Distillation Hazards
Distillation is more hazardous than wine or beer making because you are producing a product that has flammability similar to gasoline. If you wouldn’t do it with gasoline, don’t do it with distilled alcohol. Having said that, with the right precautions, safe handling of high-proof alcohol is easy and shouldn’t prevent you from pursuing your passion for distilled spirits.
I have spent over 8 years working in a refinery and chemical plants as well as an additional 7 years in a biomedical research facility, so I’ve spent lots of time reviewing safety procedures. My experience working at an oil and gas research facility has given me some excellent insight into handling flammable materials safely, and as you go through this module I’ll give you everything you need to know to handle high-proof alcohol safely.
The key issue at a distillery is the obvious fire hazard. Alcohol and heat produce a vapour that when mixed with air creates the perfect conditions for a fire or worse an explosion. The trick is not to allow the three (alcohol, air and heat) to mix.
The key to dealing with any common fire hazard is to remove fuel (alcohol), oxygen (air) or heat. If one of those is removed, the fire will cease. But we’ll talk about this in more detail shortly.
Flash Point vs Auto Ignition
There is a lot of confusion around these two terms and they are important to understand, so let’s clear it up. The flashpoint of a liquid is the temperature that vapours above the liquid will ignite when exposed to an open flame or spark. With ethanol you need to know this, the flashpoint, even mixed with water at 40% abv, is close to room temperature, high ABV ethanol (80% and up) is around 15°C (59°F), and this is why bartenders can easily make flaming shots and Spanish Coffee. Flashpoint requires an open flame or a spark to ignite the vapours.
Auto-ignition is the temperature at which the liquid will automatically combust in the presence of air (oxygen) and generate a fire or explosion. An example would be accidentally spilling ethanol onto a heating element, which would result in an explosive fireball. The temperature required is 365 °C (689 °F) which is relatively high, but electric heating elements can easily surpass this temperature so if you are using these, be very cautious about keeping the element submerged in liquid.
For reference, gasoline auto ignites at 247–280 °C (477–536 °F), methanol at 440°C and iso-propanol at 399°C.
Static Discharge
Whenever you are dealing with high proof spirits, make sure everything is properly ground to avoid static buildup and potentially causing a spark that could ignite the ethanol vapours. This is more of an issue on dry winter days, but you should always use grounding straps/cables when transferring ethanol between two things (tanks, buckets, still, etc) in the open air.
Personal Protective Equipment (PPE)
Flame resistant clothing, avoid synthetic fabrics as they will melt. Denim and cotton are good choices and if you want to be pro-level Nomex clothing is excellent. At one time you could only buy Nomex as coveralls but now they’ve taken some fashion advice and made shirts and pants available.
When it comes to other equipment, for example collection and storage of ethanol, use appropriate containers. Metal, like stainless steel and copper are excellent, and some plastics like LDPE or HDPE are appropriate for storing high proof ethanol, but they may not be as durable when collecting hot spirit though they are fine at room temperature.
Glass is inert but can break easily so I don’t recommend using glass fermenters as primary storage vessels. Small glass is fine because it limits the amount of ethanol that can be released if broken, but take this to mean you should have a wall of mason jars on a rickety shelf.
Ventilation
One of the best things you can do when you are fermenting or distilling is to have good ventilation. Alcohol and carbon dioxide from fermenters can build up due to poor airflow which can have negative health effects. The most common ones are feeling tired, and being less than sharp mentally. Lower than normal oxygen levels can cause this, as well as the low levels of alcohol.
GRAS Substances (SCOGS) Database
Whenever you make something that people are going to consume, you must be sure that your ingredients are safe. For example, if you decide to make a gin from a botanical you grow at your distillery, you should first check to see if it is safe for human consumption. The FDA has a searchable database that can help and is free to use for anyone around the world. https://www.fda.gov/food/generally-recognized-safe-gras/gras-substances-scogs-databasewww.cfsanappsexternal.fda.gov/scripts/fdcc/?cat=FoodIngredientsPackaging&type=basic
If you can’t find the herb, spice, grain, etc. in the FDA database, you can check with the Agriculture Department as the GRAS database tends to deal with food additives and is not comprehensive which means it doesn’t include things like lettuce or kale. I’m sure somewhere has though about a kale flavour spirit. Anyway, when it doubt, check it out first.