Methods of Polishing Spirits

I do a two stage polishing process. Firstly i soak my alcohol with carbon for a couple of weeks - eg just pour the carbon into the storage container, swirl it around, then let it sit, giving it a shake every so often. When it has sat long enough, I then pass it through a second filter. This is a longish tube with a small hole in the base of it. I pack a little filter/tissue paper into it, then fill it with finer/secondary carbon. I attach a softdrink bottle of the spirit upside down to the top of the column, and let the alcohol slowly drip through - about one drip per second. (Actually, to be honest, I quite often dont do the second step - simply decant the clean alcohol out of the container while all the primary carbon is still sitting on the bottom. Tastes just as good.)

There are products available to help you do this easier. One is a container which you mount on the wall, which is plumbed with a valve and hose sticking out the bottom of it. Attached to the hose is an inline filter (the sort used for garden hoses). The filter is packed with the secondary carbon. When the spirit has had enough primary polishing, simply open the valve, and run it out through the inline filter. Simple.

Glenns set-up is very similar ...

When you have finished filtering your spirit, do a final filter using say 250-500mL of water. This will flush the remaining alcohol which is wetting the carbon, and save you from throwing it away. Put this back in with the next wash you distill.

Kez has optimised this ...
    I think I had a stroke or genius yesterday in filtering my spirit. I usually run a litre of water thru at the end to get the final amount of spirit out of the tube of carbon. To see when the water begins I just sit at the end and taste the spirit until it tastes diluted, which is a pretty grey area after about 20 tastes (yuk).

    So yesterday I put in a litre of hot tap water instead of cold.
    This told me 2 things.....
    1. I could feel in the tube where the water was and it told me that all the carbon was being used in the filtration.
    2. When the water was about to come thru cutting down on about 18 tastes, YES!

    To celebrate my new knowledge I had a couple of scotches. I love it when a plan comes together.

To remove any of the very small carbon carbon particles left in the spirit, you can pass it through very fine filter material - down to 1 micron pore size. This will leave it crystal clear and clean.

From Cheryl (Victoria, Canada)...(posted on
    What I have found that works well for me is, I add a 1/2 tbsp virgin oak per 2 litre container, in with the activated charcoal and treat for only 2 days (or it takes on the color, of the oak) then filter, add water to 50% and, perfect vodka.
Jack does similar ...
    Most people are familiar with "sugar vodka" and the numerous off flavors and strange tastes and smells that a pure sugar wash can create, even when carbon polished. It seems that everytime someone throws every random failed batch of wine/beer/etc into a still and "salvages" the alcohol, the vodka it produces tends to be the "smoothest batch I've made". Even though it was made from homebrewer "remnants". Rather than trying to rely on a bunch of wine or beer I'm not happy with, and can only turn into vodka, I found a method to get the smooth taste of a "random batch vodka".

    Simply make a pure sugar mash, using turbo yeast or whatever else you have handy. Ferment it out and distill it to 95% (or the best of your stills' capability). Dilute the spirit down to 40 to 50% and age it for a month on some uncharred American oak chips. About 2 tablespoons per gallon. Let this sit a month, until a nice oak flavor can be tasted in the spirit ( I try for Glenmorangie Scotch/gold in color), almost like a bland, one-dimensional, failed bourbon whiskey. THEN filter out the oak chips, add your carbon, and treat it as you normally would any sugar vodka. I have tried this with a small test batch, I am now soaking oak chips in ALL my vodka- even the stuff already carbon polished (I'll just re-polish it). After carbon treatment, there is no color and no wood flavor. The taste, however, is markedly improved. It tastes just like the wonderfull once-a-year-distill-all-the-remnants-I've-never-gotten-around-to-bottling batches people come up with now and then, but it can be done consistantly now! Appearantly the acid and tannin content in the oak mellows the spirit out through various chemical alterations/combinations, and these beneficial changes are noticable even when the flavoring compounds they form have been removed by carbon. Your sugar vodka will be the best in the neighborhood after this-and just as water-clear. Give it a try!
The following method is recommended by Gert Strand, in order to get optimum performance from the carbon.
    Activated carbon will work best when used in a granulated form as a filling in a filtration column using the following method.
    • Fill a tube 1.5 meters in length and at least 40 mm diameter with pre wetted granulated, activated carbon. Beware! The tube must be at least 38 mm diameter or it will introduce a "wall effect" where alcohol slips through the column without being purified. The filtration must go as slowly as possible without stopping, or the effects are much reduced. The filtration rate must not rise above approx 400ml per hour. Place one coffee cup of Norit activated carbon (0.25 to 1 mm) at the bottom of the column to reduce speed. With some carbons the speed can be higher.
    • To get achieve maximum effect from activated carbon the filtration must take place through the carbon bed without channeling, and in addition, the tube must be free of any air. To accomplish this proceed as follows;
    • Put the carbon in a bucket or kitchen pot and completely cover with 2-3 times more hot or boiling water. Mix for a minute and pour out any excess water. Repeat 4-5 times to wash out soluble material from the carbon.
    • Place filter papers in the tube. Fill the tube fill with warm water, then top up with the pre-wetted carbon so it flows into water and no air at all remains in the tube.
    • Filter 2-3 liters or more of water through the column to wash out any water soluble substances present in the carbon.
    • Start pouring the alcohol to be filtered directly "onto" the water so that no air comes into contact with the carbon in the tube. Filter all of the alcohol in one run, again to prevent any air from coming into contact with the carbon. Run about 1 liter of water through at the end of the alcohol to flush out the last of the alcohol. Taste the alcohol and stop collecting when you detect water.
Craig reports using a Brita water filtering system too - with good results.
Jack agrees ...
    I just started playing with my 5litre pot still again. The lack of copper in the design is causing a seriously nasty flavor in the spirit. Everything from kirsch, brandy, rum, and corn whiskey has come out tasting like rotten eggs. By stuffing a copper scouring pad into the lyne arm of the still, I took care of most of the smell, but some was still present. After several runs, the copper scouring pad was to dirty to leave in the still, so I ran the still (rum) without it. Sure enough- rotten egg smell intense enough to burn the nose. So rather than wait 2 weeks for the gas to evolve off on it's own, I put the spirit in a 2-litre soda bottle, and attached a Brita "sport bottle" carbon filter to the top. I ran some tap water through it to get the carbon dust out. I then filled the bottle with the rum. Bingo! the sulfur smell is GONE. Absolutely no trace of rotten eggs. Here is the good part, the rum flavor hasn't been stripped out at all! For those of you who have made a wine, and distilled it into brandy- forgetting that you added winemaker's sulfite- and got rotten egg brandy, just pass it through the small sport bottle carbon filter- it will remove the gas, but not the flavor. Now I don't have to wait for the stuff to sit for 2 weeks and worry about the sulfur. Heck, now I can drink it warm- from the still to the filter to the glass! Many thanks to "PK" and his brown sugar rum recipes- I'm havin' a glass of it right now!

AuntyEthyl describes his setup ...
    This system, uses a tube that is essentially sealed, so unlike other designs, you can fill and forget, rather than watch for overflow or needing to top it up all the time. It is also designed around a 25ltr wash, so will process about 10 ltrs of 40% spirit in a single pass in about 36hours.

    Secondly I apologise for the drawings, when it comes to Artistic, I'm all Autistic.


    1 x 500mm long 50mm diameter upvc pipe
    1 x 50mm end cap
    1 x 50mm threaded adapter
    1 x 50mm threaded end cap with O ring
    1 x poly pipe barbed adapter (see drawing/see text)
    1 x Caulking gun glue tube nozzle
    1 x Aquarium air tap
    1 x 1 meter+ of silicon aquarium air hose

    20ltr drum with tap
    Container to collect treated spirit (I use a fermenter)
    Some coffee filter paper
    Activated carbon
    Some untreated spirit
    Note. The poly pipe barbed fitting is the barbed part of the poly pipe adapter that screws to a tap and has the barbed part to attach some poly pipe.

    After studying my ordinary drawings, drill a hole in the centre of the end cap to suit the nozzle. This can be glued into position with silicon, from the outside. The end cap can then be glued onto the end of the main pipe. The barbs on the poly pipe fitting need to be filed down flush with the outside of the fitting, then a suitable hole drilled into the centre of threaded cap, and the poly pipe fitting glued into place. The threaded adapter can be glued onto the other end of the pipe.

    With the main filter unit built, all you need is a short piece of plastic tubing to fit over the barbed poly pipe fitting, then other end fits over the end of a standard drum tape (not the cobra/flip type tap)

    To the caulking gun nozzle attach a short peice of silicon tube. The other end is attached to the air tap. A longer peice of silicon tube is used from the tap, leading into the collection container.

    When you are ready to use...
    • Cut two layers of coffee filter paper to fit inside of the main pipe. Push these inside the main pipe until they rest at the bottom against the end cap.
    • Fill your main pipe with activated carbon, to 50mm from the top.
    • Pour the carbon into a glass bowl and pour boiling water over carbon. Stir, leave sit for a couple of minutes and pour off the water.
    • Repeat about five times until water above the carbon is clear.
    • Rinse filter housing. And fold silicon tube and clamp with a clothes peg. Fill tube with fairly warm to hot water.
    • Pour off excess water from carbon and using a desert spoon fill tube with the carbon. Once filled, screw on threaded cap and top up water in filter. Push the clear plastic tube over the tap of the drum which has been filled with untreated spirit at 50% or less, the drum has also been suspended from the garage roof truss.
    • Turn on the drum tap and adjust the aquarium air tap until the flow is quite fast, feel the filter pipe, as the spirit flows thru the pipe will cool, letting you know how far the spirit has flowed.
    • Let the spirit flow fast until about two thirds of the water has been displaced. The water can be chucked, adjust the air tap until the spirit is just flowing, about 2 drips a second.
    Relax and wait for some smooth tasting, non smelling spirit.

You could even set up a recirculating system to do the filtering .... Jan asked about this ..
    I like to have a small pump to force the alcohol through a carbon filter as i find that the drip method id too slow in winter. I intend using a windscreenwasher pump and feed the alcohol in the bottom of the filter and draw off the top.i intend to achieve a fast drip with by-pass hoses. Any better suggestions are much appreciated.
to which David replied ..
    We found the easiest way rather than using a pump which is ideal for circulating the alcohol through the carbon and which can greatly accelerate the aging and purification of the alcohol was to have a closed vessel with an outlet close to the bottom to which the final polishing carbon filter is connected and into which the already treated alcohol can be poured, decanted, or pumped, the vessel closed, slightly pressurised, and then slowly filtered.

    This produces a vastly superior product in a fraction of the time. Using a 2 or 3 stage process like this can lead to vastly shortened treatment times with each stage in the treatment process optimised.

    In the vessel mentioned above I have a tyre valve fitted into the stainless steel lid and by using a bicycle tyre pump together with a precise pressure guage I can quickly pressurise the setup to about 2 psi which seems to be about the ideal pressure and which allows me to final polish 1 litre of spirit in about 1/2 hour. The final product is as fine treated product as you will find being crystal clear and even when left for weeks has absolutely no settlement or sediment. When left to just decant by itself (everything running downhill and thus gravity controlled) it took 24 hours + previously to filter the same volume. In this setup as stated I found 2 psi to be the best pressure although you may find it varies a bit with your own setup. Exceeding this pressure quickly led to possibly channeling with the alcohol being forced through too fast and some very minor carbon settlement resulting.

    At the end of the day I found treatment and filtering rates were largely determined by the type and degree of fineness of the filter material used. Constant circulation led to shorter treatment times and ultra fine filtering led to a superior product. The main things are not to be too frugal with the carbon or to expect too long a life out of the filters. If using this method I suggest you do your own trials and tests especially of settlement and sediment. Even the clearest alcohol initially when left for some time will show very minor settlement. It is this aspect that with experience and patience you can gradually get perfect.
Kez has constructed a similar filter ..
    ..I used a bike valve to pump it up, even bought a psi gauge but found that it wasn't necesary to check the psi. I can do a litre of spirit in 30 mins and as you can see made it a flow through system so I just need to fill the container and open and close the tap.

Jan writes about freezing when filtering ...
    About carbon filtering: I Dilute the spirit app. 50/50 then use one spoonful carbon / litre (US. Quart), leave it for two days with occasional shaking.- filter through a coffee filter. THEN ---- I freeze it !!! Three days in the deep freeze at -25 deg. C. This makes the water and remaining fusels AND fine carbon particles stick together. Run it through a coffee filter as fast as it allows (filter density). What I'm left with is pure, clean, no smell alcohol which can be diluted to preferred strength (35 - 40 %).
Baker quotes from "The Alcohol Textbook" by Jacques, Lyons, & Kelsall:
    Production of vodka

    The 1982 US Bureau of Alcohol, Tobacco and Firearms (BATF) regulations define vodka as neutral spirit so distilled or so treated after distillation, with charcoal or other materials, as to be without distinctive character, aroma, taste or color. The use of charcoal filtration is now optional, whereas in earlier regulations it was mandatory and even the time and amounts of fresh charcoal to be used were specified. This change is in recognition of the relatively recent improvements in the quality of neutral spirits. Vodka is generally taken to be odorless, tasteless and colorless ethanol, but in the past in Eastern Europe vodka was lightly flavored with grasses or herbal extracts.

    It should be stressed that not only is the charcoal treatment nonessential, it is also not particularly effective and will not make a poor quality, improperly rectified neutral spirit into a good quality vodka. Neutral spirit should be diluted to about 55% before charcoal filtration. The old BATF regulations (1961) specified dilution to between 55% and 40% at a minimum contact time of 8hrs with 10% of the charcoal replaced every 40hrs to give a minimum usage of 6 lbs of new charcoal per 100 gallons of spirit treated.

    This was usually achieved by passing the diluted spirit through a series of eight or nine cylindrical charcoal filtration beds in a slow, continuous flow with one of the beds changed every day. The fresh bed would be connected last in the series. This meant that the beds were constantly being rotated; so the preferred arrangement was to set the beds in a circle to facilitate the changing. A simple alternative treatment method is to add charcoal to diluted neutral spirit in a tank and agitate or circulate it through a pump for a suitable length of time.

    The water used in the initial and final dilutions should be clean, odorless and preferably demineralized. The demineralization is generally for aesthetic purposes as consumers do not like to see a white film of salts around the side of a bottle or glass if the vodka has been allowed to evaporate.

    In countries where laws require that all spirits be aged in wooden barrels, it may be necessary to add a small amount of sugar and/or glycerin to be able to classify vodka as a liqueur or a compound spirit rather than as an immature spirit. The amount of sugar or glycerin used is normally the minimum required to provide proof obscuration. This occurs when there is sufficient dissolved material to cause the apparent proof obtained by direct testing to differ fractionally from the real proof obtained by distilling the ethanol from a sample in a laboratory still and retesting after redilution to the original sample volume.

    Great care should be taken in the bottling of vodka to prevent contamination with residues of other odorous products. The tanks and bottling systems should be washed thoroughly if previously used for other products. However, some bottlers prefer to keep a set of tanks and a bottling line dedicated solely to handling vodka. For further reading on vodka processing seethe reviews by Simpson (1977) and Clutton(1979).     This page last modified Tue, 20 Jan 2015 20:51:05 -0800