Figure 3: Basic Espresso Machine Heat Exchanger and Hydraulic circuitry (Source: Rancilio Group)
The Inside of the E61 Grouphead
The HG One - Superb coffee grinding in your hands!
Sumatra: Citarasa Klasik Kopi Indonesia?
Coffee roaster - Tìm với Google
What is roasting "Development-Time"? : NEW WAVE Coffee Roasters : 네이버 블로그
cumulative chemical composition of espresso with increasing extraction time (and over extraction)
A simple way to explain various coffee drinks. So many more coffee related photos in this post via darkroastedblend