Quick Guide to Metal Water Bottles

We’re assuming you’re one of many consumers who tote reusable metal water bottles in lieu of single-serve disposable or even reusable plastic ones. That’s great for minimizing plastic production and waste, but do you know the mettle of your metal?

Earth911 boiled it down to get a quick handle on the best buy.

Aluminum

Aluminum bottles are lightweight and tend to be less expensive than steel ones, but require a lining to be food safe, which poses health questions.

Eco- and health-conscious shoppers cried foul a few years ago when aluminum water bottle maker Sigg kept mum about the BPA-laced epoxy that lined its older products.

Although Sigg switched to a new liner that the century-old company says is BPA- and phthalate-free (and today nearly every manufacture of aluminum bottles claims a BPA-free lining), scientists say it’s unclear if the new chemicals used instead are safe.

Under current law, the EPA does not require chemical companies to demonstrate the safety of their products before using them in the marketplace.

Liners can also flake or peel after time, exposing the aluminum interior.

But perhaps less well known is the toll aluminum mining and production takes on the planet at 7.5 kw-hours per virgin pound. U.S. aluminum products contain about a third recycled content.

READ: How to Recycle a Metal Water Bottle

Stainless Steel

Stainless steel bottles are marginally heavier and pricier than aluminum ones, but need no lining. Steel is also stronger and harder than aluminum, which means the bottles better resist denting or other damage.

Stainless steel wins on at least one resource front, too: new stainless steel contains 65 percent to 80 percent recycled steel, about 40 percent of which is post-consumer.

Bottle Tops and Caps

Things get a bit trickier here because most caps contain plastic. Some stainless steel bottle manufacturers offer tops that are mostly metal – certainly the parts that come into contact with drinking water – while the very tip top cap is plastic.

Overall, look for caps made with high grade polypropylene, a stable, durable plastic considered safe (as well as recyclable). If it’s a sport top, be sure the soft tip or any other flexible bit is high grade silicone, a nontoxic material that’s food safe and used in medical instruments. Reusable straws made with high density polyethylene (HDPE) get the OK, too.

READ: How to Recycle Your Bottle Caps

For a useful side-by-side comparison of bottles, check out this chart from retailer REI.