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  • Writer's pictureEssential Stills

Laboratory QC Analysis for Essential oil content (Part 2)

Updated: Feb 7, 2023


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.


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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