How do
double-walled glasses?

A glass in which the coffee seems to float, warm on the inside and cool on the outside. Below, you can read how double-walled glasses work, which drinks they are designed for, what the hole in the base does, how to wash them, and why water sometimes gets between the walls.

Air between two wallsHot stays hot, cold stays coldHole in the base: normal
Coffee in a double-walled glass
DOUBLE-WALLED ✶ THERMAL GLASS ✶ COFFEE ✶ TEA ✶ GLAZEN.NL ✶

The principle

A double-walled glass is two glasses in one: an inner glass and an outer glass, fused together at the rim, with a layer of air in between. Air is a poor conductor of heat, so the heat from coffee or tea does not reach your hand, and the cold air outside does not reach the drink. This keeps a latte warm for ten to twenty minutes longer and iced tea cold for longer, while preventing condensation on the outside.

The walls are made of borosilicate glass because it can be blown thin and withstands boiling water. Read more in our article about borosilicate glass. The optical effect, making the drink look like it is floating, is a bonus.

Which drinks?

Coffee in all its forms: espresso, cappuccino, latte macchiato, and Irish coffee. Tea, especially loose-leaf tea that you can watch steep. Iced coffee and iced tea, because the ice melts more slowly. Cocktails on ice and whisky also stay cold longer, though double-walled glasses are less common for these drinks.

Less suitable for beer and wine: the rim is thicker than that of a regular glass, and the head or aroma does not come through as well. Find all sizes in our double-walled glasses collection and in our article about coffee glasses.

The hole and the dishwasher

There is a small hole at the bottom of the outer wall, often covered with a silicone plug. It is needed during manufacturing: without a hole, as the glass cools, the air between the walls would suck the glass inward. Water can get between the walls through this hole in the dishwasher. Any drop that remains will evaporate in a few days if you leave the glass upside down.

Therefore, hand-wash double-walled glasses in lukewarm water, or place them upright in the top rack of the dishwasher on a low setting. Do not soak them, put them in the microwave, or try to get between the walls with a stiff brush. A glass with a crack in the outer wall is no longer usable.

The right glass

Luigi Bormioli's Thermic glasses are hand-blown borosilicate. Here are the 34 cl latte macchiato glass and the 22 cl tea glass, both sold in pairs. Find all sizes in the double-walled glasses collection.

Luigi Bormioli Thermic Latte Macchiato Glass 34 cl (2 pieces)
Our pick 01

Luigi Bormioli Thermic Latte Macchiato Glass 34 cl (2 pieces)

€ 24,95per set · fast delivery on business days
Luigi Bormioli Thermic Tea Glass 22 cl (2 pieces)
Our pick 02

Luigi Bormioli Thermic Tea Glass 22 cl (2 pieces)

€ 22,95per set · fast delivery on business days

Good to know

Can you pour boiling water into a double-walled glass?

Yes. Borosilicate can withstand boiling water poured directly into it. Don't put the glass on a hot plate or in the microwave.

There's water between the walls. Is the glass broken?

No, it got in through the hole in the bottom. Leave it upside down in a warm place and it will evaporate. A crack appears as a line in the glass.

Why is a double-walled glass so light?

Because borosilicate is blown thin. It feels fragile, but withstands heat better than thick regular glass. It's less resistant to impacts.

Frequently asked questions

How does a double-walled glass work?

Two borosilicate walls with air between them. Air insulates, so the drink stays hot or cold longer and the outside stays cool and dry. View our double-walled glasses.

What is the hole in the bottom of a double-walled glass for?

To equalize the air pressure between the walls during manufacturing. It's normal and often covered with a small plug.

Can double-walled glasses go in the dishwasher?

Hand-washing is best. In the dishwasher, place upright on a low-temperature cycle; water can get between the walls through the hole.

Everything for your table,
to one address

Double-walled glasses, sold in sets. Order today, delivered quickly.

Shop double-walled glasses →