Originally By Tony Ackland
Materials to Use for Still Construction
Copper is an interesting case - high levels of it are known to be dubious to your health, however it has been (and will continue to be) used for centuries in commercial stills (because of its excellent ability to transfer heat). This is because any dissolution is at such a low rate that you don't get exposed to enough of it. It is well known that the low wines produced in commercial stills can be a light green in colour due to their copper pick-up, however they are still below limits prescribed for potable water by health authorities. It would also appear that the copper helps convert some of the esters & organic acids present (which affect taste and odour), so that they're reduced. Some people who have built stills without copper have later added some back in (say using copper scrubbers for column packing), to because their highly pure (93%+ purity) spirit still had a smell present, which only went away when they put some copper in the vapour path.
For an excellent article on corrosion of metals, and the problems this causes when building brewing equipment, see Corrosion Problems in Brewing by John Palmer.
For suppliers of stainless steel (or brass) needle valves, search the following sites :
http://rswww.com/ (UK), or
Also, eBay can be a good source to find stainless needle valves
What to Use for a Boiler ?A stainless steel sankey keg, either 55L (1/2 barrel), or 27L (1/4 barrel) makes a wonderful boiler. They are solid as a tank, and the open sankey valve can be directly fitted to a flange, and a 2" copper pipe. When acquiring used kegs, please try to obtain one by legal means. Failing to return a used keg for the liquor store deposit, is frequently done, however, it is not a legal way to obtain a keg. The keg is still legally owned by the brewery
Here is a message from member 'Kegs' on the HD forums:
If you need instructions for how to remove sankey ball valves from kegs, see: http://homedistiller.org/forum/viewtopic.php?t=4705
http://www.skolnik.com specializes in steel drums (including salvage drums and barrels) which may be suitable for distillers.
What Materials are Suitable ?NOTE, usability of these materials cannot be SOLELY based upon a listing of 'resistant' to corrosion of alcohols.
This information is simply being provided AS a 'base' set of textbook information. It is NOT a recommendation of proper materials.
We at homedistiller only recommend the use of copper and/or stainless steel for your distillation equipment. Safety first!
Coulson, Richardson & Sinnott (Chemical Engineering) report that:
NO plastics (or other synthetics) should have ANY contact with high proof ethanol or or ethanol vapor
Plastic is basically fine at the low alcohol end (eg the wash), but should be avoided where it will encounter strong alcohol (such as anywhere within the still's vapor path, or to store high proof ethanol product). For alternatives, consider using copper tubing from the condensor to the collection jar, and using glass collection & storage jars.
Keith writes ...
To search, select at least one of three criteria to search on. If you wish to search by compatability level, you must specify a chemical or material.
This helps with identifying different kinds of plastic: American Plastics Council: http://www.americanplasticscouncil.org/benefits/about_plastics/resin_codes/resin.html
And this helps even more: http://www.midmichiganspe.org/education/identification.pdf Society of Plastics Engineers, Mid-Michigan Section Plastics Identification
Galvanised MetalsGalvanised metals should not be used in a distillation environment. If galvanised metals are in or downstream of the condenser, then the resultant product will be tainted with lead and or zinc, and should NOT be consumed.
If the galvanized material is used as a flange, or as the boiler, it will not impact the safety of the end product, BUT this material will quickly corrode, and become worthless as a distillation device.
Solder & Brazing(A compilation of newsgroup emails by Robert Warren, Pete Sayers, David Reid, James Witten, Howard Anders, Allan Goldsmith & Scott (the yldog) - thanks guys !)
SolderIs solder safe to use ? Tin and silver solder is perfectly safe, and in fact is commonly used for soldering copper and/or stainless steel for food use. The main "ingredients" in solder we need to avoid are cadmium and/or lead. BTW tin is the material used to coat the inside of "tin cans" in making of canned foods - ie its very safe to use (Actually steel cans of course, which are plated with tin to make them corrosion proof.) Most states in the US outlawed lead solder back in the mid 70's.
There are a couple types of solder currently sold on the market:
intro on howto solderFrom HD forums, here is a good intro howto on soldering: http://homedistiller.org/forum/viewtopic.php?t=13262
BrazingTo learn more about how to braize, see http://www.fpga-faq.org/sb-metal_hold/CD_08/TheBrazingBook.pdf
Brazing definitely makes a vastly superior job to soldering and is also more permanent too.In short there are a number of materials;
Silfos is an exellent product to use. It takes a much hotter flame, so you may need to use Mapp gas or even acetylene (it melts at around 800 °F / 425 °C ?). Quite high, compared to solder. It is a phosporous bearing product. It is unique in that you don't even have to flux the joint, but it should be thoroghly clean,as with all soldering. It is very strong, and the other feature is that it is strong enough to use to repair a hole in apressurized water pipe (you can't solder with water in the pipe) but it can be worked like a brazing rod and so you can fill holes with it.
Prices start at around NZ$30 kg and go up to NZ$400 kg for the more specialized materials. The more silver and other additives the higher the price.
Also in short you get what you pay for and the skills and experience of the welder then become important. If you have a good welder he could probably use Silphos 5% but I would probably use 15% ( Good capillary flow for tight up joints. High stress resistance) if you want a good neat job and you dont mind spending a little more. Either Silphos 15% or a bottom end Easyflow (such as 30% but a bit dearer again. Good gap filling and build up. Good flow characteristics) are probably the best for this job and the little bit more you pay for the material are generally compensated for in the welding time saved. Personally I wouldnt pay more than $80 kg. Consult with your welder as he is the guy with the experience and as long as he is honest and has the skills you should be pleased with the result. If he is an older plumber who did his time using copper plumbing pipe you should have no problems.
John writes ...
1. scour the to be soldered surfaces with sand-paper. Any kind will do. But get them clean.
2. use FRESH solder paste. This is an acid paste that melts as the heat is applied, and further cleans the surfaces. Use the paste liberally! I found that I had to restrict the paste to the very areas I wanted to solder, as that is where the solder flows.
3. Use lots lots of heat.
Is Aluminum Safe to Use ?Heres what the rec.crafts.brewing Frequently Asked Questions (FAQ) (version 2.12) has on the subject.
Aluminum has NOT been linked to Alzheimer's disease. The following is taken from "Frequently Asked Questions About Neurological Problems" at The Department of Neurological Surgery of The Cleveland Clinic Foundation (http://www.neus.ccf.org/patients/faq.html):
"There is little support for the theory that aluminum causes Alzheimer's disease, the most common cause of dementia in the United States. The exact cause of this disease is unknown, although the risk of Alzheimer's is higher when there is a family history of this disease.
[two paragraphs removed]
Workers exposed to high levels of aluminum in industrial environments have no increased incidence of Alzheimer's disease. Furthermore, careful studies to date have not shown an increased aluminum concentration in the brains of Alzheimer's disease patients.
Since there is no convincing evidence linking aluminum toxicity with Alzheimer's disease, you need not worry about exposure to aluminum in cooking utensils."
Furthermore, Brewing Techniques (Jan/Feb '95) had an article on a parallel brew experiment using an aluminum brewpot and a stainless. Laboratory analysis showed that there was no significant difference in trace aluminum levels between batches. They also pointed out that most of the Al you digest is from your food and water. And for that matter, many medical people consider copper a bigger health risk.
As for off flavors, IF this happens (hearsay IMO), it is probably the result of the brewer scrubbing the oxidation layer of the pot during cleaning. Don't scrub, use a soft cloth or sponge and non-abrasive cleaner. This is one of the reasons Al is not used much commercially, its not caustic cleaner friendly.
Cleaning AluminumTed advises ..
Is Copper Safe to Use ?Copper has been used for centuries in still design, despite its slight solubility. This is primarily due to its excellent heat transfer properties, making it excellent at cooling the vapours. Although some copper will leach into the distillate (low wines are sometimes a light green in colour), it is usually well below health limits for potable drinking water.
If you haven't fully rinsed off acids used during cleaning, then it can react to form copper acetate (verdigris). This stuff is toxic, with an LD50 (Ingestion) of 196 mg/kg (mouse). This is a small number - it means that a 90kg person would need to consume 17.6 grams of it (half a scrubber by weight ?). This stuff is slightly different from the "green rust" you see on copper if it isn't dried fully each time after use. However, all copper salts are toxic if consumed in chronic volumes. 2-5 mg / day is essential for good health, however levels above this will be dangerous. 10-20 g is considered fatal. Your body will slowly flush itself of copper, but approx 30% of copper salts ingested will stay in the body. The half life is 13-33 days with 70-150 days to completely clear any one incidence of ingestion. In simpler terms, we're not at risk in using copper for the fittings in the still, as the rate at which we're oxidising the copper is a lot slower than rate our body can handle it. In addition, given that the reacted copper is water soluble, a decent rinsing after each cleaning & use of the still should take care of removing it. The greater likely risk is from inhaling the dust when cleaning dry copper. Make sure that you do your cleaning in a well ventilated room, and possibly use a mask if you're putting dust into the air.
It would be rare to find a commercial distillery that didn't use copper.
Several sites actually recommend some benefits from using copper, as it is said to remove sulphur & form more esters (flavour)
Helge Schmickl of http://www.schnaps.co.at/ writes :
The following comments are from the Macallan Distillery at http://www.themacallan-themalt.com :
Finally, while we are on the question of still design, there is the important matter of the length and angle of the 'lyne arm' - the pipe which connects the top of the still, known as the 'swan neck' to the condenser. Macallan's lyne arms are of average length, but they are acutely angled in a downwards direction. This means that once vapours reach the neck of the still they are more likely to go over and be condensed than to fall back as reflux and be re-distilled. Again, the Macallan is unusual in this: most distillers set out to increase reflux. But then, they may well not achieve such copper contact (with its spirit-enhancing properties) as do Macallan's small stills.
At http://www.drinktec.com/ I found the following which adds to the copper knowledge base ...
Therefore, due to my experiments and years of working knowledge, I have come to the conclusion that in order to gain the desirable flavoring that copper adds, it is beneficial to have copper in the area that the most vapor will be in contact with it.
I ran these in my reflux column - 2 runs. After the second run, I left the still set for a day (my bad) and when I went to break it down, all of the 'Copper' scourers had turned to heaps of black (ferric) oxide. The ones nearest the bottom had the consistency of freeze-dried plant material, whereas the ones nearest the top still had a slight bit of structural integrity - but were still mostly black.
I should have tested them first, they stick firmly to a magnet..! If these things are actually plated, they may have had a layer of zinc deposited atop the steel before the copper. Nasty, nasty, poorly labeled junk product. Beware.
Anyway, to preface the article and to acknowlege some of the speculation regarding my last post, the culprit of the corrosion and subsequent destruction of copper stills is sulfur. According to the article the sulfur comes from the grain itself, but it can also come from bacterial infection of the must prior to distillation.
As the must is distilled the sulphur compounds wind up in the spirit. The copper in the still causes the sulfur to combine with the copper and form copper sulfate. Aside from the copper sulfate there are other oils and fats from the grains and these combine with the copper sulfate as well to form a black compound. According to Lincoln Henderson, this black compound forms on the spout of the spirit safe and he reports at the Woodford Reserve Distillery it is quite heavy. The reason why Woodford Reserve has such a thick, heavy greasy black deposit is because they distill bourbon and not whiskey. As you know Bourbon has substantial amounts of corn, and with corn comes corn oil. Chris Morris refers to it as Grunge and it smells heavily of copper. It is also difficult to remove from your skin. According to Chris Morris the grunge starts at the top of the gooseneck, the lyne arm and all the way through the condensation structure. The tail end of the Grunge eventually comes to the spirits safe. Barry Walsh notes that this effect works the other way in copper mining, in this case fats and oils are introduced into a solution heavy in copper to extract the copper from the base solution.
According to Morris the Grunge is actually a polymer called ethyl carbonate and according to him when distillers refer to EC levels in their process it is ethyl carbonate that they are discussing, the copper essentually cleans this out of the spirit.
Morris reports that to clean the grunge out they run a caustic wash through the still, what results is a waste water product that is high in zinc and copper, which cannot be processed by their local wastewater utility. Morris reports that this caustic wash is mixedw with spent mash and sold to farmers, where the addition of zinc and copper is a benefit to dairy cattle.
Bill Lumsden states that the best place to utilize copper is where it is where the hot vapors are condensing. He makes reference to shell and tube condensors which consist of a copper column with 250 narrow copper tubes inside. There is much more copper surface area in a shell and tube condensor versus a worm type condensor. In his experience he states that a spirit distilled using a worm type condensor is much more meaty and sulfury in character than that using a shell and tube condensor.
Column Stills are discussed in the article. Post repeal when the distillery business was starting over from scratch a lot of distilleries started to utilize stainless steel stills. When this occured they noticed the immediately the difference between copper and stainless steel stills. According to the article Seagrams did extensive research to figure out what was going on. Essentially, Morris states that at Jack Daniels 100% copper column stills are used, while at Old Forrester a hybrid stainless and copper still is used. In the hybrid still all the internal infrastructure of the still is copper. Mr. Henderson also interjects that they also throw a lot of copper pieces into the top of the still, basically just a bunch of short sections of copper tubing, which lasts until it essentually disintegrates. The scrap tubing that they put into the still at Brown and Foreman last about 3 years and when it is eventully removed it is very brittle, about the thickness of paper and will crumble in your hands.
Mr. Lumsden states that the life of a still varies according to the distillation schedule, basically saying the more you distill the more copper dissolves. From his experience he states a 10 year lifespan for the neck and lyne arm, For the spirits still, the main body goes first and that is usually in 8 to 10 years.
The article closes with a few observations. In one, Mr. Lumsden states that the still gives itself up to the whiskey. Mr. Murray puts it more plainly and states that copper is self sacrificial and that every time a copper still boils away it is giving part of its life to the whiskey. Barry Walsh had the most important comment to make, he states that modern distillers could get away with a small presence of copper in their stills, but there is a thing of beauty associated with large polished copper pot stills.
My observations from the article are as follows.
First these are huge stills with very thick sections of metal. The corrosion that they are experiencing is pretty dramatic considering the volume of product they put out and the size of the still. I can't imagine the capital cost involve in replacing a commercial sized still every 10 years or so.
Second, copper is only important in those areas of the still that are exposed to vapor, that way the copper can do it's thing and the end product will still be as good or close to what is produced in a all copper pot still.
For a small 'hobbyist still' and the amount of mash distilled per year, the whole problem with corrosion is insignificant. I do expect that those who use copper in the column packing will probably have to replace their packing every few runs or so.
My opinion would be to use a stainless steel tank and attach a copper still head to that, you'd be way ahead of yourself.
Cleaning CopperTed advises ..
If your still is made of copper NEVER clean it with bleach! In fact, it doesn't matter what your still is made of, DON'T USE BLEACH! it corrodes just about every metal out there. I seem to say this over and over but no one listens!!! Bleach is great for sanitizing glass, plastic and wood fermenters and is the only place that you should use it.
Winding Copper CoilsSometimes its hard to make a tight coil without crimping the tubing. Nic writes ...
So to make winding a tight coil as easy as possible you want to anneal your tubing before you start AND reanneal it whenever you have work hardened it (by bending it etc.) to the point that it becomes unworkably stiff.
To anneal copper just heat to bright red, hold for about two minutes and cool. The cooling rate is not critical since copper is not heat treatable. This will make your tubing dead soft.
The annealing process will leave a black and/or red copper oxide on surface of the copper. To remove this either scrub it off or soak in warm 20% sulfuric acid until the oxides are removed and polish if desired. Be careful and observe proper safety precautions.
You should be able to get 20% sulfuric cheaply as "battery acid" from any auto shop.
If you must use salt to pack a tube, use very fine table salt. If the grains are still too big, you can easily grind it finer with a pestle and mortar ... or even a rolling pin on a hard flat surface. It powders very easily. Taping a cone of paper around one end of the tubing makes a nice funnel that doesn't take up space inside the tubing. Tap the tube often, as advised by 'trailsendag'. Make sure the salt is very dry before you start pouring by leaving it on a tray in a warm oven for half an hour. Even iodised salt soaks up some water from the air and will not pour as easily as bone dry salt.
1. Buy tubing with wall thickess of 0.030. This is refrigeration tubing and comes in 50' coils. It's *maybe* five thousandths thicker than standard kind from the hardware or Home Depot/Lowe's type chains (but same price!!!). I'm not even sure it's any thicker, but I know it works perfectly.
2. Get a mandrel for appropriate size at least a foot long (18" is better).
3. Allow at least 2 feet to overlap the mandrel toward your lap, with the remainder out in front in the floor. Keep the tubing 90 degrees to the mandrel.
4. Now with the 2 foot section in your right hand (let it extend up under armpit if necessary), and the remaining length in the left, pull with each hand in opposing directions as hard as you can (use Zen; become 'one' with it ha ha) while only trying to bend the pipe about an 1/8 to 1/4 turn at most around the mandrel (downward toward the floor). Do NOT go any further.
5. Now examine the tubing; it should be only slightly flattened where you first contacted the pipe. Repeat step 4, pulling with all your might while adding another quarter turn.
6. Now that you're nearly half way around, turn the rig over so that the short end is sticking up in the air. Continue by holding the longer length with left hand still...and pull upward as hard as you possibly can while bending to about 3/4 way around. Repeat and finish one turn
7. Now here is the trick. You got it around and it isn't kinked and it's tight to the mandrel; now keeping constant tension on the whole works, use the *short end* to make 3-4 turns around the mandrel (leave as much as you want for water connections). Why is it the trick? Well 'cause you've turned the first few turns with the short, manageable end - and now you can grasp it for the remainder!
8. To finish means we *switch techniques*: Now stand up...and take the coil in left hand and put a tight grasp on the coil with locked thumb and fingers - and - bearing down on top of your left knee - keeping constant hard tension on the remaining tubing, *turn your wrists* outward to roll the tubing onto the mandrel. DON'T try to just wrap the tubing around like a sissy or it will not fit tight to mandrel and possibly kink. You can switch hands/legs to get a rest.
Roll down, then back up the same way and you'll have a perfect double-helix coil without salt or anything.
Figure 10' of tubing for a 4.5"-5" long double-helix for 1.5" column , and 20' for a 6 incher for a 2" column.
It's hard work for any method, so just roll a few turns and rest often. Don't rush it, as was advised earlier.
Remember, there are 3 tricks: Start with at least 2 foot and wrap first 4 or so turns with *short end*; constant, hard, tension during entire process; change techniques wrapping the last part by rolling wrists.
Gaskets & SealsTarvus gets back to basics ..
Enter flour and water... made a 'dough' mixture and smeared it into the gaps. Start still running, by the time the still hit operating temps... the dough had set.. and no leaks. :)
Using a Keg
Please see the Homedistiller Forums for detailed information regarding safe construction of distilling equipment using beer kegs.
Cleaning GlassMecakyrios writes...
I used to mix a solution of baking soda and water, but now I use a product available in the States known a Oxiclean (http://www.oxiclean.com/ABOUT.HTML) and water. I pour this into the bottle and drop the chain in the bottle as well. I place my hand over the bottle opening to prevent the cleaning solution from coming out and to keep the fishing line in place (the cork is out side of the bottle -- the cork is for easy removal of the chain/fishing line). I then shake, swish, and swirl the bottle making sure to get every inside surface as best as I can. Then I remove the chain/fishing line, and pour out the cleaning solution. I then sterilize the bottle with a bleach/water solution, and store upside down until I need it.
I have found that my chain method works better -- for me -- than the gravel method that is sometimes recommended. If the bottle is still dirty after cleaning in this fashion, your best bet is to not use the bottle, as nothing will -- to my knowledge -- effectively clean the bottle.
For normal bottles and small jugs that need regular cleaning, I just use the dishwasher. What I do is invert the bottles and jugs so that their openings are toward the bottom of the dishwasher.
In my dishwasher (and I assume most have this) there are two places that you can place dishwasher detergent -- one regular "cup" that holds the detergent for regular loads, and a smaller cup to hold extra detergent for dirty loads. In my dishwasher The smaller cup empties first and then later in the cycle the regular "cup" is used.
Instead of using dishwasher detergent, I fill the smaller cup up with Oxiclean (www.oxiclean.com), and I leave the regular load "cup" empty (If you don't have Oxiclean, just leave everything empty and run the load with just water). So, what happens is when the load starts the small cup empties the Oxiclean into the wash and gives them a hot bath with Oxiclean. Then the regular cycle kicks in -- without detergent or Oxiclean -- and rinses the bottles with clean HOT water.
Pot Scourers / Scouring PadsMake sure that your scouring pads are stainless steel or copper. Otherwise they are likely to rust. Some of the cheaper ones might be galvanised steel, and may soon break down. Stainless should be shiny whilst the galvanised is grey in appearance.
If you have found a source of pot scourers/scrubbing pads, but are unsure of how they will perform, Patrick has a simple test ..