The graphic above illustrates how complex making coffee is. Under extracted coffee is sour, over extracted is bitter. The sweet spot is in between, when you get it just right. But to find that spot, everything moves (ratio, dose, yield, temp, pressure, time, age) all depending on where your coffee is on the 150 points of Roast Level. Measuring your coffee density and using this site, will give you the roast level and all the appropriate settings to get you as close to the sweet spot as possible. You will be making less dramatic moves with your grinder, and you will be able to successfully make a wider range of roast levels of coffee with whatever your chosen method is.
Use this site to make beautiful coffee. Avoid sour and bitter coffee, by finding the Sweet Spot.
A simple density measurement indicates the optimum brew guide; catering for 150 roast levels for espresso and filter methods.