How to make a percolated tincture

What is a percolated tincture?

If you’re looking to deepen your herbal practice, percolated tinctures are a technique worth exploring. A percolated tincture is made by grinding a dried herb, packing it into a narrow percolation column, and allowing gravity to draw the solvent (the menstruum) slowly through the herb over roughly 24 hours. It’s quicker than traditional maceration and ideal for producing stronger extracts, though it does require a little more technical care to set up. Percolations are always carried out with dried, powdered herbs — fresh material cannot be used.

Why make a percolated tincture?

Percolation can produce higher-strength tinctures because the solvent is kept in constant, even contact with every part of the herb as it moves through the packed column. This creates a very efficient extraction: the menstruum passes through once, picks up a high concentration of plant compounds, and emerges as a potent tincture.

Because the herb absorbs and holds onto much of the liquid, the amount of tincture that drips out is relatively small. This naturally creates a stronger ratio — for example 1:1 or 1:2, meaning 1 part herb to 1 or 2 parts liquid. Macerations usually produce more liquid at the end, giving weaker ratios like 1:5 unless the marc is pressed hard.

In short: percolation extracts efficiently and yields less final liquid, so the tincture is more concentrated

What is the difference between a macerated, percolated and decocted tincture?

Macerated tinctures are made by soaking fresh or dried herbs in an alcohol–water blend (the menstruum) for several weeks. The mixture is stirred periodically, then pressed and filtered. Maceration is simple, inexpensive, and works well for herbs containing mucilage or resins. Glycerine can also be added if needed.

Percolated tinctures are made by allowing the alcohol–water menstruum to pass slowly and evenly through a packed column of finely ground, dried herb. This method produces a clean, concentrated extract—often at stronger ratios such as 1:1 or 1:2—without the need for pressing. Percolation relies on careful preparation and is not suitable for fresh herbs or plants that are very resinous, mucilaginous, or prone to swelling.

Decocted tinctures combine two types of extraction. First, the herb is tinctured by maceration or percolation in a strong alcohol–water blend and then pressed and filtered. Second, the remaining marc is simmered (decocted) in water. The decoction is strained and added back to the alcoholic extract to form the final tincture, capturing both alcohol-soluble and water-soluble constituents.

Which herbs can I use to make a percolated tincture?

Use any finely cut dried herbs (there are some exceptions to this rule where a vacuum pump can be used). The particle size should be around 20 mesh, equivalent to 0.84mm, like a coarse powder. Denser plant parts like seeds and barks usually pack more easily than the lighter leaves and flowers. Starchy roots can also swell somewhat. Here are some examples:

How do I make a percolated tincture?

Ingredients

• 250g dry, coarse herb powder
• 750ml ethanolic-aqueous menstruum
  (use the appropriate ethanolic strength for the herb—typically 40–70% ethanol. The menstruum strength depends on plant chemistry).

Equipment

• Percolation cone – or equivalent ‘bottle-perc’ (a glass bottle with the base cut off)
  (It can be surprisingly difficult to find purpose-made percolators in the UK — for example, this stainless-steel percolator is only available in Australia. As a result, many people get creative and adapt glass bottles or laboratory glassware fitted with a stopcock to control the drip rate)
• Percolator stand
• Valve with drip-tap to control drip rate
• Cotton balls or filter paper – unbleached coffee filters are good
• Tamping device (e.g. a dowel)
• Measuring beaker to measure menstruum
• Scale to weigh powder
• Pen and label

Method

1. Weigh the herb.
   Place the 250 g of coarse herb powder into a container with a lid.
2. Pre-moisten the herb.
   Add approximately 250 ml of the menstruum and mix thoroughly.
   The herb should resemble moist sand—uniformly damp but not wet or sloppy.
   Cover and leave to stand for at least 1 hour to allow the powder to swell evenly.
3. Prepare the percolator.
   Place a cotton-wool ball or a folded coffee filter into the neck of the bottle to prevent fine particles from escaping.
   Fit the valve with drip-tap, and place the bottle securely in its stand.
4. Pack the herb.
   Begin adding the moistened herb to the column in three layers:
   • Add roughly one-third of the herb
   • Tamp firmly and evenly with a dowel
   • Repeat with the second and third layers
   Good tamping is essential.
   Too loose = the herb will float or channel;
   Too tight = the menstruum cannot pass through.
   Even packing creates an even extraction.
5. Cap the herb bed.
   Place a coffee filter or disc of filter paper on top of the packed herb and weigh it down lightly.
   This prevents the herb from rising when the menstruum is added.
6. Add the menstruum.
   Pour the remaining menstruum gently onto the top filter.
   Keep the drip-tap open initially so air can escape; otherwise, bubbling air pockets may disturb the packed bed.
   When the first liquid reaches the tap outlet and begins to drip, close the tap.
7. Allow to soak.
   Let the packed herb sit, fully saturated, for 12–24 hours.
   This resting phase improves extraction efficiency and produces a more complete tincture.
8. Begin percolation.
   Open the drip-tap and adjust the rate to around 20 drops per minute (roughly one drop every three seconds).
   Allow the tincture to collect until the column runs dry.
   A typical yield from 250 g herb with 750 ml menstruum is approximately 200–300 ml of finished tincture.
9. Label and store.
   Record the herb, menstruum strength, batch ratio, and date. Store in a cool, dark place.

A summary from King’s American Dispensatory:

“II. BY PERCOLATION.—The article or articles should be reduced to a powder of a proper degree of fineness, or, where this can not be done, should be sliced, bruised, or rasped, etc. They are then to be first covered with the menstruum with which the tincture is to be made, and allowed to stand until they are moistened throughout, which step generally requires from 24 to 36 hours. The whole is then transferred to a percolator, and the menstruum gradually poured on, and allowed to percolate or filter until the requisite amount has passed (see section on Percolation, under Fluid Extracts). The preparation of tinctures by percolation is, with a few exceptions, the method now generally pursued by all pharmacists of this country.”