Lemon Verbena Distillation (Jan 2014)

Aloysia triphlla (Lemon verbena) in flower

Lemon verbena (Lippia citriodora) or Aloysia triphylla is a precious essential oil which has a low yield and is quite hard to come by the genuine oil. Details as to its origins and habitat can be found here on Wikipedia.  It is believed many so called lemon verbena oils on the market are heavily adulterated with lemon thyme, Litsea cubeba (May chang) or synthetic citral. Previously I have used lemon verbena hydrosol my friend produced on his lavender farm (, with only a tiny amount of oil obtained. Most of his lemon verbena leaves are destined to be dried and sold as a herbal tea. On the 29 December 2013 I was able to take part in the harvest and distillation of his organic lemon verbena. The key difference this year is that it is the flowers and leaves which are being distilled, not just the leaves. Leaf only essential oil can produce a high (up to 35% citral) content which, being an aldehyde may irritate the skin.It is also believed to be a photosenstiser.(1). However the flower distillate is believed to have a lower citral content, and therefore be less of a sensitisation risk (2).

Lemon verbena (Aloysia triphylla) oil contains at least 40-69 different constituents, with geographacial variations apparent; oil from Argentina had >36% myrcenone; whereas Turkish distilled oil had quite a differnt chemical profile; and Moroccan oil contains 1,8 cineole along with other expected constituents. Other research identifed that Chilean oil has seasonal variations in the citral conten here.
Here in NZ, no such analysis has been undertaken and the oil is produced in such limited quantities that any cost of having a GLC analysis done would be prohibitively expensive. This distillation is as much about the essential oil produced as the hydrosol which has a high percentage of volatile componets left in after the disitllation as only the best is extracted for the essential oil. The E.O. is antiviral (diffused) and a relaxant. If it is going to be used on the skin i would recommend patch testing first for sensitivity and using in less than 0.2%, however do not the potential for phototoxicty already mentioned.
Lemon verbena Hydrosol Facts (Ph 5.2-5.5) which is considered similar to the acid mantle of the skin and therefore will be valuable as a skin clarifying agent. It is believed to be anti inflammatory and has none of the irritant concerns of the essential oil. 
Internally the hydrosol can be used for intestinal and pelvic cramps and as a tea is a great stress reliever, working on the autonomic nervous system. Lemon verbena hydrosol is also very resilient and should last at least 18 months (3). I have some stored in the fridge now for 3 years and no sign of going off. 
Harvest Day!
The lemon verbena trees are tucked about on the organic farm as well as being in a couple of neat rows. The trees are around 5-6 feet in height and harvesting is done by hand with sharp sterilized secateurs. Thomas had already done a large part of the work the night before to beat the weather, and we (my husband and I) spent about 90 minutes finishing off a dozen or so trees.The weather was perfect- low cloud and cool with the rain holding off. This is not a job for the heat of summer which will be with us in a couple of weeks when the lavender will be harvested.

Showing where the flower and top leaves were hand cut for harvesting. Bulk of leaves left on plant for later harvesting for tea and possibly another distillation
The main row being harvested
About 15 -20 mins work
The still pot filled with fresh harvested flowers picked today and the night before. Weight of material approx 34 kg
Buckets of hydrosol ready to go into cool dark storage
Steam generator

Clock watching- the steam entered the still at 0930 am and by 0937 the first drops of EO and hydrosol were coming out of the condenser

View inside the separator- at this point the oil is mixed with the hydrosol prior to separation (needs to fill up a bit more). Yiu can see the oil molecules swimming on top. The aroma at this point is just divine!

This is the oil/hydrosol mix filling up the separator and spilling over at the peak point of production-exciting!
The temperature of the condenser is kept at a constant 45 degrees Celsius and is adjusted through the control of cold water entering the condenser. 

At the end the oil is separated off and frozen to remove any remaining hydrosol.

The technical Stuff:

  • Still charge 34 kg fresh plant material (flowers and leaves) -minimal branches
  • Total distillation time 90 mins
  • Essential oil Yield 90-100 ml (most of the oil reabsorbed into the hydrosol)
  • Hydrosol yield 98 litres

Posted: Tuesday 4 January 2022