The Osmotic Sponge: The Physics of Glycerin and the 65% Ratio

by Jason J. Duke - Owner/Artisan

Fresh Content: December 2, 2025 19:30

What is a Glycerite?

A Glycerite is a liquid herbal extract made using Vegetable Glycerin (a sweet, syrupy sugar alcohol) instead of ethanol. Unlike alcohol, which chemically dissolves plant walls, Glycerin works via Osmosis and Hygroscopy. It attracts water from within the plant cells, "hugging" the water-soluble nutrients out into the menstruum.

The Potency Audit: Glycerin vs. Alcohol

Metric Hydro-Ethanol (Alcohol) Glycerite (Glycerin + Water)
Solvent Type Aggressive Solvent. Strips oils, resins, and alkaloids. Gentle Sponge. Holds sugars, mucilage, and vitamins.
Potency High (100%). Captures the full spectrum of medicine. Moderate (40-60%). Misses hydrophobic compounds.
Taste/Compliance Very Strong/Medicinal. Hard for children. Sweet/Syrupy. Excellent for children and sensitive palates.
Preservation Indefinite (Sterile). 12-24 Months (Requires >60% concentration).
Visual recipe diagram showing the 65% Glycerin to 35% Water ratio required for shelf-stable herbal glycerites
Figure 10: The 65% Standard. (Click to Enlarge) Why we dilute thick glycerin with 35% water to create a functional menstruum.

 

1. The Potency Truth (Why It's Weaker)

Glycerites are often marketed as "Alcohol-Free Tinctures," implying they are equal in strength. They are not.

Glycerin is a polar solvent, similar to water. This means it is chemically incapable of breaking down Resins (Myrrh, Pine) or efficiently extracting Alkaloids (such as Goldenseal or Lobelia). It also struggles to hold Volatile Oils in suspension.

When you choose a glycerite, you are trading Potency for Flavor and Safety. You are getting the water-soluble profile of the plant (sugars, tannins, mucilage, vitamins), but you are often leaving behind the heavy medicinal compounds that are responsible for the plant's most potent effects.

2. The 65/35 Golden Ratio

Never use 100% Glycerin on dried herbs. It is too thick (viscous). It acts like molasses—it surrounds the plant material but cannot penetrate the cell wall to retrieve the medicine. It will dehydrate the herb, but it won't flow.

The Role of Water: You must add Distilled Water to thin the glycerin. This reduces viscosity, allowing the menstruum to soak into the dried herb (re-hydration) so the glycerin can pull the constituents out.

The 65% Rule:

  • Why 65% Glycerin? This is the "Preservation Floor." Below 60%, the sugar content is too low to prevent bacteria and mold growth. 65% is the safe standard for shelf stability (1-2 years).
  • Why 35% Water? This provides enough fluidity for extraction while keeping the total water content low enough to prevent spoilage.

The Standard Glycerite Recipe (16oz Batch)

Goal: 16 ounces of Liquid @ 65% Glycerin.

  • Vegetable Glycerin: 10.5 ounces
  • Distilled Water: 5.5 ounces
  • Method: Whisk together until the "swirls" disappear and the liquid is clear. Pour over herbs.

3. Top 10 Herbs for Glycerin

Since Glycerin is gentle, we use it for herbs that have delicate flavors, soothing properties, or nutritive value that alcohol might destroy.

The Soothers & Aromatics

  • 1. Marshmallow Root: Glycerin preserves the "slime" (mucilage) that soothes the throat. Alcohol destroys this.
  • 2. Slippery Elm: Like Marshmallow, this bark requires a water-based solvent to stay slimy and effective.
  • 3. Lemon Balm (Melissa): Glycerin captures the bright, citrus top-notes without the "burn" of alcohol masking the flavor.
  • 4. Chamomile: Makes a sweet, calming syrup for children or sleep support.
  • 5. Rose Petals: The astringency and floral notes are perfectly preserved in the sweet medium.

The Nutritives & Beauty

  • 6. Milky Oats: A classic restorative nervine. Glycerin holds the milky latex and minerals beautifully.
  • 7. Pearl: (The Beauty Secret). Using hydrolyzed pearl powder in glycerin creates a "Luminous Suspension." It doesn't dissolve the calcium like vinegar, but it suspends the proteins for a luxurious beauty tonic.
  • 8. Elderberry: Often made as a syrup, but a 65% glycerite is a shelf-stable, sugar-free alternative for immune support.
  • 9. Holy Basil (Tulsi): The adaptogenic properties taste delicious in glycerin, making daily compliance easy.
  • 10. Mullein Leaf: For lung support, glycerin extracts the soothing properties without the harshness of ethanol.

Phase 2: The Solvent Spectrum (Applied Chemistry)

You have analyzed the Hydro-Glycerolic Bond. Now, proceed to Lipophilic Infusions: