Why it matters in the cup.
Coffee glossary
Crema
The layer of foam formed when gases and emulsified coffee oils emerge under espresso pressure.
Filed under
What you see in the shot
What you see in the shot
What it means
The layer of foam formed when gases and emulsified coffee oils emerge under espresso pressure. It influences aroma delivery and presentation and can indicate freshness, but thick crema alone does not prove the shot underneath is balanced or well made.
Keep going
Where this leads
Each one pushes this into the cup, compares it, or helps you act on it.
What people mean when they say "extraction"
Espresso Extraction
Read the visual cue through extraction, not appearance alone.
Separate extraction from strength in your thinking. One asks how much was dissolved, the other how concentrated the drink feels.
How you read the result
Yield
Tie what you see to what actually lands in the cup.
Think of yield as the result you are aiming for and brewed weight as the way you verify you hit it.
How you read the result
Brew Time
Visual changes often show up before the timer becomes meaningful.
Use time as a guide rail alongside yield and taste, not as the whole recipe.
What people mean when they say "extraction"
Espresso Strength
A pretty shot can still feel thin or too dense.
Use the word strength carefully. It describes concentration, not quality.