Hi — I sometimes buy incense that comes with a lightly dyed plaster disc holder. Because of plaster’s absorbency, I use these holders as essential oil diffusers. Is that appropriate?
I’d also like to know if you would recommend any of the commercially available oven bake clays to make terracotta-like diffusers. I’m concerned about absorbency. I’m also thinking that maybe regular clay baked at low temperature for a long time could also work.
Thank you very much for your help.
The diffusion of vapourizing essential oils into a room can have numerous effects – from the pleasure of how the odour molecules stimulate one’s senses to the therapeutic treatment of respiratory conditions. There are a number of methods or tools to enable diffusion, passive diffusers being one of the simplest and least expensive.
The most common passive diffusers available in the retail market are made of terra cotta or baked clay. Due to the passive nature and the limited area of diffusion, these diffusers are least effective for the therapeutic treatment of respiratory conditions. They are primarily used for creating an aromatic environment in small areas such as a bathroom, closet, drawers and the car. [DUE DILIGENCE is required when choosing essential oils for diffusion in an operating vehicle!]
On the subject of using Plaster of Paris discs as a passive diffuser verses using baked clay or terra cotta discs, I suggest using clay or terra cotta which means “baked earth”. Plaster of Paris is primarily made up of gypsum, sand and water and remains soft enough to be sanded and carved. It is extremely porous and research shows that there is an exothermic chemical reaction when water is mixed with plaster. That is to say that when the plaster molecules bond with water molecules heat is produced. This fact alone is enough to question the application of essential oils onto unglazed plaster. Terra cotta is a mixture of finely ground red and buff clays with ground fired clay called “grog” which gives it stability. It is semi-permeable to air and water and has been used since ancient times for pottery which I find synergistic with essential oils, the origins of which also date back thousands of years. To get mileage out of the incense aroma on the plaster discs, consider placing them in a stationary drawer, in a suitcase before packing or in a jewelry box with your favourite necklace or earrings.
I am not experienced with the commercially available oven bake clays so cannot make a recommendation. The advantage of kiln baked clay is that the intense heat evaporates the clay’s water leaving space for the essential oils to be absorbed. I understand that oven baked clays cannot withstand liquid but I have not been able to determine if that means it is semi-permeable when dried, like terra cotta. I think it would be worth experimenting but ensure that the oven bake clay you choose has a non-toxic label on it. I’d love to know the results!
Barbara Power, Certified Aromatherapist