence. Rather than relying on outdated myths, home distillers should focus on good practices—using the right ingredients, timely distillation, and careful separation of heads, hearts, and tails.

By approaching distillation with knowledge and care, you can ensure your craft is safe, enjoyable, and free from the specter of methanol toxicity.

Source material links used for this article:

Still Behind The Bench 

National Library for Medicine

The Methanol Institute