Below is a table outlining the staining capacities of various popular coffee brewing methods. There haven't been any studies directly quantifying staining with different coffee brews, but I was able to compile this information using a bunch of different research that looked at concentrations of other coffee compounds that correlate well with concentrations of staining compounds.
|Type of Brew||Water to Bean Ratio (by weight)||Grind Size||Extraction Time||Water Temperature (°F)||Staining Concentration|
|Siphon||14.42||Finer than Drip||3 min||202|
|Pour Over||14.82||Sand||2.5 min||200|
|French Press||14.71||Coarse||4 min||195-200|
|Cafe Solo||23.78||Coarse||4 min||200|
|Cold Brew||3.00||Coarse||10-12 hrs||Cold||Least|