Well just as you can see that dark to light transition occur early in the shot what you want to look for is the white fluffy crema to begin getting streaks of more 'liquidy' (tm) streamers into that same flow. So Dark, Light, and then you pick to some where in the stripe area, and just to piss you off some coffee's are better with more stripe, and some with none.
Everyone recite with me. The taste in the cup is what tells.
Thanks Erudoph.
Catch ya later.




