How Does Copper Insulation Work to Keep Your Drinks the Perfect Temperature?

Understanding temperature Conduction

Heat conduction occurs due to the law of Thermodynamics.

In a nutshell, heat energy always seeks equilibrium. Any hot particles will eventually transfer some of their heat to colder particles nearby, so that when enough time passes, the exact same temperature is found everywhere.

This concept can be demonstrated when you touch a cup that's holding a hot or cold drink. Metal, compared to other materials like ceramics, is an extremely good heat conductor.

Ever noticed how when you pick up a metallic object - say, a metal fork or spoon - that the surface feels cold to the touch? Even more so than picking up a ceramic equivalent?

That’s because the atoms in the metal draw heat away from your fingers, making your fingertips feel colder.

how does the beast benefit from Copper Lining?

Because of this natural temperature conduction phenomenon, copper layers are incorporated into the inner portion of the tumbler's lining. The conducting copper layer is sandwiched within the void of the double-wall vacuum insulation. This provides a one-two punch of heat and cold retention.

When we line the BEAST's double-walled vacuum insulation with copper lining, external temperatures trying to wreak havoc on your beverage just don't stand a chance!

Whether it's an icy cold or a steamy hot drink you're putting in your BEAST, the copper lining works powerfully in both cases to keep the temperature stable.

It goes to work drawing any heat toward it, which works in two ways to retain both ends of the temperature spectrum:


External warmth from the atmosphere is drawn in and trapped inside the copper layer that's sandwiched between the double walls.

This prevents any heat from your outside world from making contact with the stainless steel interior that the liquid touches! Your ice won't melt and your drink will stay perfectly chilled.


Radiant heat from your hot beverage is attracted to the copper layer on the inside of the double walls. The copper warms up, keeping your drink wrapped in a cocoon of cozy warmth.

This trapped heat can't escape to the outermost layers where it can eventually bleed away into the environment, which would gradually decrease the temperature of your beverage.

Is Copper actually Safe for drinkware?

Yes! Properly made drinkware that utilizes copper in the construction is completely safe to drink out of.

We only use copper on the inside layers here at Greens Steel however... Even though you do see some cups made entirely of copper, and that's ok too. (Remember that Moscow Mule mug?)

The reason why we keep the copper on the inner layer of the BEAST is because copper can often produce a slightly “tinny” taste to beverages.

By wedging the copper inside the double-wall vacuum layer, it allows you to enjoy the benefits of the copper lining without compromising on taste!

Your drink will never come into contact with anything other than pure, food-grade 18/8 stainless steel. This combo of perfectly pure taste and unparalleled insulation means the BEAST will see you through years' worth of delicious beverages at the ideal temperature.

Ultimately, copper insulation is just one way that we here at Greens Steel aim to reinvent the industry.

We’re dedicated to innovation, always looking for new and advanced ways to make your experience one for the books. We pride ourselves on providing travelers and drinkware enthusiasts top quality products that consistently outperform their competitors on both function and price!

Try our BEAST Tumbler today to see just how thermally-friendly copper lining can be on your ultimate drinkware...

Justin | Greens Steel BEAST fan

Sheffield, UK


Copper lining is where it’s at. The BEAST wins the cup at keeping your drink just the temperature it’s intended to be.  Check it out…