The distillation process

At the heart of our work, is the extraction of the essential oils from the plant material we pick. It has taken us a lot of studying, experimenting and feedback from our clients to perfect it. We are always fine tuning it, to reach the highest level of quality possible.

Steam distillation

Our distillers implement the method of steam distillation. The basic principle is that the biomass is not submersed in water and hot steam at 100oC passes through it. The essential oils and other water soluble components of the plant reside inside various biological structures located on or inside the leaves, flowers, stems or seeds. The hot steam opens up these structures releasing and carrying away the chemical compounds. The mix is then channeled to the condenser which cools it down, turning it into liquid again. The output flows into a glass separator which takes advantage of the fact that the oily compounds have a lower specific gravity than the water and water soluble compounds. The oily compounds concentrate on the top part of the separator forming what we call the essential oil and the water with the water soluble compounds exit through the exit pipe of the separator, which constitutes the hydrosol.

Preparing the equipment

All equipment used in the distillation must be super clean before starting. This includes all parts of the distiller, the separators and any receptors used. We use dish soap for all of them and rinse everything to the point that there is not even a suspicion of soap left in any crevice. For the distiller we use a power washer to that end.

Then everything is assembled into their operating positions.

Loading the herbs carefully

This step of the process can greatly determine the outcome of the distillation. A distiller that is wrongly loaded can be the reason to produce just water, burn the herbs and the essential oil or in extreme situations, cause the distiller chamber to rupture and blow. During our early stages, we experienced all of these but the last!

The herbs have to be loaded in the biomass chamber in a way that allows the steam to circulate but at the same time provides a small resistance to it so it is forced to penetrate the plant material and extract the substances we need. In order to achieve that, a lot of experimenting is necessary to find the completely unique method of loading the distiller for each herb. A general rule is that any bunches that formed while picking must be broken and the herb must enter in a chaotic-but-uniform way.

Compression must be applied while loading, but not too much and not too little. Every particular distiller has its own “know hows” and for each of our distillers the rules are different, even for the same herb.

The distiller must be filled to at least two thirds of its capacity to run, even though we make sure that it is almost always 100% full for perfect operation.


Once everything is in, we close up, open the distillation water valve and light the propane burner. Now is the time for patience. For the first half an hour the distillation water is heated up to boiling temperature to produce steam. Another half an hour to an hour for the first steam to penetrate through the whole of the biomass and start heading towards the condenser. We then turn on the cooling water. We should note here that the exit of the cooling water is connected to a drop system watering network throughout our land, so it does not go to waste.

Once the steam reaches the condenser unit, it cools down, condenses and magic happens. The first drops of oil appear in the separator. As of this point the distillation will last between 2 to 20 hours, depending on the herb we are distilling. During this time the output of oil will fluctuate and accumulate in the separator.

A lot of things are happening inside the distillation chamber and close monitoring and adjustments are necessary throughout the duration of the distillation. For example, the biomass may get soggy and start to collapse having to be countered by an increase in steam pressure. Or channels may open in the biomass cancelling the penetration of steam through it, having to be countered by various methods and a number of other situations. As Murphy’s law says: “Everything that can go wrong, will”. Knowing how to avoid and deal with each situation when needed is what makes our experience. No matter how many books we read, or workshops we attended, the main way of gaining that experience has been one: Trial and Error!

Our senses, listening to the sounds of the distiller, smelling the output, feeling the temperatures on its parts, observing the color and viscosity of the essential oil that is coming out, are our inputs to understand what is happening, to evaluate the situation and to judge if an action should be taken and what that should that be. If necessary we may change the distillation speed by adjusting the fire intensity, shake the distiller or just be patient. Waiting patiently and observing can be the solution to some of the problems.

Ending the distillation

One of the secrets of making high quality essential oils is knowing the minimum distillation duration for each of the herbs we distill. For example, we may get 100ml of oil during 3 hours of distillation and 5ml more if we let it run one hour more. One could argue that its not worth the time, energy and water spent for one more hour to get just 5% more of essential oil. This is wrong thinking though, because some of the plant structures that hold compounds of the essential oil are hidden deeper into the plant material and the compounds they hold can be different from the rest. This means that until we get those compounds as well we do not have the complete profile of the essential oil. Without the complete profile a therapist cannot rely on it for its full therapeutic force.

So, the distillation must run for at least the minimum amount of time recommended for the herb that is being distilled. Of course, if there is more oil coming out after that, we can keep on going, but we may cut the productive output of the hydrosol, since it may become weak. We use our noses to determine that.

One we judge it is time to stop it, we put out the propane burner and turn off the cooling water and take the separator in the lab for immediate filtering and storing.

Disposing of the biomass

The biomass we distilled, depleted of its essence, is still excellent organic food for plants. Once it has cooled down, we unload it from the distiller onto a wheelbarrow and dump it on top of our big compost heap. Every season we draw from the heap’s bottom excellent organic fertilizer for our vegetable garden!