THE ART OF ROASTING @museum.de

The unique coffee aroma and the aromatic flavour of coffee are only created by roasting. Immediately after harvesting, the coffee pips are green and smell of hay or grain.

The art of roasting consists of picking just the right moment to ensure that hundreds of aromatic substances can develop. When that point is reached, the roasting process has to stop, so the little pips don’t become scorched. On the stove top, you can see roasting pans and hand roasters.

In the early days, coffee was roasted in open pans. Then, in the middle of the 17th century, roasting cylinders were developed: closed containers in which the coffee beans could be turned over a fire. The downside was that you couldn’t check to see how the roasting process was coming along. We also have a spherical French roaster from 1806 on display – a legacy from the time when Hamburg was under occupation by Napoleon's army. The green coffee is filled into the spherical container and constantly turned over an open fire. To this day, a French roast is considered a speciality, because the long roasting time results in stronger and more digestible coffee.

For our traditional Burg roast, we turn on the gas and preheat the roaster on the ground floor to about 200 degrees Celsius. The green coffee slips down the hopper into the drum, and while the coffee is kept constantly in motion, the roast master has to keep a close eye on the degree of roasting. After about 15 to 20 minutes, the roaster’s lid is opened and the coffee beans are poured into the cooling sieve to cool. This traditional roasting process allows the coffee to develop 800 aromatic substances, but it loses about 20 per cent of its weight.

The 1970s saw the development of industrial roasting, a rapid process at very high temperatures. It’s carried out at up to 500 degrees Celsius and takes just two minutes. Afterwards, water is used to cool the beans. Industrial roasting has reduced the price of coffee, but the quality has suffered.