Coffee Midterm Review

What do you expect to happen when a coffee brew is subjected to heat over a prolonged period of time?

• pH decreases over time

• pH increases over time

• Acid concentration decreases over time

• Acid concentration increases over time

• pH and acid concentration decrease at the beginning, then increase towards the end

To increase mass transfer of coffee molecules from the solid grounds to the liquid brew, one should:

• Use coarse grinds

• Use fine grinds

• Increase water temperature

• Decrease water temperature

Higher mass transfer of coffee molecules from the solid phase into the liquid phase would result in:

• Higher TDS value of the brew

• Higher PE value of the brew

• Lower TDS value of the brew

• Lower PE value of the brew

How does coffee extraction pressure affect mass transfer of coffee molecules from the solid phase into the liquid phase?

• High pressure leads to high mass transfer

• Low pressure leads to low mass transfer

• High pressure leads to low mass transfer

• Low pressure leads to high mass transfer

Which filter material absorbs oils more easily?

• Paper

• Metal

Match the following to its description

• Aromatic aspects of the coffee

• Fragrance

• The overall impression of coffee

• Aftertaste

• Length of + flavor left in your mouth

• Body

• The viscosity of the coffee

• Balance

• Brightness of the coffee

• Acidity

Match the following to its description

• Regulate the flow of electricity

• Thermal fuse

• Spring is compressed -> valve opens

• Check valve

• Stop the current when temp. gets high

• Spring valve

• Allow fluid to flow in 1 direction

• Electrical heater

• Resistor, allows electricity to flo thru

• Thermostat

Match the following chemical reactions during coffee roasting with their respective description:

• Maillard reactions

• Sugars and carbohydrates break down under heat in presence of O2, producing CO2 and water as byproducts

• Combustion reactions

• Chlorogenic acids breaking down under heat

• Pyrolysis reactions

• Sugars and carbohydrates break down under heat in absence of O2, giving off CO2 as a byproduct

• Acid degradation reactions

• Proteins react with sugars, giving the roasted beans its brown color, yielding aroma and flavor compounds