seanl
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![[*]](./images/corporate/default_icon.gif) posted on 26-5-2007 at 10:11 PM |
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Distilation Procedure
The Novice Alchemist's Table-Top Distillation Guide
By Sean Loewen
Article 1: An Introduction.
This is the first in a series of articles describing the process of distillation for the hobbyist or aspiring desktop distiller.
Distillation can be fun and rewarding but one must keep in mind that it can be dangerous and possibly illegal in your area. Take the necessary safety
precautions such as fire-proofing (a stable setup and a well-ventilated area) and fire-fighting equipment (baking soda works well), expect the
unexpected, and check with local law enforcement about the legalities where you are. Also life insurance is a good idea. I am not encouraging anyone
to do anything dangerous or illegal, rather I want to highlight these areas so that that no one causes injury or insult to themselves or others.
BEWARE! Alcohol is extremely flammable and can be explosive as a vapour. I cannot caution anyone enough about this. You could blow yourself up, in
which case you won't be able to post on this forum. So be careful.
OK with that aside, this article is just an introduction really. I'm going to explain what distillation is, outline what the other articles are going
to cover, and then I'm going to give you a sneak peak on the next step. Confused? Me too. It's probably the alcohol vapors.
What is distillation? You obviously already have some idea of what it means. Perhaps you even know how it works and what happens on both sides of the
equation. Well for everyone else's sake I'm going to give a brief description, because I think this is what makes an introduction, isn't it?
Distillation is the process of using the varying boiling points of two or more liquids to seperate your mixture (such as wine) into the different
liquid compounds (e.g. alcohol and rancid grape juice) that it is made from, in as pure a form as possible. (Although why anyone would want pure
rancid grape juice is beyond me.)
Sounds simple, right? OK, maybe not to everyone. But basically you're heating a mixture or solution to a temperature high enough that one part of your
mixture (in our case, alcohol) evaporates quickly and leaves the boiling container, passes up a column and through some cooling tubes to recondense
into another container, while the water and other things drip back down into the boiling container, thereby seperating the alcohol from everything
else.
I hope you are all with me so far. If so, read on. If not, reread the above and if you have any questions please post them, I will answer. There are
no stupid questions, only stupid TV License Inspectors. (Yes, in Ireland you have to have a license to own a TV. No, I'm not joking.)
So that explains more or less what distillation is. In the following series of articles, I am going to describe:
1. What equipment can be used for distillation, 2. How to prepare your setup, 3. How
to use and control heat for distillation, 4. Performing your first distillation, 5. Checking your
results, 6. Creating higher purities, and 7. Summary and Conclusion. These articles do not cover
alcohol in general nor any of its uses such as creating tinctures or elixirs.
That's all for now. In my next article in this series I'm going to delve into all the different types of equipment that can be used in distillations
of all sizes, from on a small workbench to industrial distillation factories the size of skyscrapers.
[Edited on 15-7-2007 by seanl]
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seanl
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| posted on 7-6-2007 at 12:18 AM |
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Article 2 - Equipment
Ok in this article I'm just going to briefly touch on differnet equipment that you can use for different distillation setups. The 3 basic setups I'm
going to cover are the kitchen distillation setup, the home lab setup, and the high-yield milk can or beer keg setup.
For the kitchen distillation, here is the equipment you need:
1. A large, deep pot for boiling with a lid
2. An empty tin can with the label and both top and bottom removed
3. A heat-resistant metal or glass bowl
4. Some ice
5. A stove or other heating element
For the labaratory table-top distillation, you must have:
1. A heat source such as a bunsen burner
2. A stand or rack for your boiling flask
3. A boiling flask (flat-bottom flasks work best)
4. A fractionating column
5. A condenser
6. A receiving flask
7. A stand to hold the condenser
8. A coolant reservoir and pump system to cool the condenser
For the large-yield distillation setup, you need:
1. An empty stainless-steel beer keg or 10 gallon milk can
2. A distillation column, at least 28", preferably packed with raschig rings or marbles or something to increase surface area
3. A column head, either valve-reflux or internal reflux
4. A much larger heat source (preferably electric, for safety)
5. A significant quantity of something to distill i.e. red wine
This covers the equipment required for some different size setups. Of course you have to build your own reflux head, if anyone wants further info or
details on where to get equipment please post or email.
Stay tuned for the next article, "Preparing your Setup".
Regards,
Sean Loewen
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seanl
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| posted on 18-6-2007 at 10:17 PM |
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Article 3 - Preparing Your Setup
Welcome to the third installation in this series. Today I'm going to cover how to prepare your setup for table-top distillation using the lab
equipment. Please read the previous article for the list of equipment you will need.
As mentioned previously, the first thing you should consider is that distilation can be very dangerous. Alcohol in liquid form is very flammable and
in vapour form it is explosive, so be warned. Make sure you have some kind of fire-out-putting gear to hand just in case of an unexpected accident. A
box of baking soda works great in a pinch, a fire blanket is also good.
OK, I will now describe how to setup your apparatus. Place your heat source on a stable, even surface. Make sure there is plenty of space around your
burner or element, and also that the room has adequate ventilation. If you are burning propane or kerosene keep in mind that these fuels can produce
carbon monoxide (or is it dioxide) and if there is not adequate ventilation in the room the oxygen levels can drop low enough to cause unconsciousness
and even death. Place the stand for the boiling flask over the heat source. Make sure that if you are using an open flame that you have some kind of
heat spreader or diffuser over the flame to prevent scorching or cracking of your boiling flask. You can get an asbestos screen for this purpose or if
you are stuck I've found that a bathroom tile will work well, although you may find it difficult to get your solution up to temperature because the
tile will really diffuse the heat a lot.
Place the boiling flask on the stand and add your liquid, in my case this is good quality red wine made only from red grapes. You can of course
distill whatever you want. Now place your column and (silicon) seal into the boiling flask. Be careful at this point because it will be top-heavy.
Position your stand with clamp and condenser at the right height and angle so that the column fits into the open end of the condenser . This can be a
bit tricky and may require some practice to get at just the right position. Remember, be careful no to bump the boiling flask and stand as they will
fall over very easily. Take it easy and remember, patience. The last thing you want to be cleaning up is broken glass mixed with red wine.
Once you have the condenser and stand positioned correctly, slide the open end of the column head into the condenser tube and push together for a snug
fit. Once they are attached the whole thing should be a lot more stable. All that is required is to place your receiving flask under the open end of
the condenser. Make sure it is properly aligned, or you will be dripping distillate all over your table-top. Now it is a good idea to check that all
the seals are tight and that everything is lined up properly. Oh, and make sure your boiling flask is less than half full or else you will get red
wine going over into the receiving flask. Just make one final check to make all the seals are good and that the whole thing is stable and then you are
ready to start distilling!
If I'm missing anything here or if anyone would like to add anything, make comments, ask questions etc. this would be very welcome. I'm sure I'm
leaving stuff out and I know others know a lot more about this than I do so your thoughts would be greatly appreciated!
OK, the next article is how to use, monitor, and control your heat source for efficient distillation. Stay tuned!
Regards,
Sean Loewen
[Edited on 14-7-2007 by seanl]
[Edited on 15-7-2007 by seanl]
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seanl
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| posted on 8-7-2007 at 02:21 PM |
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Article 4 - The Heat Source
In distilation of any kind, the heat source is very important. The most common forms are gas and electric. I'm sure you could use other heat sources
such as radioctive power but I would liken this to doing a facial manicure with hedge trimmers and therefore silly. For this article we're going to
stick with electric and gas. Though not necessarily in that order.
Gas heat of course involves flame and therefore is the most dangerous option. In fact if you are doing anything but small-batch table-top distilations
where you can be watching all the time I highly recommend using electric only. Alcohol as a liquid is very flammable but alcohol as a gas is
explosive. Even with electric heat there can be a potential for explosion due to the classic sparks inside the casing of the element
when you click the heat on. And never, never have alcohol fights and then light up cigarettes afterwards.
Assuming you're doing a small table-top batch, gas is fine. You can get the small camping stoves that take a single camping gas bottle. These are
available in camping shops and from most lab equipment shops as they are a small but powerful, convenient and portable burner. Depending on the flow
of gas you're using you can get up to 8 hours of boiling on these cans, although I've found that some seem to last way longer than others, even at the
same flow setting.
One thing to be careful of with gas is a direct flame on your equipment. This can cause cracking and splitting of ceramic and glass as well as
scorching and blackening. You can get a heat-spreader screen (I think they use asbestos though I'm not sure), or if you can't get one a ceramic tile
works well (the thicker the better), although they do diffuse the heat a lot and may delay or even prevent reaching the correct temperature. They can
crack as well but better the tile than your container. If you have a proper stand you can position your container up over the flame so as to avoid
cracking. The is the best and most highly advisable solution. A heat-spreader screen is also a good option.
If you want to use electric heat, I recommend a heating mantle. They are less messy, don't need to be refilled, and provide a controllable heat
source. They can be purchased from good lab supply stores. Make sure you match the size of the mantle to the size of the beaker. You have to use a
round shaped boiling-type flask for a mantle usually.
If you have a flat-bottomed flask you can use a heating element. These range from a basic plug-in-and-boil element with no regulator or power
settings, to a digital temperature controlled scientific heating element.
Whatever heat source you use, the end result still has to be the same. If you are distilling alcohol out of a (mostly) water-based substance such as
wine, then you need to create a fairly specific temperature at the top of your column. The boiling point of absolute alcohol is 78.3 degC. The boiling
point of water is of course 100.0 degC. So naturally the alcohol begins to evaporate when the temperature reaches 78.3 degC in your boiling flask.
But, the temperature at the top of the column will be less than this, so the alcohol vapours will condense at the top of the the column and drip back
down. Once the temperature in the top of the column reaches 78.3 degC, then the alcohol vapour will flow over into the condensing chamber, where it
will be cooled and condensed over into the collecting flask.
A Note on the Azeotropic Effect:
This is where it gets interesting. As the alcohol content in the boiling mixture drops, the azeotrope effect begins to increase. This effect is always
present when distiling just alcohol and water, but increases as the alcohol-water mix changes. An azeotrope is a solution with the unique property of
having the same composition in vapour form as it does in liquid form. This causes a problem with seperating alcohol from water. Because of the
azeotropic property of a water-alcohol solution, it is difficult to get higher than 95%, even with the most carefully controlled and monitored setup.
To achieve levels above this it is usually necessary to use a ternary axeotrope, i.e. distillation using a three component azeotrope. In commercial
setups, I believe the substance used most often to alter the azeotropic mix is benzene. A mixture of 7.5% water (boiling point 100 degC), 18.5%
ethanol (boiling point 78.3 degC), and 74% benzene (boiling point 80 degC), forms a ternary azeotrope (boiling point 64.9 degC), which is a
minimum-boiling mixture. Benzene and Ethanol form a binary azeotrope (boiling point 68.2 degC). Thus, when a mixture of 95% ethanol and benzene is
distilled, the above ternary azeotrope distills first, followed by the binary azeotrope, and the final fraction (b.p. 78.30C) is absolute alcohol.
Further on in this series (see article 6, creating higher purities), I will outline another method for going above the 95% threshold.
So obviously the important place to measure the temperature is the top of the column. I have found that a very good way to do this is with a Fluke
laser thermometer. You just point and shoot and the display tells you the temperature of the thing you are pointing the laser beam at.
I have seen many different ways of regulating temperature, from manual checking and adjusting to highly sophisticated double-sensor feedback
controlled solenoid switches on the heating element. You can go as low or as high tech as you wish but I have obtained very good results just using
manual temperature checking and adjusting of the heat source. Of course I've only done small batches up until now, and I am always present when the
distilation is going on. For other purposes a more advanced method may be required but that is outside the scope of this article.
That is all for the topic of heat use and control. Stay tuned for the next article: Performing Your First Distilation.
Regards,
Sean Loewen
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seanl
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Registered: 29-4-2007
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| posted on 15-7-2007 at 01:02 AM |
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Article 5 - Distilling
Welcome back for those who are following the series. This article, the 5th in the series, describes the process of distillation as performed using the
basic table-top set as described in previous articles. If you haven't read the previous articles in this series, I recommend you go back and read them
from the 1st one on.
The following assumes you have set up more or less as described in article 3. So you have your heat source, your stand, your boiling flask above the
heat source, near enough to reach temperature but keeping in mind the risk of scorching and cracking that can occur with direct flame. You should have
a stopper fitted in your boiling flask with a hole into which the refractionating column is fitted. At the top of this is your joining piece which
connects to the condenser tube. At the end of the condenser tube you place your collecting flask. All your condensed alcohol will run down this tube
to be deposited into the collecting flask. Make sure everything is correctly aligned and positioned, make sure your clamps and stands are tightened
and are straight and well balanced.
Just a brief note on cooling: Sufficient cooling is crucial to ensure you don't get any precious alcohol vapour seeping out of your condenser. You
will need to make sure that your cooling supply is going to have sufficient pressure to fill the fluid chamber of your condenser. I use an aquarium
pump to pump the water from a holding tank into the lower condenser fluid connector, for pumping through the condenser fluid chamber. At first I had
tried pumping the fluid down from the upper connector, thinking gravity would help, but I found this created a lot of air in the chamber as the water
was escaping faster than it was going in. When I connected the water supply to the lower connector it pumped up, filling the chamber, and then running
out the top connector and back into the reservoir. You may want to have a bag of ice in the freezer in case the water starts to warm up, which is
likely, depending on batch and reservoir size.
As a final checklist, you should now have:
* Your heat source;
* A boiling stand;
* A boiling flask less than half filled with solution;
* A distillation column;
* A distillation head;
* A condenser column;
* A suitable stand to support the column;
* A coolant supply going through the condenser;
* A collecting beaker or flask;
* Lots of patience.
Make sure before you start that you will have sufficient time undisturbed to perform the entire distillation, which may take several hours. Try also
to make sure that no one is watching. Some like to say a prayer to the maker before starting. Also you should distill during the hour of mercury, and
on a wednesday as well if possible. There is a great piece of software for showing the planetary hour for your region in the taskbar. It's called
ChronosXP, and you can download it from
http://chronosxp.sourceforge.net/en/
If you have everything ready, turn on your heat. After a while you will see small bubbles starting to form. Vapour will start to become visible in the
column and the distillation head. If the mixture starts to boil fully, turn down the heat or move it slightly away from the boiling flask. Continue
like this, keeping the mixture just shy of boiling. Soon you will start to see the vapours condensing to small beads of liquid and rolling back down.
I remember the first time I saw this, it really looks quite amazing. If any one want to see photos of it I took some good ones and I would be happy to
post them.
Eventually you will start to have liquid alcohol rolling down your condenser tube into the collecting flask. Try to keep it around 1 drop every 1-2
seconds. The way you control the speed of the flow is by increasing or decreasing the heat source. If your heat source is static, you can increase or
decrease the distance from the heat to the boiling flask. There are ways of regulating temperature and flow using thermostats and solenoids, but we
are doing this the old-fashioned way. Anyway, 1-2 drops per second seems to be a pretty good rate to start at for reasonable purity. Sometimes I will
go quicker on the first distillation, until I know I have 95% of the alcohol removed (at this point I don't worry about azeotropes). Then I redistill
again a bit slower, and I continue like this for the next 5 distillations, often slowing right down to 2-3 seconds per drip on the final
distillation.
A hydrometer or alcometer can come in very handing for testing purity. But you can estimate as well, if you know the starting percentage. For example,
let's say you have a 75cl bottle of wine that is 14% alcohol. This means the bottle of wine has 105ml of alcohol, or 14% of 750ml. I do the 750ml
bottle in 3 250ml batches. I might do the first distillation run a bit quicker, until I have a total of 208 ml (when the 3 sub-batches are added
together), slowing down at the end. At this point there is usually no taste of alcohol at all in the boiling solution. I then estimate that I have
removed 99% of the alcohol, or 104ml of alcohol, which is exactly 50% of the total 208ml brought over. So you know you have about 50% alcohol straight
off the bat. Dilute this to 45% with rain water and then redistill. The way you calculate how much water to use is like this: take the amount of
alcohol you have, in this case about 104ml. You want this to be 45% of the total solution, so you just divide 104 by 45, which gives 2.31. So you fill
up your solution to 231ml (just move the decimal 2 places to the right). It's easy.
I do the second run a bit slower, bringing it down to 1 drip every second. For this run, I would distill at this rate until I have collected about
17.3ml less than I collected the last time. You work out how much to reduce the collected solution each time by taking the total reduction needed
(whatever amount isn't alcohol) and dividing this by the total number of remaining distillations. For example, as in our case, we have collected 104ml
of alcohol in 208ml of solution. So we need to get rid of an additional 104ml of non-alcohol in our 50% solution. Hence, we take the total we want to
reduce by (104ml) and divide that by the number of remaining distillations (6) and we get 17.3. So each time we distill we want to have 17.3ml less
than what we collected the last time. And by going slower on each successive distillation, we can be more likely to collect the maximum available
alcohol each time. Of course you are only likely to get between 95% and 99% of the alcohol in the solution, but we there is a further step we can take
to increase the final purity. More on that later.
After the second distillation, you should have about 190.7ml in your collector flask. Assuming we have collected 99% of the available alcohol, this
means you should have 103ml of alcohol in your 190.7ml solution. So your purity should be somewhere around 54%. Now redilute with rain water to 45%
and carry on. Remember how to calculate this? Take the amount of alcohol, 103ml, and divide by 45, giving 2.29, or 229ml. So fill up the solution to
229ml and redistill. Notice that the total solution has dropped by 2ml.
Carry on like this. On the third distillation go until you have 173.4ml of solution. This should have about 102ml of alcohol, in which case your
mixture is now around 59%. Dilute this again to 45% by bringing it up to 227ml. Then distill this even slower until you have 156ml. Dilute to 224ml,
distill 138.7ml, dilute to 222ml, distill 121.4ml, and you have performed 6 distillations, and your purity should be around 86%.
You can wait for the final article on how to get greater purity than 95% on the last distillation, or you can go straight on and do it, after which
you should have distilled about 104ml of solution, which should be at about 94% or 95%. To get this kind of purity you must distill more slowly each
time. This requires a lot of patience. I have the word 'patience' up on the wall. Believe me, it helps. I also recommend taking the opportunity to
meditate on distillation while distilling, as well as on other things.
The next article will tell you about ways to check your purity, such as with an hydrometer or alcometer. In the final article, I have a tip for
getting a higher purity final product without the use of benzene or expensive equipment.
Regards,
Sean L
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