How To Make The Best Coffee, According To Science

Summary

This video dives into the science of brewing the perfect cup of coffee, debunking common myths and explaining the impact of various factors like the type of bean, roasting methods, brewing techniques, and water quality. From the difference between arabica and robusta beans to the importance of grind size and brewing temperature, SciShow explores how chemical reactions and physical properties shape the flavor of coffee. Ultimately, it emphasizes that while science can help improve your brew, the best cup of coffee is the one you enjoy the most.

Takeaways

• 😀 Coffee beans are actually seeds, not beans, as they come from a non-legume plant.
• 😀 The two main types of coffee beans, arabica and robusta, differ in flavor and caffeine content.
• 😀 Robusta beans are more bitter due to higher caffeine levels and more chlorogenic acid compared to arabica.
• 😀 Arabica beans have more sucrose, contributing to sweeter, caramel-like flavors during roasting.
• 😀 Lighter roasts do not necessarily have more caffeine; the difference lies in the mass and volume of the beans after roasting.
• 😀 Brewing methods like infusion, decoction, and pressure methods impact the flavor and strength of the coffee.
• 😀 The water temperature used in brewing affects the extraction of bitter and sour compounds from the coffee grounds.
• 😀 Cold brew coffee is generally sweeter and less acidic due to the longer, cooler extraction process.
• 😀 Using hard water, particularly magnesium-rich water, can enhance the flavor extraction from coffee beans.
• 😀 The grind size affects how water flows through the grounds and the extraction of flavors—fine grounds may lead to bitterness, and coarse grounds may lead to sourness.
• 😀 Ultimately, the perfect cup of coffee is subjective, and personal preference plays a large role in brewing the ideal cup.

Q & A

What is the difference between arabica and robusta coffee beans?

Arabica and robusta beans have different chemical compositions that impact flavor. Arabica beans are sweeter, with more sucrose and less bitterness, while robusta beans are more bitter, containing more caffeine and chlorogenic acid, which contribute to their astringent taste.

Why are coffee beans not technically beans?

Coffee 'beans' are actually seeds from the fruit of the coffee plant, not beans from a legume. Despite their appearance, the term 'coffee beans' is used because it is the common name in English.

Does lighter roast coffee have more caffeine than darker roast?

No, lighter roasts do not have more caffeine. The myth comes from how beans are measured; darker roasts are less dense, so if measured by volume (scoops), they may have less caffeine than lighter roasts. Caffeine content remains largely unchanged by roasting time.

How does the brewing method affect the taste of coffee?

Brewing methods influence the extraction of coffee compounds. Infusion methods like pour-over yield a milder, fruitier flavor, while decoction methods like percolators create a stronger, more bitter brew. Pressure methods like espresso extract more oils and create a deeper, creamier flavor.

What role does water quality play in brewing coffee?

Hard water, which contains magnesium and calcium ions, can enhance the extraction of coffee flavors by binding to the negatively charged parts of coffee molecules. Magnesium, in particular, binds most strongly, improving the flavor, although bicarbonates are needed to balance acidity.

How does the size of coffee grounds affect the brewing process?

Ground size impacts how water flows through the coffee. Too fine a grind leads to over-extraction, making coffee bitter, while too coarse a grind causes under-extraction, resulting in sour coffee. The correct grind size ensures optimal flavor extraction.

What is the Maillard reaction, and why is it important in coffee roasting?

The Maillard reaction is a chemical process where amino acids and sugars combine during roasting, giving coffee its characteristic brown color and complex flavors. This reaction plays a significant role in developing coffee’s sweetness and aromatic profile.

How does temperature affect coffee flavor?

Higher temperatures extract more bitter compounds from coffee, making the brew taste more bitter and earthy. Too hot, and the coffee becomes scorched or overly sour. The optimal brewing temperature is between 90 and 96°C (195-205°F), which allows for balanced extraction of flavors.

Why is cold brew coffee less acidic?

Cold brew coffee extracts flavors more slowly than hot brewed coffee due to the lower temperature, leading to a smoother and less acidic taste. Some compounds, like chlorogenic acids and trigonelline, are extracted more slowly at cooler temperatures.

What is the Darcy-Forchheimer Law, and how does it relate to brewing coffee?

The Darcy-Forchheimer Law, originally used to explain water flow through sand, helps predict how water moves through coffee grounds during brewing. It shows that the grind size affects water flow and extraction: too fine a grind creates uneven extraction, while too coarse results in under-extraction.