Inexpensive Worktop Alembic Still for Fragrances (a Simplified Miniature of Industrial Stills)
by Ashhari in Workshop > Science
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Inexpensive Worktop Alembic Still for Fragrances (a Simplified Miniature of Industrial Stills)
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I've always wanted to try to make essences and scents at home, eventually concocting perfumes. Not only is perfumery at the intersection of scientific areas such as botany and biochemistry, but it is also a supremely artistic affair - a journey for mind, body and soul!
See the towering Papa Still on the left? This is an industrial steam distillation unit (photo courtesy of lpmie.net).
One of the two most basic and traditional processes in extracting chemical compounds with a strong aroma is distillation. (The other is enfleurage, if you're wondering.)
In this Instructable, I'm going to show you how I made an affordable, functional apparatus for simple steam distillation. In effect, it's a smaller, simpler version of that giant commercial system. I give you: Baby Still, the wee thing!
This is no high-precision laboratory setup, but I've made countless pleasant hydrosols and essences with it, which we've used about the house in cooking and in air freshener and eau fraîche preparations. I've even managed 5 - 10% yield in extracting essential oil from citrus rinds and certain dried spices (quite close to industrial figures). Not much to look at, but certainly effective when used appropriately!
Supplies
This is going to be long, sorry!
A note before we come to the list:
My aim when brainstorming the design was primarily to keep the cost and labour down. This set-up cost me less than 2000 LKR (~ 10€ / 15$) and about two weekends to build.
My Sri Lankan roots provided a possibly unfair advantage. It occured me to that an extremely common, traditional South Asian cooking utensil had just the right shape and features to serve as a boiling and evaporation chamber, with a few alterations. It's called a 'pittu bambu' in Sinhala (Photo 1, from laabai.com), and makes the delicious, heavy meal 'pittu' (Photo 2 courtesy of kitchensimmer.com, for the foodies) .
Even if you live outside the Indian subcontinent, where pittu bambus are easy to find, there's a good chance of finding a similarly shaped utensil used in your culture. Alternatively, you might be able to find them at little foreign groceries, or have them delivered cheaply online. Here are two links that show what you should be looking for. (This is not an advertisement or promotion.)
1) https://picclick.co.uk/Puttu-Pittu-Maker-Traditional-Puttu-Kudam-1-Unit-233716372846.html
2) http://afford.lk/index.php?route=product/product&product_id=625
The first link shows the simplest design, which is all you'll need here. The second is a bit thicker and fancier, but will do too. Beware: it will resist the drill more, and you'll have to remove the knob on the lid first.
Now, on to the list:
1. Pittu Bambu or similar heat-resistant utensil (these are typically made of aluminium or SS)
2. Ordinary pot or basin for cooling (preferably metal, for better heat loss)
3. Copper tubing (1/4" in diameter, of a gauge bendable by hand. I used about 1m of it, but a longer tube would provide more coils, and hence more efficient condensation. Just make sure you can fit the coils into your cooling basin.)
4. Polysiloxane cartridge (e.g. Silicone) + gun (a spatula could suffice, but it's a pain in the neck :P )
5. Electric or hand drill
6. Something to wedge between tubing and basin to keep tubing from collapsing (I've used a squat bit of PVC pipe)
8. Old rubber gloves or similar material to act as gaskets
9. Safety equipment for each stage
***The following is not for making the still, but rather for using it.***
For running the still, you will additionally need:
1) An electric or gas-fired hob or similar heat source
2) A flat, steady base to rest the condenser on (I make mine out of thick tomes or random boxes of ingredients lying in the kitchen cupboards :P)
3) Ice and chilled water at hand for the duration of the run
4) A little cup to empty and refill the condenser basin, or to aid cooling by pouring water over the tubing as I do in the video
5) A large container to hold spent water removed from the condenser (reuse this about the house! :) )
6) An appropriate vessel to collect the condensate (glass jam jar with tightly fitting lid will do)
8) A little aluminium foil to cover the vessel and reduce evaporation of the aroma
7) Something conical to act as a spout, so that the condensate pours into the collecting vessel uniformly (optional)
8) A syringe, for sucking up essential oil (if present)
9) An appropriate raw material! :)
Step 1 - Assess Your Components
(Don't mind the bit of a different project visible under it. Or the fact that I've written 'solvent' for 'coolant'! I initially thought of fitting a tap to drain the cooling water, but decided against it later since it was time-consuming and non-essential.)
It's important to have a good idea of how each part connects to the other before you start the next sections.
We'll call the right side of my drawing (where boiling happens) the evaporator, and the left side (where the distilled gases condense) the condenser.
Step Two - Bending the Coil
You may use a pipe bender if you have one.
I didn't, so I plugged one end of the pipe tightly with some Styrofoam, duct tape and sewing (Photo 4); packed the tube with salt; sealed the other end; bent the tube into shape, and let the salt out. Ideally, there should have been no air spaces, but there were a few, so I don't have the perfectly round coils I aimed for :(
The main concern is not to obstruct airflow by bending the tube too much, so this is okay. You should have something like Photo 5.
Step 3 - Drilling for the Tubing
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Mark the entry and exit points for the pipe on your evaporator and condenser.
THE EVAPORATOR
The pittu bambu can be disassembled (Photo 6, from daraaz.lk) into three main parts: the pot, neck and cap. There's also a disc with holes in it that separates the contents of the neck from the water in the pot - we'll call this a 'sieve plate'.
The cap concerns us now. Mark the centre of its top and drill a hole in it just large enough for the copper tubing to fit snugly. (Photos 7 and 8)
THE CONDENSER
The other end of your copper tube must pass out through the wall of the condenser. Mark this point too and drill a snug hole. (Photos 9 and 10)
Wear safety equipment when drilling, especially if it's an electric drill! I put on goggles and covered as much skin as possible for good measure.
I didn't have the clamps necessary to hold the workpiece in place while drilling, so I used ye ol' mates Gravity and Friction to restrain it, as the photos show. Worked like a charm!
(Exercise common sense and make sure you're not taking any silly risks, though, if you decide to MacGyver it as I did!)
Step Four - Assemble, Stabilise and Seal
If the fit's a bit too loose, add some bulk to the tubing by wrapping layers of thread around it and knotting tightly (as seen in the cap end of the tube in Photo 11).
The coils will try to lie lopsided on the condenser floor at this point. This will cause pooling of the distillate in the coils, so you'll have to prevent this. Wedge something solid and heat resistant between them and the condenser walls and tie them to it to keep them upright. (You could bend your coils slanting downwards and have the spout exiting the basin at a downward angle to let gravity guarantee smooth distillate flow, but I found drilling and sealing a hole for this kind of arrangement too complicated for me...)
Once you're happy with the fit apply Silicone to holes and tubing, so as to seal any gaps where they meet. The pittu bambu cap will also likely have some holes punctured in to it; seal these too with Silicone. I also used a small blob of Silicone to secure the tubing to the condenser tub; it's holding perfectly well (Photo 12).
Once the polysiloxane has cured (say, a day later, to be safe), you can fire up the still for a test run. Your two components should look like in Photo 13 (the old Silicone nozzle I use to extend the spout is optional). Use water and look out for any leaks or escaping steam. I had a little trickle at the condenser spout which took a few runs and a fair amount of silicone to fix (which is why there's a cup under the area in Photo 14, the second trial run).
Some steam (and aroma!) may escape where the cap neck fits into the pot. This is where your old-rubber-glove gaskets come into play. I have an almost perfect seal using the eyesore of a patchwork gasket in Photos 15 and 16. I sewed glove fingers in a ring! It ain't stupid if it works, eh?
And that's that! Steam distillation without expensive borosilicate equipment is now within your reach - albeit in modest quantities. The satisfaction and pleasure as myriad different chemical compounds drip-drop into your jam jar is thrilling!
I hope you've got some good ideas from my experience. Good luck with using them in your projects! :)
Further Ideas and Remarks for Makers
FURTHER IDEAS
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The following will cost more time and money, but will certainly improve the efficiency of the still.
* To allow more control over the distillation process, one might insert a thermometer into the cap. A specific range of compounds may then be distilled by manipulating the amount of heat supplied to the evaporator.
* A stirrer may be inserted into the pot either from above or a side. This could improve yield and reduce run time.
* The cooling of the coils may be automated. At the very least a water pump could be connected to the condenser such that cold water (or another safe and effective coolant) is pumped in and the warmer water removed at the touch of a button.
* The sieve disk of the pittu bambu may be fixed permanently in its place, and large heat-resistant beads packed into the neck area. This should mimic a fractionating column. Combined with a well-placed thermometer, this will allow specific compounds to be distilled quite precisely: simple steam distillation no more, but fractional distillation!
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REMARKS
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* Note that an inherent advantage of the pittu bambu for this job is that the neck section can hold material large enough not to fall through the holes in the sieve disk, so experimenting with immersing material directly in the boiling water or suspending them above it in the steam is possible.
* This is only the beginning. You'll have to do a good spot of reading to use appropriate raw materials for this kind of extraction, and you'll learn how packing of the raw material and varying temperature can affect yield. I've only explored the tiniest bit of this fascinating terrain myself!
* Opening the pittu bambu to look inside is cumbersome since the fit is tight, so plan not to do so until you've switched the cooker off.
* Make sure whatever you extract is safe for consumption or application on the skin. You will be getting fairly concentrated compounds - certainly more concentrated than in nature. They cannot always be used as the natural materials they are extracted from are. Some are toxic, and some are irritants.