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Laboratory QC Analysis for Essential oil content (Part 2)

  • Writer: Essential Stills
    Essential Stills
  • Feb 6, 2023
  • 3 min read

Updated: Feb 7, 2023

Assembly

Place the mantle on a secure site, close to power, water and drainage facilities.

It is best to assemble this laboratory QC kit on a suitable worktop taking into account

the height of the complete apparatus (approximately 1.2m)

and the fact that the condenser will need cold running water and drainage: a 230V standard power point should also be available nearby.

The heating mantle should be situated on a flat surface and the 2 litre flange flask carefully placed in it and pushed into place.

The test material (cut into small pieces) should be placed into the flask. A typical quantity would be 100g and the flask can then be half filled with roughly 1.0 - 1.2 litres of clean tap water.


How to obtain a representative sample


The crop to be distilled is usually supplied in tonne bulk bags or some sort of similar containers. Visually inspect the contents of each pack to ensure that the material looks similar throughout and there are no patches of crop that have a different colour, texture or other physical characteristics to the main bulk. Assuming all the consignment is

homogenous, then take samples at random from at least 5 different points - top, middle, base, centre and outside and place them in a bowl. Manually mix the contents of the bowl and then take your testing sample from various points throughout the mixture.


Apply a little silicon lubricant on to the flange and spread evenly so that all surfaces are lightly covered. Affix the flange top in place and centralise, mating the two surfaces together.

It may be necessary to slightly open the clip on the first usage as this can be stiff. Affix the clip around the two flanges, so that they become securely joined.



Grease the surfaces of the stopper and fit into the side socket on the flange lid.



Lightly grease the cone of the Dean & Stark and

insert into the central B29 socket in the flange lid.



Insert the support rod into the base of the retort stand and tighten. Position the retort stand to the rear of the mantle.

Slide the boss and laboratory clamp down the rod so that it roughly lines up with the B29 socket situated at the centre of the flange lid and this can then be used to support the flask. Open the prongs on the clamp and fit it over this socket where the Dean & Stark lower cone fits. Adjusting the clamp length as appropriate and lock in place using the thumbscrew after 'centralising' the jaws as appropriate.


DO NOT OVERTIGHTEN.


Place the ends of the rubber tubing in hot water for a short while to increase flexibility before carefully affixing over the inlet and outlet spigots on the condenser.

The tubing is fitted so that the lower pipe goes to the cold water tap, with the upper one going to the waste. Grease the cone of the condenser.





Affix the swivel bosshead and clamp on the support rod so that it lines up with the socket at the top of the Dean & Stark apparatus: this can be rotated in its socket to assist in orientation. This will support the condenser that can now be and affixed into the socket at the top of the Dean & Stark.


Turn on the water so that it flows through the condenser as a gentle trickle. Remember - Always water in at the bottom and out at the top.

Picture below shows assembled apparatus: (for clarity the lower boss and clamp have been removed).




Your equipment is now ready to use.


 
 
 

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More Information

 

 

What is it?

 

This Still comprises a boiling vessel with 6 elements at the base and a basket inside. A tall steam collection cone is fitted on top of the boiling vessel that carries a bend at its top that then joins onto an open horizontal 4” tube. This tube ends in a 90° bend that points downwards and this then joins on to the condenser with a 4” screw fitting.

 

​The condenser is a beautiful piece of kit with 36 narrow (8mm) thin-wall tubes fitted equidistantly within a 4” diameter stainless outer tube: there are 3 sets of baffles fixed at set intervals to make the water ‘chicane’ and maximise agitation and therefore improve its cooling capability. There is a cone at the base of the condenser to direct the distillate into the glass Florentine fitted directly underneath.​

 

How it Works:

 

The water boils, the dry steam goes through the plants in the basket collecting a bit of essential oil on the way and continues up the cone: at the top it turns 90°, goes through the top pipe and then heads down through the 36 pipes in the condenser. Since these pipes are surrounded by cold water, the steam then condenses into liquid and drops into the glass Florentine that is placed underneath. Here any oil present will separate and float to the surface, while the condensed water then trickles back to the boiling vessel via the S trap mounted a few inches up from its base.

 

​How to Operate:

 

Lift off cone/condenser unit and slide to one side and remove basket. Fill vessel with 40 - 50 litres of water, enough to cover the elements with say, an inch of water on top. Line basket with muslin and fill it with the material you want to distil e.g. lavender - and place it back inside the boiling vessel. Some form of lifting apparatus will be required e.g. simple sliding block and tackle. ​Slide cone/condenser unit back and lower onto boiling vessel, lock the clamps so that it all becomes one unit and turn on the heat. The Still has a wrap-around fabric insulation jacket made in two sections and one goes over the cone whilst the other goes around the boiling vessel. As the Still heats up, you can turn off some of the elements until a nice rolling boil is achieved. Make sure water is gently flowing through the condenser to keep it cold and the distillation continues until the oil layer in the Florentine stops growing. Then turn off heat and water and remove oil.

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