Optimal Coffee Brewing Explained

When coffee is brewed correctly, there is truly nothing like it. You do a double-take, look incredulously at the cup in your hand and say, “man … that’s GOOD.”

But in order for the coffee to come out just right, the correct brew parameters must be in place: water quality, water-to-coffee ratio, water temperature, and grind. When brewed correctly, the coffee’s best flavors are released quickly, and bitterness will be present, but it will be perceived as more of an aftertaste or “finish.” Cutting off the extraction at a certain point can control the amount of bitterness.

The ideal cup

The ideal cup

However, when coffee is brewed poorly, you can be left with a weak or bitter or *gulp* weak AND bitter cup of coffee.

Water Not Hot Enough

If the water is less than 190º F., the best flavors are not extracted, but the more soluble bitter flavors will be. The product will taste weak and bitter.

Water not hot enough will lead to bitter, weak coffee

Water not hot enough will lead to bitter, weak coffee

Water Too Hot

If the water is above 205ºF, all soluble material, including less desirable material, is quickly extracted, resulting in a strong bitter cup.


Water over 205F results in strong, bitter coffee

Water over 205F results in strong, bitter coffee



Coffee Grind Too Fine

When the coffee is ground too fine (particle sizes too small), the best flavor is quickly extracted. More of the bitter flavors will also emerge after the better flavors have been washed out.

Too fine of grind leads to bitter coffee

Too fine of grind leads to bitter coffee

Grind Too Coarse

When the coffee is ground too coarse (particle sizes too large), the brewing process proceeds slowly. The best flavors are not dominant and the cup will taste weak and somewhat bitter or astringent.

Too coarse of grind results in weak coffee

Too coarse of grind results in weak coffee


6 comments to Optimal Coffee Brewing Explained

  • avatar Michael

    Could you give a little info on how you came up with the graphs? I see no data, just rough estimations.

  • Hello Michael

    Thank you for your question. The data collected to create these graphs is from our trained sensory panel. We conducted sensory testing in early 2011 using the Specialty Coffee Association’s Golden Cup brew chart as reference.

    Spencer Turer
    Director of Coffee Operations – Coffee Analysts

  • avatar c.b.borkar

    If I heat the water to your recommended temperature
    and poured the water in to a filter that holds the grind
    Vs. making it in a cofee maker, does it make any difference?


  • avatar Spencer Turer

    The only variation will be the speed of the hot water drip which will affect the rate of extraction. Some brewers have a slow steady drip, others will add a lot of water filling up the brew basket and then delay as the coffee drips through the filter, others will pulse the water stream on and off throughout the brew cycle, and even other coffee makers will only dispense a specific amount of water over the coffee grinds and allow other hot water to bypass the coffee directly into the carafe.

    Each process will produce a different flavor and aroma attribute in the finished beverage, and should be experimented on for your particular preferences.

    The process described is often called a pour-over and is similar to Melitta, Chemex, Hario, and Clever brewing systems.


  • avatar Jef

    Thanks for these, i’m entering an Aeropress contest in a couple of months and these explanations really help!

  • avatar Christine Hibma

    You’re welcome and good luck!

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