Mädchen gießt Kaffee aus Thermosflasche in Becher


A bottle to go

A vacuum between two containers – that sounds as simple as it is ingenious. The idea came to glass technician Reinhold Burger in the early 20th century. Those who drink coffee on the go still use it today: the thermos flask.

How can cold liquefied air of minus 194.5 degrees be stored and transported? This was the question on the mind of ice machine manufacturer Carl von Linde in the early 20th century. He tasked glass technician Reinhold Burger from Glashütte in Brandenburg with developing a container.

In 1894, Burger had started a company in Berlin to manufacture glass instruments and laboratory equipment. To fulfil Linde’s order, he experimented with double-walled, mirrored glass flasks with a vacuum between the two outer cases to serve as insulation. As a transport container, however, the design was too fragile. So Burger experimented further – and used hot water for his experiments. “That’s when it occurred to me that I could use beverages instead.” The basic idea of the thermos flask was born. It was some time before the idea could become reality, however. The neck of the bottle was still unstable in the early days and broke off when the liquid was poured out. So Burger stabilized the double-walled glass vessel on the inside using asbestos plates attached to wire. Applying a special method, he also managed to make the inner silver coating permanently durable. And he gave the bottle a cork, a drinking cup, and a metal casing. Step by step, his idea became suitable for everyday use – and, as he promised, “indispensable for tourists, travelers, drivers, cyclists, water sports, military, airmen, forestry officials, hunters, and the office”.

On October 1, 1903, Reinhold Burger had his thermos flask patented at the Imperial Patent Office. Three years later, he founded the company “Thermos-Gesellschaft” in Berlin. As sales were slow at first, he transferred the foreign rights over to the American Thermos Bottle Company in New York in 1909, which sold the handy insulated containers in many countries. This is how the invention from Brandenburg made its way out into the world – and it is still popular today, be it with hikers, construction workers, or students.

(Header: Maria Savenko - Shutterstock)

Zeichnung der Thermoskanne aus der Patentanmeldung
from the patent application

Place of invention

R. Burger & Co., Chaussestraße 8, Berlin