This is the new, enlarged and improved model of our favorite line of little workhorse roasters, the FreshRoasts, the most popular home coffee roaster with over 100,000 units sold worldwide. It is sturdier and roasts a tad more, with a much larger roast chamber than its predecessor the SR500. Using four scoops (provided) of green coffee, this roaster will generate about 4.2oz of roasted coffee, which using our recommended coffee to water ratio comes out to 72oz of brewed coffee (or 12 6-oz cups). It is more versatile that its predecessor, the SR500. It has an improved control board. For us the main advantage of this fluid-bed roaster is its ability to roast variable amounts of green coffee from one scoop (43 cc) to four scoops (the equivalent of 4.6 ounces, or 130 grams, unlike larger, more expensive roasters that force you to roast always the same amount of coffee. We use it as a handy and portable sample roaster.This roaster is made in China. With the SR540 you can vary the length of the roast time, the temperature of the roast (9 settings, versus the three of the SR500) and the fan speed (a turning knob) has a wider range than before. All adjustments are made with pushing the knob and turning to adjust the heat, fan, and time. It also features a real-time temperature read out. A quick turn of the knob to the right will display current temperature. However you need to "play around and get the feel" of your new roaster to learn how to use the new features. For example, if you set the fan on high and agitate the beans to briskly, the chamber will never get hot enough and your beans will not roast; they will just bake, which is something you do not want to do. The chaff basket and top lid from earlier SR roasters will not fit on the new SR540. The roasting chamber is a much larger diameter. Users are also able to change the default start settings.