What is it?

This still comprises a stainless steel boiling vessel that sits directly on top of a second chamber: this lower chamber is fitted with a special 3 kW heating element designed exclusively for this purpose and is connected to a vented expansion/filling tank mounted on the side of the boiling vessel. This lower chamber and expansion tank are filled with heat-transfer fluid and the tank accepts the excess fluid as it expands and contracts during the distillation process. A sight-glass is included on the side of the expansion tank for this purpose.

​The boiling vessel is designed to hold a 50 litre charge basket fitted with a mesh base. The basket is filled with the plant material and fits inside the boiling vessel: the basket will be suspended above the boiling water, so that it can be used for the distillation of most perfumery plant materials.

​A second stainless steel jacket fits around this vessel that is packed with Vermiculite insulant and this covers both the walls of the boiling chamber as well as the walls and base of the heating chamber.

​The boiling vessel can drain through an orifice via a ½ inch 90° bend that is welded onto the base. This bend terminates in an 'L-port' valve that ensures the boiling vessel will remain free from any pressure build up because it is locked in the open position: it also carries a vertical pressure relief pipe on its vertical (open) arm.

​A stainless steel cone fits on top of the boiling vessel and can be locked in place. It is fitted with a 100mm flange at its top: this flange has a PTFE gasket and is then fitted with a Pyrex ground glass flange lid equipped with a single central B29 socket; the flanged surfaces are secured together with a stainless steel clip.

​A hand-blown specially customised 'Dean & Stark' apparatus fits into the B29 lid socket and this is supported by using a customised boss and clamp. The boss is affixed to a vertical stainless steel supporting rod that is securely clamped to the back of the boiling vessel for this purpose.

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Finally a highly efficient glass condenser fits into the top socket of the Dean & Stark apparatus and this is also supported using a second boss and clamp affixed to the same vertical stainless steel rod. This condenser is coupled to tap water using rubber hoses to produce the required cooling to condense the steam.

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There is an additional 20 litre stainless steel charge cylinder supplied so that the apparatus can also be used for solvent extraction of plant materials. This means it can also produce oleoresins and concretes. If spices (e.g. nutmeg, ginger, clove, capsicum etc.) are placed in the cylinder and solvent-extracted, then an oleoresin will be produced, but if flowers are used instead (e.g. jasmine, ylang-ylang, tuberose, oak-moss etc.) then a concrete will be formed. Appropriate laboratory glass distillation kit is supplied so that the solvent used in the extraction can be recovered for re-use, whilst the flange-necked flask means that after the solvent has been distilled off, the oleoresin or concrete can easily be removed.

How it Works: 

The Mini Still Plus can be used with most standard perfumery plant materials including flowers, leaves, bark and many roots etc. The water boils because the heater element heats the heat-transfer fluid which in turn boils the water. This is highly efficient because the boiling vessel is highly insulated. The basket is fitted with a top rim that rests on the top flange of the boiling vessel, keeping it suspended above the boiling water. The basket is filled and placed in the boiling vessel that has been filled with about 10 litres of water so that when the water boils, dry steam passes through the basket and up the side arm of the Dean & Stark to the condenser. Here the steam condenses and the condensate drips down into the main body of the Dean & Stark where the oil separates, whilst the water returns back to the boiling vessel. Distillation continues until the oil level does not increase over a period of say 20 minutes.

​If the still is to be used for oleoresin or concrete production then the charge cylinder (and not the charge basket) should be filled with the appropriate plant material: the charge basket is removed. The extracting solvent (such as hexane) is poured into the boiling vessel and the cylinder is then placed on top of the boiling vessel where the Dean & Stark would normally fit. The flange top is then fitted at the top of the charge cylinder and the original glass condenser again fitted into its central socket. A glass adaptor is fitted to the top of the condenser and this is fitted with a short length of rubber tubing that couples it to the 'L' port valve situated at the bottom of the boiling vessel. There is a T-piece positioned near the top of this tubing to allow a second flexible pipe to branch off and vent the apparatus safely outside: this ensures that there is no chance of a flammability risk in the room if the solvent vapour does not fully condense.

​When the extraction is deemed complete, the heating is turned off and the apparatus allowed to cool. The 'L' port tap on the outlet is turned to allow the solvent-solution to drain into a suitable container: it is then distilled using the laboratory equipment provided. 

​The distillation kit comprises a 2 litre flange-necked flask fitted into a heating mantle that is placed on a lab-jack. The flask fitted with a 100mm flange-top, with a central socket for the distillation head, condenser, vented take off bend and a 2 litre round bottom receiving flask supported on a cork ring. The flange-top also fitted with a second socket and this accepts the cone from a separating funnel, enabling the solvent used for the extraction to be continuously added. The recovered solvent is then stored ready for re-use.

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How to Operate it: 

For the first-time use, the heat-transfer liquid is poured into the expansion tank via its filler cap: the fluid will then fill the lower boiling chamber. Continue adding until the fluid level just appears on the sight glass, then close the filler cap (obviously the expansion tank is still vented for safety reasons).

​The boiling vessel is roughly filled with about 10 litres water and the charge basket pre-filled with a known weight of plant material is placed inside. The stainless steel cone top is fixed in place and the side clamps lock it down onto the boiling vessel. Rubber tubing is fitted to the condenser inlet and this is coupled to the tap, whilst the tubing on the outlet goes to waste. Water should then be allowed to flow as a steady trickle. All the glassware joints are well silicon-greased prior to fitting them together and the Dean & Stark and condenser are supported with clamps. The heating is then turned on and once boiling point has been reached, turned back so a regular 'rolling boil' is achieved with about 3 drips per second falling from the condenser.

​The 'L-Port' valve fixed to the outlet must remain locked open to ensure that no pressure can build up during the distillation process.

​The essential oil will accumulate in the Dean & Stark and may need to be drained off at intervals if the measuring arm begins to get full – this is possible for high yielding oils such as Lavandin etc. Continue to distil until the layer of essential oil stops increasing.

​If the still is to be used for oleoresin production, the charge basket is removed from the boiling vessel and about 10 litres of the appropriate solvent then poured inside. The top cone is then fixed in place and secured with the snap-locks. The mesh support disc is located in the base of the charge cylinder and a known weight of plant material for extraction packed inside it: the cylinder is then located on the flange top on the stainless steel cone so that the two flanges fit together with a PTFE gasket fitted between them and secured together with the same stainless steel clip that was used to fix the glass flange to the cone's flange top. The glass flange is now sited at the top of the charge cylinder and secured with a second stainless clip, again fitting a PTFE gasket between the two mating surfaces. All glass sockets and cones are silicon greased and the glass condenser is then fixed onto the socket using the appropriate glass adaptor. The B24 side socket on the flange top should be blanked off with a stopper and the glassware should be supported by a clamp, using the vertical support rod that is fitted at the rear of the boiling chamber. Finally, a B24 glass adaptor fitted with a short length (150mm) of flexible (rubber) tube is fitted into the top socket of the glass condenser and the open end of the tube fixed to a T piece and supported by a clamp. A length of tubing is fitted on to the vertical arm of the 'T' piece and this goes directly down to fit onto the spigot situated on the top arm of the 'L'- port valve that is mounted on the bottom outlet of the boiling vessel. Finally a piece of tubing is affixed to the remaining arm of the 'T' piece and this tubing is supported so that it cannot kink and vents safely outside.

​The heating is now turned on and the solvent will soon boil, so that its vapour travels up the stainless charge cylinder through the plant material to reach the condenser at the top. Here the vapour condenses and drops back down the charge column extracting the oleoresins on its way down and this slowly accumulates in the flask. Since the solvents are usually low-boiling the heating should be carefully controlled and the flow of water through the condenser increased to ensure that no vapour escapes through the outlet pipework at the top.

Continue refluxing until the extraction is considered complete: this is usually less than an hour but this will be determined through experience. Turn off the heating and then turn off the cooling water to the condenser a few minutes later. Once the solvent solution in the boiling vessel has cooled right down, it can be tapped off using the 'L'-port valve on the boiling vessel so that the solvent solution flows into a suitable container.

​The lab. distillation equipment is then used to distil off the solvent (as outlined above) with the round bottom flask half filled with solvent solution that has just been prepared. Gentle heat is applied via the mantle and the water turned on so that it flows steadily through the condenser. The solvent boils and distils over and collects in the receiving flask, leaving the oleoresin behind. More of the solvent solution is added to the boiling flask to keep it topped up and when the receiving flask is nearly full it is replaced by another empty one: the recovered solvent is poured into a suitable container for re-use on the next extraction. When all the solvent has been distilled, the heat is turned off and the apparatus allowed to cool. The oleoresin (or concrete) can then be removed form the flask with a spatula and stored in a fridge in a suitable container.

Note: If the charge cylinder is filled with flowers rather than spices then you get concretes, instead of oleoresins. If you take the concrete ( e.g. tuberose concrete or jasmine concrete), put it in a flask and dissolve it in pure alcohol there will be a part of the concrete that doesn't dissolve – usually a small amount but in some cases up to 50% or so. The slurry is then put through a filter and the sludge and filter rinsed with alcohol. When the filter is examined, the glop that has been filtered out has zero fragrance... and can be thrown away. The combined solutions are then distilled once more to remove the alcohol... and what you have left is called an absolute – i.e. it is the alcohol-soluble version of the concrete.