Pot distillation has been around for a very long time and the oldest methods involved simmering plants in liquid and collecting the liquid that cooked off them which I refer to as the distillate. Simple distillation apparatuses were discovered at both the Tepe Gawra (Mesopotamia 3500 BCE) the Mohenjo Daro (Indus Valley ca. 3000 BCE) excavation sites.
The Alexandrian perfumers’ guild (which was actually a group of early alchemists) was using simple alembics to distil floral essences beginning in the 1st century BCE. There is actually a very interesting story that alchemists sometimes tell about their discovery of a malleable glass that has been lost to time. In a 4th century manuscript written by Zosimus of Panapolis, he shares a pictures of their system. He is a good person to study if you are into alchemy and its history. In his manuscripts he tells each of his students they must obtain an alembic and instructs them on how to use them.
Another early illustration of a glass vase holding simmering liquid placed over a fire and covered with a conical top comes from a tablet found in the Keos, Crete excavation. The Arab word alembic is derived from the earlier Greek word ambix that described this vessel with its cone top. Aristotle wrote instructions on how to distil sea water using this method and Pliny and Dioscorides both wrote about using the process to extract mercury from the mineral cinnabar.
There’s no evidence that the ancients used distillation for making consumable alcohol. The Persians are generally given credit for inventing the alembics that were coil-cooled and consequently able to produce alcohol and that knowledge spread throughout their empire. It was mostly likely the Muslim Andalusians who passed the technology along Irish during trade. We don’t know exactly when, but we do know that the Irish were at it long before the rest of Western Europe. It was reported by the Anglo Saxons during the reign of King Alfred and the Irish were already being taxed by the English for making whiskey in 1276.
We have these directions from a French manuscript for making rosewater without an alembic from 1393.
Take a barber’s basin, stretch a kerchief over the mouth and fasten it, covering the basin completely like a drum. Put your roses on the kerchief and above them set the bottom of another basin containing hot cinders and live coals.[i]
Alternatively, the author says to do the same with two glass basins but to sit them in the sun and let its heat do the work. Several years back I posted another alternate method in this post.
The definitive Western European source on distillation was Liber de arte distillandi, written by Hieronymus Braunschweig in 1500 and translated into English by Laurens Andrewe in 1527. By this time, tradespeople involved in the sale of distilled products had taken the concept far beyond the small copper alembics as you can see here.
Women of the wealthy classes had still rooms in their homes and used the smaller alembics, however they were no longer exclusively copper. In his chapter on distillation in Delights for Ladies published in 1600, Hugh Plat mentions pewter, brass, copper, glass, and lead as materials for “limbecks.” Plat had preferences about which material he used for making each preparation. For example, he recommended copper for making cinnamon water but used pewter for Usquebath, Irish whiskey.
There’s a reason for this. Most of those old metals were not inert and would react with one substance or another. Copper reacts with acids and sulphur bonds. This can be good when using copper to remove sulfites from wine, but eventually acidity results in copper leaching into your food and copper is poisonous. This is why they line copper cookware with tin, stainless steel or silver (seriously who can afford silver-lined pans?) although jam pots are an exception to that rule because the high concentration of sugar in jams and jellies prevents that reaction.
I decided that I don’t want to have to think that hard and picked a small stainless-steel still that can just be used on the stove top. Stainless steel is a nice modern metal that is inert even if it doesn’t conduct heat as well as copper. I always place a stainless-steel rack on the bottom of my boiler to keep the plant material from touching the bottom and place the plant material in a stainless-steel steaming basket.
Some stills like mine come with a column that has holes in the bottom and attaches above a boiler. If yours does not have this and you feel strongly about using a column, you can improvise. I don’t really feel that the column set up offers many benefits when making distillates.
You can invert another basket on top of the rack and then set your plant basket on that to elevate the plant material above the water. I’ve done it both ways, but I sort of like having the strong decoction leftover to take baths in and make syrups. And it’s safe for me to do that because my boiler isn’t copper.
I’ve heard a few people say that you don’t want to boil the plant material because you don’t want it to cook. That’s ridiculous, because the steam is hotter than boiling water and degrades the material more quickly that boiling. That’s why steam distillation is faster.
- After you have placed the plant material in the basket this way, fill your boiler about half full of water. The exact amount is going to vary depending on the amount it holds. If you are not distilling something acidic, it helps to add just a bit of citric acid to your water because you want it to be slightly acidic. An ideal pH is somewhere between 5.5 and 6.
- Attach the condenser to your kettle. Connect the water lines to the condenser. The top line should then be connected to your faucet. The bottom line is your return line. If you hate wasting water like I do, you can collect the water in a bucket and use it for watering plants. Steve is investigating making me a recirculation system.
- Place your boiler on a heat source and turn it on.When the temperature on the boiler temperature probe reads around 180°F, turn on the cold water slowly until the water in the condenser are covered.
- Catch your distillate in small amounts in a non-reactive container with a tapered lid. I use labware made for this. You can see it the background of the picture below. If you can compare it to the picture above you can sort of see the evolution of lab equipment.
- Pour the distillate into a larger airtight container to settle. I am not going to lie to you. This is a time intensive project. I usually have a secondary thing going on that I can work on while it’s distilling.
- You should be able to hear when your water is getting low in the boiler. Then remove your still from the heat. When the liquid in the boiler cools, you can strain it and use it for baths or making syrups.
- Cap the container that you are consolidating your distillate in tightly to prevent evaporation. It will appear cloudy at first but as it cools the aromatic constituents will mostly be floating on top.
- After your still cools, clean the entire unit with vinegar and water. These aromatic constituents are very strong and can linger, so you want to be sure to thoroughly clean the unit.
- The essential oils will separate from the hydrosol as the solution cools and you can just use a dropper to siphon it off the top. I am not really into essential oils. I generally dilute them anyway so I just bottle my hydrosols in 12 oz beer bottles and keep them in a cool place.
- Most of you aren’t going to have bottling equipment so use dark-coloured, airtight, glass containers to bottle your hydrosols and essential oils. Clearly label them with the type of preparation and distillation date.
So I hope that helped answer some of the questions about the way I distill my holiday greenery, these days. If you go to my Instagram there are a couple of short videos in a post about it.
[i] Montigny, Guy. Le Ménagier de Paris. Translated by Hinson, Janet, 1393. http://www.daviddfriedman.com/Medieval/Cookbooks/Menagier/Menagier.html.  Plat, Hugh, Sir, 1552-1611? Delightes for Ladies, to Adorne Their Persons, Tables, Closets, and Distillatories. VVith, Bewties, Banquets, Perfumes and Waters. Read, Practise, and Censure.. Early English Books, 1475-1640 / 2300:10. At London, : Printed by Peter Short., [1600?]., 1600.