So how do I distill lavender essential oil? Have you ever steamed vegetables before? Well if you have, chances are you can distill lavender to extract its essential oils.
Much like baking a beautiful cake, there is a tendency to look at the finished product and think about the beauty of the finished product and ignore the science behind what happened in the oven. I often hear my fellow lavender farmers and distillers refer to essential oil distillation as an art. While there is some creativity involved in the process, distillation must fall within certain parameters to get an ideal product. This is why I would argue distillation is more of a science. Also the distiller has little control over the chemical processes inside the pot once distillation has started. Thus knowing the science is half the battle! So, here we go.
Lavender essential oil distillation happens through a process called steam distillation or sometimes wet steam distillation. Either way the process is very similar. First, take a pot or kettle and you put a steam tray an inch or two above the bottom of the kettle (depending on the size of the still this could be many inches on a larger still). For our 60L still we sit our steam tray on 1 inch pieces of copper pipe. For our 300L still our steam stray sits about a 10 inches from the bottom of the still. Next, fill the kettle with water up to the steam tray line. All of the lavender will now sit on top of this steam tray, the tray will keep the lavender from touching the bottom of the pot and burning.
Prior to setting up our still I will have cut the variety of lavender I am going to distill. For a 60L still I will need about 20-25 lbs of freshly cut lavender. For our 300L still I will need 100-120 lbs of lavender. 20-25 lbs of fresh lavender is anywhere from 6-12 full lavender plants depending on the variety, age, and health of the plant. We cut out lavender short to avoid packing in too much stem . We also cut our lavender much later in the year when the lavender is overly ripe and fully flowered. When the plant is fully flowered is when it has the most amount essential oil. We pack the lavender in the kettle of the still on top of the steaming tray trying to avoid pockets of air between the lavender. It is ok to pack the still tight, don’t worry about over stuffing the still. We fill the lavender all the way to the top of the pot. Once we have the pot filled up we put the lid of the kettle on and connect the swan neck from the pot to the condenser and turn the heat on under the kettle.
Ok I promise here is where it gets exciting. Just like steaming vegetables the whole point of the distilling process now is to boil water and turn the water in the bottom of our kettle from a liquid to a gas (steam) so it can rise and pass through our kettle that is now stuffed with lavender. As the steam passes through the lavender the pressure inside the sealed kettle along with the high temperature of the steam causes the bud of the lavender (the calyx) to release its essential oils.
Did you know? The bud of the lavender not the actual flower is where most of the oil is held in lavender. .
The smaller pot that the large kettle connects to is called the condenser. The condenser is where the the pipe holding the steam which contains the water and oil travels to cool off. The pipe coils very gradually down the condenser as you see above. The condenser is filled with cool water to cool the pipe containing the steam. This allows the steam to go from its gas state back to a liquid state. The water around the condenser coil heats up during this process so we have the hot water exit out of valve on the top of the condenser. The hot water is replaced by cold water that enters the bottom of the condenser pot. This allows the condenser to cool the steam gradually. After it cools down and turns back to liquid it drips out the end of the condenser into our separatory funnel.
This may seem straight forward but I address it because it is commonly misunderstood. When the oil and water come out of the condenser into the separatory funnel they separate. As most people know oil and water don’t mix, so this is nothing special, but what I often hear is oil floats on water because water is heavier, This is false. There are two reasons why the oil floats on the water. First, the dipole-dipole bond between the water molecules is much stronger than any of the reactions happening between the oil and water so the oil will not pull the water bonds apart. Second is water is more dense not heavier than oil so the water sinks to the bottom. Additionally, the essential oil, like all oils, is hydrophobic.
Yields depend on the variety. The species Lavandula X Intermedia, lavindins, produce the most oil. Grosso which is the most common variety of lavender, is one of the highest oil producers. We get about 225-300 ml of oil per batch for Grosso from 20-25 lbs in a 60L still. The species Lavandula Angustifolia sometimes referred to as English lavender is a low producer of oil. Some varieties produce more than others but typically we get 30-120 ml depending on the variety of Angustifolias. English lavenders produce the most desirable essential oil. Lavandins have more camphor in their oil. Camphor is the same scent you find in vicks vapor rub. Don’t let this turn you off from Grosso oil however, many people still really enjoy Grosso’s scent because it is the most common scent of lavender. Grosso is the smell most people recognize as lavender. The English varieties have a much sweeter smell and are more desired in the aromatherapy arena.
The lavender water that comes out with the oil is now referred to as Hydrosol. If you put the correct amount of water in your still (not too much so you don’t water down the hydrosol) you will get another desirable product, lavender hydrosol. You can learn more about hydrosol here. Hydrosol is used for removing makeup, body sprays, deodorants, linen sprays etc. We use it in our linen spray that we sell here on our farm.
Why do we use Copper for distilling? As Ron Burgundy would say, It’s Science. We use copper because it allows us to give you a freshly distilled superior smelling oil. A scent in oil no one really cares for is sulfur. You know that rotten egg or burnt match smell… Yeah we don’t like it either. We want to make sure the sulfur smell is taken out of the essential oils, because sulfur is in most plants in small amounts. Fortunately for us Copper molecules have a +2 ionic charge and Sulfate molecules have a -2 ionic charge, so the two elements really like each other and make a beautiful teal green powder called copper sulfate. You can see the greenish teal marks on the side and bottom of my still. It is easily washed away with a little water.
A couple of notes We cut our lavender for distilling when the lavender buds have fully flowered which is when the lavender buds have the most oil. We cut the lavender with short stems to get as much of the lavender flower heads in the kettle as possible We distill all of our lavender in our 300 Liter or 60L copper still made by Copper Brothers.