ROSEMARY ESSENTIAL OIL: CULTIVATION AND PRODUCTIONaromatic plantscultivation of medicinal plantsessential oilsfarmsteam distillation
A rustic and undemanding plant, Rosemary is certainly one of the most important and well known medicinal herb of our Mediterranean area. Widespread today in all countries with a temperate climate, where it is found both cultivated and natural, it is one of the easiest aromatic plants to cultivate, thanks to its great adaptability to the various types of soil and to the good resistance to low temperatures. Renowned and widely used in the kitchen, both fresh and dried, it is able to provide an essential oil with innumerable beneficial properties, both for the mind and for the body.
Rosemary, therefore, represents a medical plant, intended not only for drying, but also for the production of essential oil. How can a medium-sized farm produce Rosemary by itself for essential oil?
The purpose of this article is to provide an overview regarding this matter, starting from a cultivation hypothesis up to the distillation process.
The average duration of a crop is around 5-6 years, but under optimal conditions it can last up to 10 years.
Given the reduced germination of the seeds, the plant and the propagation of Rosemary generally occur by cuttings. Their preparation is relatively simple, you just need to cut, from the woody sprigs, sections (about 15 cm long) and bury them for half their length, in March-April or late summer. The cuttings must be kept in the nursery for about two months, to ensure a good rooting.
The planting pattern is generally done with a distance of 1 – 1.5 m between rows and of 0.5 m on row; for an optimal density of 2 plants/ m2.
The plant should be harvested in the correct time in which it produces the most active ingredients, between the end of spring and the beginning of summer. For the production of Rosemary essential oil, the period of full flowering is generally preferred.
At each cut, the yield of fresh crop for distillation is around 10-15 t/ha.
The yield on essential oil can go from 0.5 to 2%, for an average of about 0.8%.
Considering the production of fresh plant per hectare and its average yield, it is possible to obtain about 80 kg / ha of essential oil.
CULTIVATION AND PRODUCTION HYPOTHESES:
Assuming to grow about 800 square meters of Rosemary and considering an optimal system of 2 seedlings / m2, it will take at least 1600 plants to create the system.
If we consider the production of fresh plants per hectare; from a cultivation like this, during harvest time, at least 800 kg of fresh material can be obtained, which can be used for distillation.
If you have available a 125L capacity distiller, capable of processing 25 kg of fresh plant; it will be necessary to do at least 32 full-loaded distillations in order to process all the plant material.
If you do 4 distillations per day, in 8 days, all the work can be carried out, obtaining about 6.4 kg of essential oil (considering an average yield of 0.8%).
If you want to reduce your working days you could use a 250L distiller.
Proceeding by order, let’s see step by step all the phases of how the production of Rosemary essential oil takes place, through the use of a 125L distiller.
- Distiller with 125L capacity
- Rosemary stems and flowering tops, about 25 kg
- Running water
- Gas stove
Step 1 – gathering the plant material:
The first thing to do is to collect the plant material, the ideal technique is to mow the flowering tops about 30 cm from the ground, in order to collect only the most tender parts and encourage the vegetative growth of the plant.
It is good to remember that the Rosemary essential oil is contained in the glandular hairs present on the surface of the leaves, so it will not be necessary to chop the plant material for distillation. It is also useful to keep the stems intact and not use just the leaves. This will guarantee a better homogeneous passage of the steam and avoid the harmful “cork effect” due to packing the leaves too tightly during distillation.
Step 2 – load the distiller:
Once the vegetable material has been harvested it is important to proceed with the distillation in the shortest time possible, to avoid leaving the plant material accumulated for too long, and to trigger a harmful fermentation phenomena.
Mount the distiller and connect all the connecting pipes for the inlet and the outlet of the cooling water; you can proceed by inserting water into the bottom of the boiler, until it reaches the bottom grid and then load the plant material.
The plant material must be introduced into the boiler by distributing the stems evenly, creating layers. It is very important to press the material well, even by pressing it with your feet, without fear of squishing it too much; insisting especially near the walls of the distiller to avoid empty spaces from forming through which the steam could flow without coming into contact with all the leaves.
Once the load is filled, make sure that all the twigs are kept inside the boiler, positioning the upper grid on them, then close the distiller with its specific hinge.
At this point turn on the cooker to heat the water.
When the internal temperature reaches 50-60 degrees, the cooling water for the condensation circuit opens.
Step 3 – distillation:
At 50 ° C, the distiller’s temperature rises quite quickly and already around the 85 ° -90 ° C degrees the first droplets of distilled will be seen coming out.
At this point you just have to keep monitoring the temperature of the cooling water of the condenser, which must remain warm.
Leave the machine to distill until the level of the essential oil stops increasing inside the graduated cylinder.
Step 4 – bottling the essential oil:
Once the distillation has ended, it is necessary to separate the essential oil from the aromatic water, easily identifiable inside the graduated cylinder.
To facilitate the procedure it is possible to pour the contents from the distiller into a separating funnel, let it rest for a few minutes and gradually open the funnel tap, dripping the floral water first and then in a special amber bottle the Rosemary essential oil.
Learn more with the video:
Step 5 – maturation and conservation:
As with any freshly distilled essential oil, it is necessary that it ripens before you can fully enjoy its fragrance.
Regarding the conservation, the essential oil is a very delicate substance that can easily change and turn rancid, thus losing its natural scent and developing substances that can also be harmful. Therefore it is important to keep it always in dark glass bottles away from direct light and heat sources.
As we all know, the use of essential oils is done by drops. In fact, their use must be limited to small quantities as these substances are highly concentrated and rich in active molecules, many of which can also have toxic effects. Therefore, when using them it is necessary to do so carefully. Ask experts for advice.
And now all is left to do is to label all the bottles of Rosemary essential oil!
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