Science Behind A Cold Cup Of Coffee
Have you ever made a hot cup of coffee and let it cool or placed it in the fridge? You go to sip it and notice it develops a bitter, acidic taste, but if you drink cold brew, it doesn’t have that same bitter taste.
Here’s the science behind why:
This is because coffee contains chlorogenic acids, which aren’t naturally bitter but transform into lactones when roasted. Upon brewing, lactones start to break down into acids, and pH of brewed coffee can drop 15 percent in an hour, resulting in a bitter taste. So here is how to avoid that.
Impact of Temperature
Duration and temperature of extraction have a significant impact on flavor and bitterness. Higher temperatures extract more compounds, producing a more robust flavor and potentially bitter brew. This is due to the molecules and atoms moving more quickly in hot water. The more thermal energy allows more extraction from coffee grounds. Cold water moves slowly and has less thermal energy. This is why cold brew is less acidic and less bitter.
The extended steeping time allows for a slow extraction of flavor. Doing a courser grind helps prevent over-extraction, which could taste bitter.
Coffee Grounds
Start with room temperature or cold water and add coffee grounds. A courser grind helps prevent over-extraction, which could produce a bitter flavor. Stir and refrigerate for 12-24 hours. Strain through a coffee filter, mesh, or French press and store in a container in the refrigerator.
What to do if Coffee is Bitter
If you want iced coffee, it is about not allowing the lactones to break down. It’s best to brew the coffee twice as strong as you usually would (it will be watered down). Pour the hot coffee immediately over ice in a flash chill. The faster you pour, the less the lactones have to break down. You can also add a pinch of salt or baking soda to raise the pH, preventing a bitter taste.
SOURCES
Domuschiev, Ivan 2024/01/09, The interaction between coffee and quantum energy
Howard Baker, New Scientist, The surprising connection between quantum physics and coffee by Sanjeyan
Alex G. Randa, Rusdianasari Rusdianasari Adi Setiawan Faisal, Thermal decomposition of Gayo Arabica coffee-pulp in a segmented chamber
Bilhat Leta Chala, Hans Oechsner, Joachim Müller, Introducing Temperature as Variable Parameter into Kinetic Models for Anaerobic Fermentation of Coffee Husk, Pulp and Mucilage Jan 2019
Michael Spiro, Ralf Toumi, Mangayetkarasy Kandiah, The kinetics and mechanism of caffeine infusion from coffee: The hindrance factor in intra-bean diffusion
