to a dark color in small batches at home and by shopkeepers, using a variety of appliances including ones with a rotating cylinder of glass, sheet iron or wire mesh, and ones driven by hand, clockwork or electric motor. Because of the smoke and blowing chaff, country dwellers generally roasted outdoors. In the 1950s just as instant coffee was becoming a popular coffee drink, specialty coffeehouses began opening to cater to the connoisseur, offering a more traditionally brewed beverage. In the 1970s, more specialty coffee houses were founded, ones that offered a variety of roasts and beans from around the world. In the 1980s and 1990s, the gourmet coffee industry experienced great growth. Through the 1970s and 1980s, the Siemens Sirocco home roaster was made in West Germany and marketed globally. It was a small fluid-bed roaster made for the home enthusiast. The product was named after a commercial hot-air roasting process which itself was named after the hot Sahara winds called sirocco. In 1976, chemical engineer Michael Sivetz patented a competing hot air design for manufacture in the U.S.; this became popular as an economical alternative. Sivetz called for the home roaster to focus on the quality of the bean. From 1986 through 1999 there was a surge in the number of patents filed for home roasting appliances. In the 1990s, more electric home roasting equipment became available, including drum roasters, and variations on the fluid-bed roaster. By 2001, gourmet coffee aficionados were using the internet to purchase green estate-grown beans for delivery by mail. Advantages Enjoying coffee made from freshly roasted beans is one of the major driving factors in the popularity of home roasting. Home roasting has the advantage of being able to roast smaller volumes of coffee to match consumption so that the roasted coffee is used before it goes stale. Depending on the bean's origin and the method of storage after roasting, generally whole bean coffee flavor is at its peak between seven and fourteen days after roasting, but some beans are best left even longer, up to 21 days. The flavor of ground coffee deteriorates even faster. Methods of extending freshness include refrigeration, freezing, vacuum packaging, and displacing oxygen in the container with an inert gas. Green coffee beans can be kept fresh for 1–3 years, depending upon storage conditions, and more particular home roasters reduce storage time to 8 or even 1.5 months.