A Few Tips to Start
In general, pre-infusion should last between 30 seconds and 1 minute. The amount of water added should be about double the mass of the coffee you plan to brew.
EXTRACTION AND BREWING
In simple terms, extraction is the process of pulling flavor out of your coffee beans. There are hundreds of soluble compounds in every single coffee bean. As your coffee comes into contact with hot water, those compounds are extracted from the non-soluble grounds. The resulting cup is around 98.8% water and 1.2% coffee flavor particles.
There are several factors that will affect the extraction: coffee/water ratio, grind particle size, contact time, coffee bed depth, amount of turbulence and water temperature. Understanding how each of these factors is interrelated to the final product can help troubleshoot and fine tune the brewing process.