We have received questions from customers asking why we use glass bottles instead of plastic ones? Although consumers typically agree using glass bottles is a good thing. We decided to make this blog post to go over exactly why glass bottles are a better alternative to plastic bottles.
At first glance, plastic bottles seems like a better option for packaging e-liquid. It is cheaper to produce, cheaper to ship, and more widely available. It is also easier to dispense e-liquid from plastic bottles since all you need to do is squeeze your juice straight out of the bottle. But that is where the benefits end.
Besides looking more professional, there are a lot of practical reasons to buy e-liquid packaged in glass bottles: they hold flavor better, juice stays fresh longer, the bottles are safer, more environmentally friendly, and the contents are more chemically stable in glass. I will elaborate each of these points.
1. Flavor Holding Ability
The main factor that makes glass better than plastic is the flavor. Plastic is porous whereas glass is not, meaning that if you observe a piece of plastic under a microscope you will notice it is covered in tiny holes. As your juice sits around, certain flavor molecules are prone to becoming trapped in the plastic, a process known as adsorption. Depending on the flavor molecule and the type of plastic used, the adsorption effect can range from minor to extreme. Conversely, in glass bottles, adsorption of flavor is a non-issue. Here is a link to a comprehensive study that goes over exactly which compounds adsorb most in which plastics.
2. Longer Shelf Life
So, now you know that plastics are porous and that some of your flavors might get lost into the packaging. Big deal, right? There are still plenty of flavor molecules left to make the juice taste good, so what does it matter?
Well, flavor getting adsorbed into the plastic is actually not the only problem that occurs from using materials with all those tiny holes. Polyethylene, one of the most common plastics used in bottling e-liquid, is so porous that it actually “breathes.” Oxygen and water from the air can actually pass through this type of plastic and over time (in as little as a couple weeks) cause unwanted chemical reactions to occur that break down flavor molecules and propylene glycol (vegetable glycerin is actually pretty stable to all this).
Propylene glycol is hygroscopic, meaning that it has the ability to absorb water from the air, diluting the juice. To some consumers, this is not a particularly concerning issue. However, according to DOW chemical, the oxygen in the air will also cause the slow transformation of propylene glycol into lactic acid, a process sped up by any nicotine present since it is an organic base. You might know lactic acid as the compound that makes muscles sore after a good workout, or as the compound that gives spoiled milk a sour taste. While the lactic acid created in plastic bottles is not dangerously toxic, I cannot imagine it would be pleasant to vape.
Similarly, flavor molecules break down over time when exposed to oxygen. A large percentage of flavor compounds are classified as esters or aldehydes and these break down similarly into different acids. For example, amyl acetate is an ester and well-known flavor compound that smells and tastes like banana. Over time this compound breaks down into acetic acid (found in vinegar) and isoamyl alcohol, both of which cause respiratory irritation and would definitely not taste good.
3. Safety First
Let me be clear here: you should always store your e-liquid well out of reach of children and pets. This should not be an issue for responsible consumers, but there are cases where a pet can happen upon a bottle of e-liquid and mistake it for food or a toy. There are not statistics available on e-liquid poisonings as it concerns the packaging materials from research I have conducted, so please let us know if you can find any. Despite this, I will share with you a personal experience I had concerning this topic.
About a year ago I had a friend whose 24 mg e-liquid slipped out his pocket and got lost in my couch. I do not remember the brand but it was right around the time we were starting Om Vapors and had already begun using glass bottles for our juice. About a week after it was lost, my dog found the peachy smelling plastic bottle without my fiancee or me realizing this. My fiancee ran an errand as the dog found the plastic bottle and my dog began chewing it at some point during the 30 minutes she was away. When she arrived home, my dog was seizing on the floor and foaming at the mouth. It was a terrifying ordeal and I hope no one ever has to go through something like that with their furry BFF. Luckily, we have a 24 hour ER for pets in Lexington and we managed to get her there in time for them to treat her. She has been fine ever since.
So, while I do not have scientifically verified safety information as it pertains to my anecdote, I will lay out a little common sense. Dogs have very sensitive noses, plastic bottles start smelling like their contents over time (they are porous) whereas glass ones do not, a large percentage of child and dog toys are plastic, but never glass, and almost any human or animal can puncture a plastic bottle with their teeth, but few can do that to a glass one (in fact, there might be a job for you in show-business if you can). I really believe that if this friend of mine had a glass bottle of e-liquid in his pocket that day I could’ve saved myself a lot of heartache, worry, and a thousand dollars in vet bills.
4. More Environmentally Friendly
It is no secret that plastic is bad for the environment. Just look as these statistics from ecowatch and you can see it is one of the many man-made things destroying our environment. Glass takes about 1/9th the energy to produce compared to plastic, according to this overview by the Australian government. Glass can be recycled indefinitely but plastic can only be recycled to an extent. Since glass is chemically stable it can just be broken down and turned back into differently shaped glass (saving 40% of the energy over freshly made glass in the process). Plastic, on the other hand, can usually only be recycled into post-consumer plastic used in building materials. Also, since plastic breaks down over time, any of it that gets into the environment is going to slowly release compounds with varying toxicity levels depending on the type of plastic and which plant or animal absorbs it. Glass simply sits in the environment and releases no pollutants.
5. Chemical Stability
So, you already know that glass breaks down into, well, glass. What about plastics? What exactly do these break down into and should you be worried about them? Luckily, the majorly toxic plastics like PVC and polycarbonate that can release chemicals like phthalates and BPA are not usually used to bottle e-liquid. Polyethylene (PE, LDPE, HDPE) is very chemically stable and if you have to buy juice that comes in a plastic bottle this would be the one to go for. PET, which is found in the clear plastic bottles you find a lot of cheap e-liquid in, does not quite share this safety profile. PET uses antimony as a catalyst in its production and after it is made traces of antimony are still in the plastic and over time it slowly leeches out. Chronic exposure to antimony, according to the EPA, can lead to such wonderful side effects as alterations in pulmonary function, chronic bronchitis, chronic emphysema, inactive tuberculosis, pleural adhesions, and irritation. Since e-liquids are a product that is inhaled rather than injested, users are exposing the very sensitive cells in their lungs to these harmful chemicals. In all fairness, the leeching of antimony from PET is a slow process and the amounts are low. I have not found a case of it being detected in a commercial e-liquid, but the risk is definitely out there.
So, is e-liquid stored in a plastic container the worst thing you will ever put in your body? Probably not (definitely not if you have used cigarettes), but I think there are plenty of reasons to choose glass when you have the chance. We do not ever plan on using plastic bottles in our product line due to the aforementioned reasons. If you have any questions or comments, feel free to leave a comment here or on Facebook. We are always happy to discuss the safety and risks involved with all things e-cig related.