Over this past summer (Northern Hemisphere) I was working on creating and re-activating activated charcoal. I thought I'd share my efforts so far.
With regard to creating; I've built a small wood gasifier which heats wood pieces in the absence of O2 to produce charcoal. The charcoal produced comes mostly from Sugar Maple or Beech trees though it seems to work with most types wood including softwoods such as Hemlock. Besides being good for barbequing, it also seems work well for purification of spirits too. After being formed through gasification, I grind it up in a coffee mill and it seems to produce grains of charcoal about the size of coffee grounds and which seem to purify quite well without impeding the flow of liquid through the charcoal. At this point I'd be grateful for any insights into any flavor enhancing benefits or impediments any of you may have come across or if there is a type of wood best for activated charcoal purification.
With regard to re-activation after purification use, I've tried heating the charcoal in my wife's Aga oven. The advantage of using her Aga is that the vapors and gases go up the chimney. The disadvantage is the efficiency is poor and the time is required is lengthy. I have also tried microwaving which has produced excellent results in terms of reactivation for coconut shell based carbon but maple based carbon has too many metals and the charcoal sparks while in the microwave. Before I close, please understand that heating a combustible substance such as charcoal has its risks due to the flammable nature of charcoal. Buying charcoal is the safest way forward if you are in anyway not knowledgeable of the risks and how to best manage those risks.