So, what types of water bottles are actually the safest to use?  In the world of big water bottles, brands are always looking for ways to differentiate and stand out.  This includes using different types of materials like copper, stainless steel, and even titanium.  Some are safer than others, so let's take a look at eight of the most common water bottle materials to learn about historical issues and what the current science says.

If you're new to the channel/blog, welcome!

​At the bottom is copper.  This material has a very long history, particularly related to Ayurveda and in regions and countries like India.

​Next is plastic, which is the most commonly used material in water bottles worldwide.  Some of the biggest brands include Nalgene, Camelbak's Eddy bottles, and YETI's Yonder series.  However, plastic has a spotty safety record primarily due to leaching.

Back in the early 2000s, bisphenol-A chemicals, also known as BPAs, were all in the news.  These are commonly used in many plastics including popular water bottles at the time.  But studies found negative effects primarily related to hormone disruption after longer term cumulative use.  That's why every bottle on the market today is BPA-free, and bottles have shifted to alternative formulations.

However there are a growing number of studies like this one that indicate potential issues with BPA replacements like BPS and BPF, and other chemicals like phthalates come with their own concerns.

It's worth noting that "plastics" is a HUGE category, and most studies today show that many plastic types that are classified as food-safe are OK for regular use in contact with food and water.

​But given the poor history and current uncertainty around many of the chemicals used in its construction, there is a growing number of people who are choosing to avoid plastic as much possible by picking bottles that limit plastic contact with their drink or mouth.  That's enough for me to rank plastics a little lower.​

Next up we have aluminum, and probably the biggest name within this category is Sigg, the big bottle manufacturer based in Switzerland.  I ranked aluminum fairly low for a reason you might not expect because in reality, it's effectively more like a plastic bottle.

Aluminum naturally reacts with air to create a protective oxide layer on the outside.  However, it doesn't really take much to disrupt that oxide layer, either through physical damage, or with a salty or basic solution.  You can increase the thickness of this protective layer through a process called anodizing, but that usually just applies to the outside of the bottle, leaving the inside susceptible to corrosion from the liquid inside.

That's why every aluminum can and bottle I'm aware of on the market has a plastic lining on the inside, and I recently did an experiment to show you that lining that you can see in this video.

A similar lining is also included on the inside of paper cups and aluminum cans.

​Next is silicone.  These bottles aren't quite as popular as other ones like plastic or stainless steel, but you can still find a decent number of options like this one, particularly in niches like hiking because they're lightweight, durable, and packable.

Most studies and references I've seen point to the fact that food-grade silicone is safe for regular use.  It has a lot of similarities to plastic, but plastic is petroleum-based compared to silicone which is silica-based.  Silica is what you find in something like quartz sand and is also used to make glass, and it has fewer chemicals and toxicity concerns like you find with petroleum product used to make plastic.

But it's still a very synthesized material that's being studied more and more, so many people are understandably worried that studies might come out later showing health impacts much like what happened with BPAs and plastic.

Silicone is also fairly notorious for holding onto odors longer than other materials, though that isn't necessarily an indication that the bottle is unsafe.

​Next is ceramic.  To clarify, we're not looking at traditional ceramics like you'd find with coffee mugs because those aren't really used that often for water.  But you certainly could, and there are some places where you can buy something like a tumbler with traditional ceramic construction, though sometimes you might need to get it from a local ceramicist.  The main thing to check on there is if the glaze and ceramics are free of lead and cadmium, and if you're good on those then you should be safe.

Instead, our main focus is instead with ceramic linings.

​Next up is titanium, which is non-reactive and safe in most applications and that's why you even see it used in things like medical and dental implants where material safety is really important.  Also, titanium is more resistant to corrosion than aluminum, so you don't need a plastic coating.

That all translates to titanium looking like a safe option for a water bottle material based on the information I found in articles like this (which mentions there are potentially some issues, but it's very rare).

Though it's worth noting that because it's still a relatively new material for use in water bottles, there aren't that many scientific studies yet compared to other materials like plastic.

​Next is stainless steel, which is what you find with most of the viral and popular water bottles today like YETI Ramblers, Stanley Quenchers, and Owalas.  Stainless steel is very safe and widely used in food preparation and other food contact uses, which makes it a great choice for water bottles.

​It comes in several different grades that can be confusing, and you'll often see terms like 304 or 316, along with 18/8 or 18/10 thrown around.  These terms reference the chemical composition, for example 18/8 has 18% chromium and 8% nickel.  Some grades are technically safer or more resistant to corrosion than others, so if you want the highest quality steel possible go with a bottle made with 316 or 18/10.  But honestly, any of these stainless steel classifications should be safe for use as a water bottle.

​Here's a link to an article that goes into even more detail if you'd like to learn more about the different grades of steel.

And last but not least is glass.  This is widely regarded as being possibly the purest and safest choice in terms of leaching because it avoids metals, chemicals, and other questionable additives like you find with something like plastic.

Now you might have noticed I didn't rank anything in the top tier, and that's intentional.

Most bottles use a combination of materials, like glass bottles having plastic lids and just about every bottle using silicone seals.  So in reality, almost every bottle you buy can realistically come with some risk, or at the very least some components that might be worth keeping an eye on in case science and studies come out with new information.

​That's not intended to scare you because most of the bottles on the market are probably perfectly safe assuming you use and maintain them properly.  And either way drinking water more regularly and improving your hydration is still one of the best things you can do for your health.

While picking the right water bottle is an important choice, unfortunately there are other contaminants like microplastics and PFAS that existing almost everywhere in the environment, including many people's water supplies.

If you haven't heard of PFAS yet, here's my deep dive into that topic.  Long-story-short, they are chemicals that last a very long time (aka "forever chemicals") and have been linked to health issues to the point that several major lawsuits have been awarded against key offenders, including this one for over $10 BILLION with 3M.

Very few bottles have filters capable of removing something as small as PFAS, but GRAYL's GeoPress is one that has tests to back it up.

And for microplastics, there is a lot of evidence that these particles exist in A LOT of places already.  But given that the majority of bottles contain plastic lids and threads, there are a growing number of people actively looking for bottles that reduce plastic use and contact with their drink or mouth.

And finally, the biggest health risk overall in my opinion isn't the material type or contaminants like PFAS or microplastics.  Instead, the biggest risk is not cleaning your bottle regularly.  Bottles are notorious for hiding germs, mold, and bacteria, so getting on a regular cleaning schedule is really important.

​Check out this post for my recommended best practices and please get in that habit regardless of which bottle you get, including these two accessories I've used for years.

Hope this helps, and happy hydrating!

(10 minute read)

Many supposedly "eco-friendly" cups, cans, and bottles actually use a plastic liner on the inside.  In addition to eventually ending up in landfills and adding to the growing microplastic problem, there are legitimate concerns over whether these plastic liners are healthy with long-term use.

​In this post, we'll take a closer look to learn more about the plastic liners hidden in many common cups, cans, and bottles so you can make a more informed decision.

​If videos are more your thing, check out my Youtube video that covers most of the same information.

There are three types of popular containers that most people consider eco-friendly or plastic-free that actually have a plastic liner hidden on the inside.

At this point the cup looked saturated, but the paper still had a lot of strength to it.  The aluminum bottle looked unchanged.

The Sigg aluminum bottle had started dissolving, but I let it go a few more days.

​So now you've seen the plastic liner on these three containers, and it's a practical and inexpensive way for manufacturers to offer drinks.  But the question is, is it safe?  This is where it gets a little murky.

It's worth noting that all of the plastic liners you've seen in this video are classified as food safe.  However, plastic containers have a long, troubled history with our health, usually after research over decades indicates that certain chemicals commonly used in plastics can have negative effects on your health.

So what can you do?

When it comes to disposable paper cups and aluminum cans, it's best to avoid them as much as possible.  You could recycle them, but the inefficiencies and issues with recycling programs in general could be the topic of a much longer post.  The sad fact is that many things we think are recycled end up just being thrown away.

Case in point, the Subway where I got the cup for this experiment has the typical trash can near the door that's inside a cabinet.  There are two holes on top, one for trash and one for recycling.  But if you look inside, both holes drop into the same trash bin.

The best options that avoid plastic liners are stainless steel and glass bottles.

​No stainless steel bottles I'm aware of have a plastic liner, so going with popular brands like Owala, YETI, Stanley, or Hydro Flask is a great option.  Unless you have a nickel allergy, it's a really safe bet.

Glass does not contain plastic at all, and there are a bunch of those to choose from including Lifefactory, Ello, and W&P Porter.

Unfortunately, this seems to be a growing sub-product niche that hasn't gone mainstream yet, and I've seen quite a few brands and options with stainless steel under the lid that have come-and-gone.  Some of the links above were out of stock when I wrote this article, but I'm hoping they'll be back in stock soon so I still left the links in so you can check them yourself.

​Hope this helps, and happy hydrating!

If you have not heard of microplastics in the past, the National Oceanic and Atmospheric Administration gives a quick recap here. (or just google "what are microplastics" and it should come up near the top of the list).

Essentially, microplastics are small pieces of plastics that are less than 5 millimeters long.  They are caused when small plastics are washed away or discarded, and they can also be created when larger plastics break down over time.  The widespread use of plastics combined with the difficult of filtering these small pieces has caused to them to become increasingly prevalent and widespread in our drinking water, lakes, and oceans.

And as you might expect, nanoplastics are similare but are even smaller.

Some microplastics with common examples include:

• polystyrene
  • foam-forms like in insulating coolers and cups, as well as packing peanuts
  • hard forms include items like some disposable razors and CD cases
• polyethylene (the most commonly produced plastic)
  • "HDPE" (high-density polyethylene) is used to make many common containers, like milk jugs and detergent bottles, as well as industrial-size products like municipal water lines
  • microbeads that are used as exfoliants in some health and beauty products, which were thankfully banned as part of the Microbead-Free Waters Act of 2015)
• polypropylene (2nd most commonly produced plastic)
  • found in many food-grade products (including many water bottle lids)
  • some clothing (though polyester has become a common replacement)

The experiment is titled "Drinking Boiled Tap Water Reduces Human Intake of Nanoplastics and Microplastics." According the the abstract, the authors claim to:

"present evidenence that polystyrene, polyethylene, and polypropylene NMPs can coprecipitate with calcium carbonate (CaCO3) incrustants in tap water upon boiling. Boiling hard water (>120 mg L–1 of CaCO3) can remove at least 80% of polystyrene, polyethylene, and polypropylene NMPs size between 0.1 and 150 μm. Elevated temperatures promote CaCO3 nucleation on NMPs, resulting in the encapsulation and aggregation of NMPs within CaCO3 incrustants."

Essentially, this means that boiling water causes the plastics to combine with calcium cabonate (aka the "hard" in "hard water" that is in most people's homes), then the combined particles then drop to the bottom, leaving a layer of cleaner water on top.

I do not have full access to the article, but I would expect two followup questions should be considered that weren't covered in the abstract.

1. Does the water need to be filtered after boiling (likely), and if so, what type of filter would be effective to remove the precipitate?
2. How does this compare to other filtration methods, such as reverse osmosis?

At BottlePro, we keep an eye out for hydration and water bottle news, then we summarize it and post it here.  Check back with us to stay in the loop!