The best way to store essential oils

Our aim is to offer customers products with exceptional quality such that the ingredients, naturalness, potency, storage life and other important quality criteria are maintained over an extended period of time.

Comparable glass and packaging materials limit this requirement as they are not sufficiently able to protect sensitive products from the quality lessening influences of light.

Over the last few years, several scientific tests have been carried out with almond oil, spirulina algae, rose water, drinking water, olive oil, cereals, honey, fruits and other substances to see what protective quality violet glass offers. One such study on Light Absorption by Various Bottle Glass conducted at the Monmouth College comparing amber or brown glass, clear glass, cobalt blue and green glass concluded that the darker the glass, the better at filtering out the damaging UV from high energy light.

A few examples of how violet glass offers better protection than amber glass or clear glass are below.

Storage test with chives

Sprayed-, white-, green- and brown glass are permeable in the visible light spectrum and don’t offer enough protection against decomposition caused by light. As an experiment, several herbs and spices were stored for 3 months in several types of glass (white, brown, violet), and were either exposed to the sun for several hours a day or kept inside. 

Best glass bottles for UV Exposure

After 2 months, the visible quality change was recorded with photographs, and the difference in smell determined in a blind test with volunteers. The illustration shows clearly that the chive samples that were exposed to the sun have bleached in brown and white glass. As photographed in this illustration, the sample stored in violet glass shows no color change. The smell of the chives stored in violet glass was also clearly stronger and fresher.

Storage test with tomatoes

In order to more easily prove the quality protection given to food stored in violet glass, a microbiological experiment was carried out with cherry tomatoes. During this test, a cherry tomato was stored for 7 months in a white glass and in a violet glass, and then kept at room temperature where sunlight could reach it. The result was photographed after 7 months.  The microbiological changes of the tomato stored in white glass can be clearly seen. The tomato stored in violet glass however shows no loss of color and no signs of drying out.

Best glass packaging for sunlight

Photochemistry and Biophotonics

Light can alter the properties of an essential oil or any other product through a general process referred to as photochemistry; chemistry as a result of light (“photo”). The sun emits visible and invisible light parts. The visible spectrum becomes discernable to our eyes when white light is channeled through a glass prism. At the same time though, light also contains a part which is invisible to our eyes and lies in the radius of electromagnetic wavelengths of infrared and UV-A.

The question arises, what wavelengths of light affect the most? The answer is, the higher the energy of light, the more the potential for damage. Higher energy light has a shorter wavelength; therefore 400 nm light is higher in energy than 500 nm, and 500 nm light is higher in energy than 600 nm, and so on. This result is not unfamiliar to most. When we go outside on a sunny day, we usually apply sunscreen to block the high energy light.

Sunlight enables all plants to grow. If they continue to be exposed to the sun after reaching maturity, the effect of the light changes and accelerates the molecular decaying process. Violet glass works like a natural filter that only lets the sunlight that protects and improves the quality of premium and sensitive substances.

There is a large spectrum of packaging materials available nowadays, of which many are permeable to visible light. The following graphics show to which degree light can penetrate the different materials:

Sunlight UV exposure through glass

Violet glass blocks the complete spectrum of visible light with the exception of the violet part. At the same time, it allows a certain part to be permeable for radiation in the spectral range of UV-A, and infrared light. This unique combination offers optimal protection against the ageing processes that are released by visible light, thus lengthening durability and potency of products.

The MEVEI Experiment

In order to substantiate these advantages, our Chief Product Officer and technicians conducted a series of tests themselves to assess the impact of light on the quality of essential oils over an extended period of time.

Four 30 ml bottles made of different colored glass were selected, filled with 15 ml of Vetiver essential oil and placed on an office window sill with moderate sunlight in the evenings for a period of 24 months, which also happens to be the shelf life for most essential oils on the market. The bottles as pictured below from left to right are (a) Cobalt Blue (b) Clear Glass (c) Brown or Amber and (d) Violet glass. Our product team when evaluating the bottles also wanted to determine the best caps or droppers to be used with the essential oils as part of the luxury product packaging. Varying grades of silicone and rubber droppers were used on each bottle. You can see later in this experiment and in the pictures below that although the silicone dropper in the violet glass bottle performed the best, our team instead chose a far better acrylic cap for the final design and packaging that exceeded our specifications and did not degrade at all over an extended period of time.

(From Left to Right – Cobalt Blue, Clear, Amber and Violet glass)

Best packaging for essential oils

Results

After 24 months, the bottles and the caps were closely examined before being opened. The oil was poured out into clear cups and along with the smell and color, the viscosity and the density of the oil was also observed by the amount of the oil that flowed into the clear cups in 30 seconds. The observations for each bottle are explained below. As is visible above, the two white droppers on the cobalt blue and amber bottles and made of natural rubber were visibly damaged by the end of the 12-month testing period due to the volatile compounds in the vetiver oil, oxidation and further degradation in the chemical composition of the oil affected by the sunlight. The black natural rubber dropper in the clear glass bottle, although not visible, showed degradation and minor cracking in the rubber as well. The vetiver essential oil in the clear glass bottle degraded the fastest and had almost solidified within the first 6 months. As a result, the oil was not able to seep up into the dropper due to capillary action and preventing the rubber in the black dropper from extensive decay. This can also be verified from the clear dropper tube inside the clear glass bottle in the image above indicating the absence of any oil in the glass tube. Whereas the oil, able to maintain its viscosity and integrity longer in other bottles, was able to seep up into the droppers and cause extreme damage to the dropper caps, effectively rendering them useless. Only the silicone dropper in the violet glass lasted the duration without any significant or visible degradation. 

(Closeup of rubber dropper on the cobalt blue bottle)

Droppers for essential oils are bad 

Cobalt Blue Bottle: After 24 months, the vetiver oil in the cobalt blue bottle was observed to have become dense, think and more viscous. It had a rancid smell and the color had turned lighter. The oil was sticking all around the glass dropper tube and did not flow very easily, consistently or smoothly. The cobalt blue bottle ranked second to last in terms of being able to maintain the integrity of its contents as per our observations.

Cobalt blue bottles for essential oils are bad

Clear Glass Bottle: The clear glass bottle performed the worst in our experiment and degradation of its content was visible as early as 6 months. After 24 months, the vetiver oil had almost solidified and resembled a thick jelly like gunk. The color had turned to a reddish-brown shade.There was no smell or odor, we believe because the oil had been left exposed to degradation for such an extended period of time that any odor even if rancid or putrid had dissipated in 2 years. The accelerated decay is also evident from the absence of any oil in the glass dropper tube, which also helped prevent any degradation of the rubber dropper bulb from any direct interaction with the oil. It was extremely difficult to pour the contents out of the bottle in the 30 second pour test. 

clear glass bottles for essential oils are bad

Amber Glass Bottle: The Amber glass bottle ranked second in our experiment. The color of the oil was observed to be slightly lighter than the original but darker than one in the cobalt blue bottle. The smell was slightly off and weaker than the characteristic woody, earthy smell of vetiver. In terms of viscosity, the oil had turned thicker and more viscous but did flow more readily and with some consistency compared to the oils in the cobalt blue and clear glass bottles. The increased viscosity and density is also evident from the oil sticking to the glass tube of the dropper. 

Amber brown glass bottles for essential oils are bad

Violet Glass Bottle:By far, the violet glass bottle met and exceeded our expectations with respect to its ability in maintaining the purity and integrity of its content. The color of the oil was close to the original vetiver oil, as observed with the naked eye. It still retained a reddish golden hue. The smell and texture of the oil when rubbed between fingers approximated fresh vetiver oil. It flowed very smoothly and with a consistency similar to a fresh batch of vetiver oil. The most amount of oil poured and collected in 30 seconds was from the violet glass bottle, as also pictured in the comparison image below. No oil was observed to be sticking to the glass dropper tube and despite two years of exposure, the oil could still be used with the dropper. 

Violet glass bottles for essential oils are best

Summary

Side by side comparisons below show the differences in the color, density, viscosity and the amount of oil poured and collected in 30 seconds from each bottle. While the amber or brown glass bottles, widely used to store essential oils came in a close second, it is potentially not the most optimum material for extended long term storage. The violet glass performed the best in our tests in its ability to maintain the freshness, natural ness, integrity, purity and quality of its contents. It was able to block the complete spectrum of visible light with the exception of the violet part while allowing it to be permeated by UV-A and infrared light. This unique combination offers optimal protection against the ageing processes that are released by visible light, thus lengthening durability and potency of products.

Best bottles for storing essential oils

(click on images for higher resolution images)

Best glass bottles for packaging essential oils

MEVEI Violet Glass - the perfect packaging for luxury essential oils

A definite conclusion is that the essential oils stored in violet glass doesn’t break down its ingredients, but actually conserves the smell, color, structure and enzymes considerably better than in any other receptacles known or used until now.

Our signature patented European violet glass bottles offer the greatest degree of protection from the damaging UV rays. Timeless and protective qualities of violet glass are traceable back to the ancient Egyptian civilization, when valuable essences and healing elixirs were kept in gold and violet glass containers. Even the alchemists during the middle ages were aware of the special quality the shimmering violet glass had.

The unparalleled quality of our bottles ensures freshness and gives our oil an extended lifespan. Like a fine wine, some oils age gracefully when encased in violet glass walls.

The elegant character of our packaging makes for a memorable gift or a splendid self-indulgence. We take great pride in the outstanding service we provide to our customers and admirers. The extra mile we go during our creation process ensures an exceptional experience every time.

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