Home Distillation of Alcohol (Homemade Alcohol to Drink)
Control Systems
Update - Peter summarised
the two alternative methods of control required..
When you have a reflux cooler on top of a packed column inside, you have
to regulate the small flowrate of the reflux cooling water system, to get
constantly 94 % alcohol during the whole proces.
The flowrate is regulated by the column top temperature.
When you have a reflux cooler on top of a packed column outside, you
have to regulate the flowrate of the reflux-distillate back into the
packed colunm, to get constantly 94 % alcohol during the whole proces.
The flowrate is regulated by the column top temperature.
I haven't yet found the need for elaborate control systems to regulate the
heat input or flow of cooling water etc. I believe that you first ensure
that the fundamental design is correct, matching the rate of cooling (and reflux
produced) to the heat input; once this is in balance the still should really
look after itself. Just set the cooling water flowrate, and check it every
half hour or so (remember the cardinal rule of never running a still
unattended !!)
Probably what is of benefit to the lay distiller however is the control over
the gross heat input. Given the long time it takes to first get the wash
up to distilling temperature, there is some benifit in having a variable power
input - so you can give it heaps to get it up to temperature, but then back off
the power once you're distilling. Two ways of doing this;
- Have two elements - one large, one small. Use both to heat up to temperature,
then only have the smaller one on while distilling. Or
- Use a single large element with a variable control on it.
Others find control systems however to be of benefit, and enjoy the challenge
of designing & tuning them. So here's their side of things.
Pilch writes ..
A 10 amp motor speed controller can do the job. For those in
Australia who want one "off-the-shelf" and not in a kit form, contact
Ian at "Likker 'n' Leather" - email: pilch@tpg.com.au
If you are not an electronics guru its a good price for one fully
assembled.
Tony writes ..
I figured that by not exiting the unwanted parts of the mash,
one have a better chance of getting cleaner alcohol. This is how I went about it.
knowing that we are only interested in alcohol, one must keep the
mash temp constant below 84 C. I achieved this by using a triac
voltage control set at (in my case) 90 volts. Initially I start at
240 volts to bring the mash to 84c, I installed a thermostat at the
very bottom of the column.when this temp is reached. A simple
electronic device incorporation a relay switches on the triac device
changing the voltage from 240 to 90volts. This works extremely well.
If one plays with the voltage one can find the balancing point for
their particular still. As a certain amount of alcohol will come out
during the procedure, to improve the reflux and the temp stability of
the mash I employed an s bend right near the top reflux control with
a constant water drip to replace the alcohol that is coming out.
I found this works very well.
Roberts solution
I had the same problem with lowering my input power to the boiler
because I didn't want to install a new element and had to work with a 2400W
element. Variable transformers that can handle up to 8A are very expensive
and triac controller would take longer than I wanted to build so I need to
put a resistor in series with the Heating element. Unfortunately to cut
down the wattage to about 1000W the resistor would need to be able to
dissipate a similar amount of power.
The idea came to use a stove element.
By measuring the resistance in the stove element and adding it to the
resistance of my 2400W heating element in the formula P=(I^2)*R and V=IR. I
found I could cut the power in half, or in thirds, depending on what size
stove element I used. (Stove elements are almost free in 2nd hand stores).
So My problem was solved very quickly and VERY cheaply.
Some warnings:
a)This system makes it very easy to electrocute oneself, so electrical
knowledge is ESSENTIAL. (It's only a simple circuit but it can kill very
easily if stuffed up).
b)The stoveplate gets very hot and needs to be in a spot where it can't get
trodden on or have stuff dropped on it.
c)The element needs to be in a ventilated area, any open space will do
Apart from that it's all hunky dory, it's not pretty, or clean, and has a
terrible power factor, but it works extremely well and can be made in 5
minutes.
I hope you find that an original idea to a common problem. I have built a
triac controller now, but in the beginning this was my original method.
Andrews Microprocessor
Andrew writes ... The still we are in the middle of building now has a 40l tea
urn, a 1m tall reflux column (now packed with SS after
reading your site), a peristaltic pump to control draw of rate
and has a whole host of electronics hanging of it.
The main things my controller will do is
- Measure input and output temprature of cooling water, then adjust flow
rate to keep a steady wattage of cooling.
- Measure temprature of still head and Log the data (so you can later graph
it on a computer to check that everything went OK.
- Measure temprature of wash (and again log this).
- Control a perstaltic pump to draw of the distilate at a controlled rate
(like the ~~4mL per minute that Stone/Nixon suggest) instead of arseing
around with a needle valve.
- Control a moterised lazy-susan/conveyor belt that changes collection
vessels at appropriat times.
All this will be done by an itsy bitsy little microcontroller and the entire
board should cost less than $150 for others to build. (it there is enough
interest I can also make a run of them for others).
Stay tuned here ...Andrew has offered to describe & detail it all, etc - a big
thanks to him !!.
Andrew also cautions about triac controllers ..
..may be hesitant about the triac controller
is that in most places around the world it is now illegal to use triacs to
angle fire loads above a few hundred watts. Angle firing large loads upsets
the power factor significanlty.
David
David Reid writes ...
You should use at least a constant load triac controller tied to a
decent temperature sensor probe such as a thyristor otherwise you are
wasting the advantage of a decent column design for start off.
If you dont
want to do that because you cant afford it or are too tight to spend the
money at least go and rip a decent simmerstat out of a stove from an
inorganic rubbish collection round and at least use that.
You definitely
need some type of control over the heating system. The chances of it being
exactly spot on are almost negligible; it will more likely than not be too
hot at times which means it needs turning down a bit. (Too cold and you
could have done with a bigger element for a startoff but 750w should be
adequate apart from bringing the mixture up to temp. Too hot and you are
boiling the guts out of the mixture stuffing up the separations).
Remember you get what you pay for.
I use a solenoid valve to turn the water off and on and a manually adjusted
needle valve to control the flow.
Please note temperature at takeoff point is different to temperature in
boiler, and can vary depending on still. This is a point where there is a bit of
disagreement over location of sensors. Some people argue that because you
want to control the temperature in the boiler which is what controls most of
the other temperatures in the column etc that this is where you need the
sensor and work from that point. To a degree they are right. I and most
people who know what they are doing adopt a slightly different attitude
knowing that the most critical temperature point in any still is at the
takeoff or condensation point. I therefore mount the critical sensor there
working backwards using insulation and other aspects of the design process
to minimise the differences between temperature at this point and the
boiler. The ideal situation is where you have 2 or 3 sensors each monitoring
different points but then the controls and the monitoring situation become a
lot more involved.
The temp sensor must not touch the cooling coils. You need to measure the
vapour temp at this point. Please note that water vaporised expands to
something like 1500 times the volume. Location and depth of sensor is
critical. So many of the people designing stills dont have the first clue
and there is so much false information out there. Before going further and
designing a controller that might work go out and research the subject
properly and read a few decent books. Most of the people designing stills
are too lazy or too arrogant to do even that. If you can see how someone
else achieved a certain goal you can admire it or fault their thinking.
Quite often you can even improve upon ther original concept. Firstly you
need to separate the chaff from the wheat. That way you may design a
controller that works. PIC controls certainly have their place and proper
intergration of these in the stills of the future will be commonplace and is
one of the better solutions available.
Jan-Willem's Triac
Jan writes ...
When the power input is too much then everything is going ballistic.
There must be a sort of relationship between power input, boiler
volume and cooling capacity.
So if you start of with a nice soft boil then that thing is covered.
With gas its easy (?) to turn it up or down, with electricity its
somewhat more difficult.
I don't know if you can build it yourself, if you do on my site is a very
simple triac controller, and that one can do 2.5 kW.
Its a very basic straightforward controller.
I experimented with a proportional controller with temperature feedback but
that was a bit overkill in my opinion.
But than again i don't run a MEGASTILL with continuous output etc etc
Its just hobby and when its running I am VERY nearby...
You can find my homepage (if my provider is still running) at
http://home.planet.nl/~jwdob
then go to distilling
Ross's Time-clocks
Ross uses time-clocks to help with the long distillation times involved
with operating a high-puirity Nixon/Stone still ...
I have both my units gravity fed from a 200lt drum
upstairs on the veranda. Using the 10 odd metres of cooling coil I find that
a flow of 250 mls/min is sufficient.
My problem is I'm on tank water and the pressure pump downstairs under my
bedroom, would cut in every 30mins and keep waking me up :((
Now I have a
solenoid water valve on a time clock which refills the 200lt drum every 12
hours. This is kinder on me and the pump. Running time clocks and solenoids
on the both stills, I can start the stills at 1am and the SS unit has dropped
about 6-7lts of 60-70% impure and [my still] has just equilibrated nicely by
7 am. The whole system is very user friendly.
It is a little early to get accurate times yet, but 5lts of water (to cover
element) and 20lts of 60-70% impure takes about 48-50 hours before the temp
rises above 80C and I turn off
Smithers Triac
Smithers (of http://go.to/distil),
who is a electronic technician by trade, suggests the following ..

IMPORTANT : READ FIRST
DO NOT ATTEMPT TO BUILD THIS CIRCUIT UNLESS YOU ARE QUALIFIED
OR EXPERIENCED WITH MAINS VOLTAGE. THIS CIRCUIT INVOLVES SWITCHING
AN ELEMENT THAT CAN DRAW 10AMPS, IF YOU FUCK UP-THIS WILL KILL YOU.
YOU CAN BUY CONTROLLERS LIKE THESE (COMMERCIAL) FROM ELECTRONIC
SUPPLY SHOPS, BUT FUCK THEY'RE EXPENSIVE.
I ran with the I.C controlled (TDA1023) without using a temp probe.
The specs on this (and application data) can be found at
http://www-us2.semiconductors.philips.com/pip/TDA1023#applications
(or download it from me here (267 kB).
You will need to download the above PDF file (page 14,15) to understand what I am
talking about below.
There were a few changes that I made for safety and to compensate for the
240V 10Amp supply that we have. They are as follows :
- D1 1N4007
- RD 6.8Kohm 10W
- RS 180Kohm
- RG 110ohm (100 and a 10)
- Triac was a BT-139-800
- Heater (load) is a 1380 Watt element. In theory this circuit could handle 2.4KW
- Ct 1uF 63V
- Rntc I replaced this with a 22kohm resister as I didn't require temp feedback
- R1 18kohm
- pin 5 of TDA1023 goes to earth to give you 400mV range control
I played around with resistors between pin 11 and Rp (40kohm) and also between Rp and
Neutral (37kohm), this was only to trim the potentiometer into the range that I wanted.
I also placed a neon indicator across the load to give me a visual on when power
was applied to the element
Cooling
The Triac requires a fair amount of cooling, I used a finned heatsink (100mm x 45mm x 45mm)
this keeps it reletively cool, I also used plastic screws, heat compound and a mica washer to
electricly insulate the triac from the heatsink.
The Resister RD dissipates approx 5W, so I advise that you heat sink this as well, this item does
get fucking hot if you don't. Mount it all in a well ventilated preferrably plastic box
That is about all I have to say about that. It works really well and I have used it faultlessly for about 25 (6 hour) runs now.
The neon indicator is a good idea and lets you know everything is working ok.
cheers
Smithers
http://go.to/distil
Andrews Temperature Control Circuit
Andrew Graham supplies details (diagram, parts list, and explanation) for how to build a cheap, simple
temperature controller at
http://www.shortcircuit.com.au/EVCA/tcc.htm.
Reimas controller
I used to run my old SS-beer barrel with a 0,6 kW immersion heater (the
ones with a 1" BSP male thread on), then I burned it up and found that
they are not made any more, so I decided to buy two 1,2 kW heaters and run
them parallel connected to get up to temperature (2400W) and then
switch them to series = twice the resistance and half the current =
0,6kW.
Here in Queensland you do not need any more if you do not have a lake of
your own for cooling water.
I have also a teeny weeny 100W cartridge element in the barrel, this is
hooked up to an ordinary dimmer switch, so this gives me 600 + (100W
with stepless adjustment for fine tuning).
PS. Dimmer switches can take up to 300W for fine adjustment-heater and
would be better wintertime, but you take what you have ;-)
See schematics below (click to enlarge).

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