Types of Carbon

For heaps of information about Carbon, and how it works, go to the Norit site and read the section under Tech Info titled Introduction to the Porous Structure of Activated Carbon

There is also a free ebook about activated carbon at http://www.home-distillation.com/free_ebook.html

Reactivity of carbon is measured using iodine. If you can't purchase the spirit specific carbons, you may have to look around a bit for an alternative. You can see below that Charcoal is fairly useless; try to see what you can get by way of water filters etc.
  • Filter carbon : 1050 mg/g iodine absorption
  • Treatment carbon : 750
  • Contact Reactive carbon : 750
  • Charcoal : 45
  • Reactivated carbon : 90
Do not use aquarium carbon. This can sometimes be made from very dodgy sources and contain crap which will leach into your spirit. You fish won't mind, because water doesn't do this, but you will.

If you can't source any highly reactive carbon, but want to make your own charcoal, see How to Make Charcoal at Home by Dan Gill.

If you can't find activated carbon in your local brew shop ...
  • Jan recommends .. Activated carbon suppliers in Australia. The best one is in Brisbane called: GOLDCARB. 64 GARDINER ROAD. WATERFORD. QLD.4133 FAX.07-3807-8288 Phone.0418-725 783.Several grades are available and all the carbon he sells is top quality. He is a manufacturer overseas and imports it into Australia. I highly recommend him. Price depends on quantity
  • David suggests for the US ... Check out "Calgon Carbon Corporation"
  • Kev offers ... http://www.greatexpectations.co.nz/ ship internationally
  • In the UK try http://www.chemvironcarbon.com and http://www.activated-carbon.com/index.html These are the big importers of Activated Carbon in the UK, most comes from China. You can purchase small quanitys for "pre-filtering of water for Beer and Wine making", water distilling, esential oil making, etc., etc. A phone call could not hurt. Patrick.
  • Randy adds.. Activated Carbon is also used in the filtration of water for minicipal drinking water systems. They use the name anthracite. This is a food grade product. It also is sold in various granual sizes. http://www.activated-carbon.com is an example. I didnt see that they sold via the webpage. For convienience, Gert Strand or one of his authorized local distributers is a much easier (and possibly safer) solution. http://www.brewhaus.com in Canada supplies Gert Strand products here in North America.
  • Patrick ..I decided to look at US suppliers of Activated Carbon and found a few. Most say they supply the same quality carbon in 55lb bags for $1.00 a lb US! One company in particular has it for .85 cents lb. in 55lb bags.http://www.generalcarbon.com/liquid03.htm
Leigh">http://www.generalcarbon.com/liquid03.htm Leigh adds ...
    I don't know whether anyone knows this or not but you know those gas canisters used for fumes and gases on full and half face mask respirators? I get the expired ones from work, which are only thrown out anyway, because they contain activated carbon of very high quality and filtering capability. They are also very conveniently packaged in airtight sealed bags so keep indefinitely until you are ready to use them. They may be past their safe 'Use by Date' for breathing through a respirator but for what we use them for I'm sure they have years galore ahead of them. I'd be careful when using specialised gas canisters though as I don't know for sure if they include additives in canisters for acidic, alkaline or ammonia rich environments. A, B or E canisters should be fine though.
Note that if your spirit is still turning cloudy, it might be due to problems other than fusel's present ... Jessie advises ..
    I have discovered yet another cause of liquor "turning cloudly." In my case it always happened when I cut it down to drinkable strength of about 80 proof . It didn't matter what temp I distilled at, it would always happen, leading me to believe that fusel oils were not the cause. This problem had me puzzled for quite sometime, but I was always able to clean it up with activated charcoal so I didn't worry with it to much. Just the other day I discovered it was the plastic tubing I use to connect the still head to the condenser! apparently the plastic is slightly soluble in alcohol and it comes out of solution only when water is added. Plastic is no good for stills!

How does the carbon work ? Mike's simple summary ...
    First thing, some substances have the ability to attract and hang on to certain molecules by electrostatic attraction. Forget all the buzz words like Van der Waals forces, London forces, etc ... they all come down to essentially the same thing as a charged comb attracting bit of paper, the only difference being the distance the attraction works over. Carbon is particularly good at this attraction thing, which may explain why diamonds attract so many bits of fluff :-)

    The other thing about carbon is that it can be prepared so that its structure resembles a sponge, with millions of tiny passages and holes in it. This preparation is loosely called "activation". These passages and holes can control what molecules get deep inside the carbon, and which cannot ... a purely physical matter of size. It is this physical structure that primarily governs whether a particular 'activated' carbon can be used to 'target' molecules of a particular range of sizes. If you are making a respirator, then you will want to know all about that, and some respirator cartridges are best for one range of gases, but not others. In our case, we need not be so fussy as all we are dealing with are very small molecules of water and relatively huge hydrocarbon molecules ... the alcohols etc. The water can penetrate all the way into the average 'activated' carbon, but the large hydrocarbons can only penetrate by various amounts according to how big they are. Just a simple sieve thing.

    The other thing about a sponge structure is that it presents a huge surface area for molecules to stick to. So 'activating' carbon not only greatly increases its ability to deal with quantity by having a huge surface area, but also offers a degree of selectivity by physically controlling access to this surface area.

    The question of which hydrocarbons are attracted strongly to the carbon surfaces they encounter, and those which are attracted weakly, can get a bit complicated. It is not simply a matter of size. Some hydrocarbon molecules, which alone would be attracted weakly, can form a loose association with water and then be strongly attracted to carbon. Water has a boomerang shape, with the two hydrogen atoms at the tips of the boomerang and the oxygen atom in the middle. This gives it a strong negative charge on the hydrogen side and a strong positive charge on the oxygen side (egghead/cocktail party term #1: it's bi-polar). This enables water molecules to stick to parts of some hydrocarbons and give them a bunch of electrostatic anchors to hang onto a carbon surface.

    Bottom line is that if a big hydrocarbon molecule can get to a carbon surface, and it is 'sticky' enough, then the carbon will hang onto it (egghead/cocktail party term #2: it adsorbs the hydrocarbon molecule).

    Bottom line to bottom line ... it won't necessarily stay stuck! Other molecules can come charging in and knock that molecule off the carbon surface it was stuck to (egghead/cocktail party term #3: adsorption is subject to dynamic equilibrium).

    So now you have all the basic buzzwords that will have all the girls hanging on your every word at your next party :-) In the meantime, back in your shed, you have a batch of booze to clean with carbon. What would be your best way of dealing with it?

    If you pass the booze through a tube filled with carbon, will the molecules you want to trap got enough time to infiltrate their way into the carbon granules and get stuck? Alternatively, would it be better to dump both the booze and the carbon into a container and let it get on with it over a period of time? Your choice, but I know what mine would be.

    It is pretty obvious that if you use a container and soak, then you will have to filter off the carbon in the end. If, however, you decide to pass it through a tube of carbon, will you need to do that? After all, lots of people call that carbon slug a 'filter'. Will that get rid of all the microscopic particles of carbon that are so small you cannot even see them? Not likely. So 'real' filtering is needed as well, for all those tiny particles will be laden with the hydrocarbons you have been trying to get rid of! One filtering enough? Not really ... keep filtering until the filter paper remains clean.

    Should you start out with high %abv booze and process that, or would it be better to dilute it to 40-50% ? One school of thought says it doesn't matter, and another says that the agile wee water molecules help the lumbering big hydrocarbon molecules to move around ... like fast sheep dogs agitating a slow mob of sheep. My choice, based on graphs describing the dynamic equilibrium process, would be to dilute. Final results seem to bear this out.


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