Brewing Espresso: What You Can Control

Coffee type

• Arabica: Lighter, fruity, sweeter, notes of chocolate.

• Robusta: Stronger, more caffeine, robust, full-bodied. Less sweet.

Roast Level

• Light

  • Tends to be more acidic, no bitterness, fruity and less forgiving of technique

• Medium

  • Tends to be more balanced with bitter and acid

• Dark

  • Tends to be more bitter, low acid, and more forgiving of technique

Age of Beans and Resting

• Fresher beans produce more crema

  • More CO2 is still trapped from roasting process

• Resting beans allows CO2 levels to decrease, which can disrupt extraction process

• Rest beans before use (espresso)

  • Dark roast: 3-10 days from roast date

  • Medium: 10-21 days from roast date

  • Light: 3+ weeks from roast date

Grind

• Grind needed will change with age of beans, temperature, humidity, etc

  • Will not always be the same for your preferred formula

• Use 2-4 spritzes of water on beans prior to grinding to help decrease static electricity

• Use a burr grinder for finer and more uniform grounds

  • Conical or Flat burr

  • Slow feed into the grinder with it already started

    • When you have too many beans trying to get through this causes a jam, and the beans rub against one another increasing static electricity and heat.

    • If you start the grinder from full stop with beans already on the burrs, you grind the first few beans at a low RPM and this increases fines and impacts the grind consistency

Water

• Soft to medium filtered water with balanced minerals

• The type of water used can greatly impact the flavor of the resulting espresso

  • Hard water tends to neutralize acidity in specialty coffees due to bicarbonate, and this can make the coffee taste flat

Temperature

• Use different temperatures depending on roast level

  • Dark: 82-86 degrees Celsius

  • Medium: 86-93 degrees Celsius

  • Light: 93-97 degrees Celsius

• Pre-heat portafilter and espresso cup

  • Run a single shot into the empty portafilter, then pull out and pour the water into the espresso cup

  • This heats up the portafilter, cup, and helps water to keep temperature consistent throughout the process

  • Also reduces heat loss due to portafilter and cup being heated up and not siphoning heat off

Brew Ratio

• This is ratio of grounds weight to shot output weight in grams

  • 18grams of coffee with 36 grams water (1:2)

  • For dark start at 1:1-1:1.5, for medium 1:2 – 1:2.5, for light 1:2.5 – 1:3.5

    • Explore from here based on your taste preferences

    • Aim to pull the shot in 25-30 seconds at first

Pull Time

• Adjust brew time by adjusting dose and grind level

• Always use pre-infusion or blooming by soaking puck for 5-30 seconds

  • This helps evenly distribute water through puck and decreases channeling

Extra Tips

• If you can use a bigger basket you can use a larger dose, and this allows you to grind coarser.

  • This decreases chances of channeling, gives a better extraction, and decreases coffee particles that get in drink which will increase the bitterness

• Coffee has 3 phases when brewing: (1)Sour/Salty, (2)Sweet, (3)Bitter

  • Use this to identify if you need to increase/decrease extraction, change your ratio, or change your grind

• Try a blooming shot

  • Pre-infuse at a low pressure and then stop pump for about 30 seconds

  • This soaks the entire puck and can improve complexity of the shot and improve extraction Enjoyed this article? Explore much more specialty coffee articles, educational resources, and my latest projects at KeithLyons.org. If you're passionate about specialty coffee, don't miss my book, The Complete World of Coffee; a comprehensive guide to the history, science, craft, and culture of coffee. Learn more at Keithlyons.org.