Gert Strand’s  free ebook about activated carbon is full of useful tips on both purification and distillation in general. But sometimes you just don’t have enough time to read through 30 pages to find an answer to your question. Because we get a lot of questions about how to clean/prepare activated carbon before use, we’re going to explain it here using some info from Gert’s book. You can read the entire ebook on our website here (for free) if you want to learn more about activated carbon. Note that all figures and diagrams I included in this blog were created by Gert Strand and can be found on pages 22-24 of the ebook.

DOUBLE the Effectiveness of Your Activated Carbon For Purification

That’s right, you can actually increase the purification effect of your activated carbon by 100%. The secret is to both heat and soak the carbon, and then to ensure that all air is expelled from the tube in your filter system. This way, the alcohol will flow through the carbon smoothly—instead of bypassing the carbon by flowing through the channels that form when using dry carbon. Plus, this method even enables you to filter twice the volume at a much faster rate.

Step 1: Saturate Activated Carbon with Hot Water.

Pour the activated carbon into an empty, stainless steel pot (a). Then add hot or boiling water; be sure to add at least twice as much water as there is activated carbon (b). Use a large spoon to stir the water and then let the carbon to sink to the bottom (c). Pour out the extra water (d). Repeat steps (a) through (d) 4 or 5 times in order to ensure that the carbon is completely saturated with water.


Step 2: Filter the Activated Carbon through the Filter System.

Assemble your filter unit (either plastic or stainless steel), ensuring that 2-3 filter papers are affixed to the bottom of the unit (a). Completely fill the tube of the unit with warm water; then pour the activated carbon into the warm water, ensuring that all air is expelled by tapping the tube to help settle and pack the carbon (b). Finally, pour 2-5 liters of water through the unit in order to flush out any remaining soluble substances (c).


Step 3: Filter your Alcohol.

As the last drops of water pass through the funnel at the top of the filter, pour in your alcohol (Step 3). Taste the filtered water/alcohol so you know when only the straight alcohol starts to pass through and let it run into a collection container. To prevent the alcohol from vaporizing, you can cover the funnel with a lid.



Step 4: Flush the Filter System with Water.

As the last drops of alcohol pass through the funnel at the top of the filter, pour in about a liter of water to flush it out and ensure that you’ve filtered all of the alcohol through (Step 4). You’ll want to taste the filtered water/alcohol again so you know when only the water is passing through and discard the water. It's important to ensure that the water has pushed out the alcohol so the alcohol doesn't remain in your carbon!

Bonus Tip!

If you use hot water when you flush your filter system (in Steps 2 and 4), you can feel that heat from the water through the tube of the filter system, so you'll know where the water is as it makes its way down.

The method described here should increase the effectiveness of your activated carbon 100% over using just dry carbon. Page 25 of  Gert’s e-book provides additional instructions on how to increase effectiveness by 150% on pages 25-27.