Design Explained –
Our Original Vacuum Glass Liners

Last year, we celebrated our centennial anniversary as a company, and with you as our customers, we’ve come so far. Founded in 1918 in Osaka, Japan, our company was founded as the Ichikawa Brothers Trading Company, producing vacuum insulated glass liners for carafes. These glass liners were state-of-the-art in 1918, and remain a proven, innovative technology along with our more modern rice cookers, small appliances and vacuum insulated stainless steel products.

Blowing glass by hand

Glass is a surprising material. We encounter it every day in our drinking vessels, windows, jewelry, art and so on. It seems so commonplace but it’s actually a marvel of science and engineering. In its basic form, glass is made by combining silica – one of the most abundant materials on Earth – with other elements in order to produce a material with unique thermal, optical, chemical, mechanical and electrical properties.

Our vacuum glass liners in the Air Pot® dispensers and carafes are made using medical-grade borosilicate glass. Borosilicate glass is made by adding boric oxide, a form of the element boron. Because of it’s unique chemical composition, borosilicate glass is more resistant to thermal shock than regular soda-lime glass, meaning that it won’t shatter or crack when exposed to sudden temperature change. It’s also clear, moldable and easily cleanable, making it an ideal material for glass liners.

Carafe with a glass liner

To make these glass liners, we first create an outer vessel in the shape and size of the carafe or dispenser, then make an inner vessel, which is placed inside the outer vessel. We then coat the interior of the vacuum wall between the two vessels with silver plating to give it heat reflecting properties. Finally the air between the two vessels is removed to create vacuum insulation, which maintains the temperature of the contents of the inner vessel.

Vacuum Glass Liner

Words don’t do the process justice, so check out our video of how our glass liners are made in our factory in Osaka, Japan.

It’s no wonder that we’ve been obsessed with glass liners for a hundred years. We are proud to manufacture quality products for our customers, using this innovative and wonderful material.

Share your favorite Zojirushi product with us, and let us know if you have one of vacuum insulated glass liner products!

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