Chapter 1
The great global coffee migration
Chapter 2
The secret botany of the coffee cherry
Chapter 3
The fiery chemistry of roasting
Chapter 4
The physics and art of extraction
YOUR GOAL
Master of From wild forests to the perfect pour
Ch 4 · The physics and art of extraction
sonia The Physics of Coffee Extraction
Acids first, then sweet! Acids first, then sweet! Bitters are the last to meet.
Fun Fact
Espresso pressure: An espresso machine uses 9 bars of pressure, which is equivalent to nine times the atmospheric pressure at sea level.
Glossary
extraction (noun)
The action of removing or obtaining something from a substance, especially by effort or force. In 1957, biochemist Ernest Lockhart developed the Brewing Control Chart to map optimal coffee extraction yields.
The action of removing or obtaining something from a substance, especially by effort or force. In 1957, biochemist Ernest Lockhart developed the Brewing Control Chart to map optimal coffee extraction yields.
Quiz
What is the widely accepted standard water-to-coffee ratio used by professional specialty brewers?
Quiz
Which minerals dissolved in brewing water act as 'chemical claws' to extract flavor from coffee grounds?
Quiz
What is the golden, creamy foam layer that sits on top of a freshly pulled shot of espresso?
Quiz
If your brewed coffee tastes overly sour and weak, what extraction issue has likely occurred?
Quiz
Which brewing method requires a very coarse grind size to prevent over-extraction during a long steep time?
Quiz
What is the standard atmospheric pressure used by commercial espresso machines to extract coffee?
Quiz
What percentage of a standard cup of brewed specialty coffee is actually made of water?