How-to · updated 10 August 2026
This covers equipment and process only. We do not advise on applying ozonated glycerin to skin, mouth or anywhere else in or on the body, and these are not FDA-approved medical devices. Speak to a licensed healthcare professional about use.
Buy USP or food grade, and check it
"Glycerin" covers products that have very little in common beyond the molecule. The one specification worth insisting on is USP or food grade at 99.5% or better, with a certificate of analysis from the supplier.
What you are avoiding is crude or technical glycerin, much of which is a by-product of biodiesel manufacture. It can carry residual methanol, catalyst salts and assorted matter from the feedstock. It is sold cheaply and legitimately for industrial use, and it has no business in a process like this. Ozonating unknown contaminants does not remove them; it gives you oxidised unknown contaminants.
If a listing does not state a grade, treat that as the answer rather than as an omission.
Vegetable, synthetic and the label
Glycerin is produced both from plant oils and synthetically from propylene. Purified to USP, they are the same compound and behave the same way under ozone. "Vegetable glycerin" tells you about sourcing rather than about performance, which may matter to you for other reasons.
Palm-derived glycerin is common. If sourcing matters for what you are doing, ask, because the label often will not say.
Water content is the thing that creeps
Glycerin is strongly hygroscopic: left open to a humid room it pulls water out of the air and keeps doing it. A drum opened repeatedly over a few months can drift meaningfully off its original assay.
This matters because water and glycerin do not behave the same way under ozone. Ozone is far more soluble in water, and dissolves into it much faster. Absorbed water gives you a mixture behaving partly as an aqueous system, so a run reproduced exactly is not reproducible after all — and you will not be able to see why.
- Buy a container size you will actually get through, rather than the best price per litre.
- Keep it closed. Decant what you need and reseal immediately.
- Do not leave the working vessel open to the room before a run.
- If a batch behaves unlike the last one, water is a more likely culprit than the generator.
Before the run
Store sealed, cool and out of direct light. Glycerin does not need refrigeration and gets awkwardly thick when cold, so a cupboard is usually better than a fridge.
Decant into the glass vessel you are actually going to use, and do not pour it back into the source container afterwards. Once a quantity has been through a run it is a different thing from what is in the drum, and combining them makes both untraceable.
After the run
Ozonated glycerin holds ozone in solution rather than bound into the molecule, so it starts losing it as soon as the bubbler stops. Storage slows that down and does not prevent it.
- Glass, not plastic. Residual ozone will work on a plastic container, and the container will work on the contents.
- Fill it. Headspace is somewhere for dissolved ozone to escape into. A full bottle keeps better than a half-empty one.
- Cold and dark. Both slow ozone decomposition. A fridge is reasonable here even though it thickens the glycerin.
- Sealed. Also keeps atmospheric moisture out of a liquid that actively wants it.
Label every batch
Since there is nothing to see, records are the only way to know what you have. On the bottle: the date, the glycerin grade and lot, the run time, and anything unusual about the run.
Without that, a batch from six weeks ago is indistinguishable from one made this morning, which is exactly the situation you do not want with a product that fades on a timescale of days.
Making ozonated glycerin · Safety and ventilation · Glassware and tubing