Nancy Deng | January 6th, 2025
Why does the coffee made by a barista at a café often taste superior to coffee brewed at home?
While it may depend on their years of experience and training, science also plays a significant role. Key variables like coffee bean quality, brewing temperature, grind coarseness, and coffee-to-water ratio determine the flavor and consistency of the perfect cup. By understanding and controlling these factors, you can elevate your home-brewed coffee.
Coffee bean quality
Great coffee starts with high-quality beans. The flavor depends not only on the brewing process but also on the type of coffee you select. While coffee flavor is subjective, some factors in choosing the right coffee include bean country and origin, variety, roast type, and texture. Freshness is crucial — roasted coffee contains a significant amount of carbon dioxide and other volatile (easily evaporating) compounds that enhance flavor. Over time, these gases escape, leaving the beans less flavorful. Therefore, pre-ground coffee may be less desirable than freshly ground coffee because it loses freshness faster due to more exposure to air, resulting in a less flavorful cup of coffee.
Brewing temperature
Temperature affects the extraction of compounds from coffee grounds. For instance, ice water produces a weak pour-over, while boiling water extracts more flavors and caffeine. Temperature also plays an important role in taste and caffeine levels, with hotter temperatures extracting more caffeine and organic compounds extracting caffeine much faster. Cold-brewed coffee, steeped overnight in a fridge, is smoother and less caffeinated compared to a hot-brewed cup, which delivers a bolder flavor and stronger caffeine kick.
Grind coarseness
The grind size controls the rate of extraction. Finer grinds expose more surface area in contact with water, leading to faster extraction of tasty, aromatic compounds. Coarser grinds, with less surface area, slow the process. The ideal balance is a medium blend for a flavorful and well-extracted brew. The time it takes for hot water to pass through the coffee also determines the strength of the coffee, with finer grounds producing a more caffeinated cup.
Coffee-to-water ratio
The coffee-to-water ratio is critical to achieving a smooth and rich taste. Too little coffee makes the brew weak, while too much results in an overpowering strong flavor. For drip coffee, a lower coffee-to-water ratio works best due to the higher water temperature and increased extraction rate. Adjusting the ratio to your taste preferences can help create a smoother, more enjoyable cup.
The next time you make coffee, experiment with these variables to discover your perfect cup of coffee. With practice, you can recreate the café experience in your own home, cup after cup.
References
How to Brew Coffee. National Coffee Association USA. https://www.ncausa.org/About-Coffee/How-to-Brew-Coffee
The Science Behind That Perfect Morning Cup of Coffee. Coffee Science. https://www.coffeescience.org/science-behind-perfect-morning-cup-coffee/.
Pre-Ground Coffee, Is it That Bad? Fox Coffee. https://www.foxcoffee.com.au/blogs/blog/pre-ground-coffee-is-it-that-bad