When espresso is bitter?

by John Herriott

When espresso tastes bitter, it is often an indication of over-extraction. Over-extraction occurs when hot water has been in contact with the coffee grounds for too long, extracting excessive amounts of bitter compounds from the coffee. This can lead to a harsh and unpleasant bitterness in the final cup.

Here are common reasons why espresso may taste bitter and some potential solutions:

  1. Grind Size:

    • Issue: The coffee grounds may be too fine, leading to a slower extraction and over-extraction.
    • Solution: Adjust the grind size to make it coarser. A coarser grind allows water to flow through more quickly, reducing the risk of over-extraction.

  2. Brewing Time:

    • Issue: The brewing time may be too long, causing the water to be in contact with the coffee grounds for an extended period.
    • Solution: Decrease the brewing time by adjusting the grind size, tamping pressure, or the amount of coffee in the portafilter.

  3. Tamping Pressure:

    • Issue: Over-tamping can lead to a slower flow of water through the coffee grounds, contributing to over-extraction.
    • Solution: Tamp with consistent and moderate pressure. Avoid excessive force, which can compress the coffee too much.

  4. Coffee Dose:

    • Issue: Using too much coffee in the portafilter can contribute to over-extraction.
    • Solution: Decrease the coffee dose to ensure a balanced extraction. Experiment with different doses to find the optimal amount.

  5. Water Temperature:

    • Issue: Water that is too hot may extract undesirable bitter flavors from the coffee.
    • Solution: Check and adjust the water temperature to ensure it falls within the recommended range (around 195–205°F or 90–96°C).

  6. Quality of Coffee Beans:

    • Issue: Low-quality or overly roasted coffee beans can contribute to a bitter taste.
    • Solution: Use fresh, high-quality coffee beans with a roast profile suitable for espresso. Consider experimenting with different bean varieties.

  7. Machine Calibration:

    • Issue: Inconsistent machine calibration or issues with the espresso machine.
    • Solution: Ensure that your espresso machine is calibrated properly. If there are issues, consult a professional technician for maintenance or adjustments.

It's crucial to note that achieving the right balance in espresso extraction requires some experimentation. Small adjustments to variables such as grind size, dose, and brewing time can have a significant impact on the flavor profile. As you make adjustments, taste the espresso regularly to find the optimal combination that results in a well-balanced and enjoyable shot.

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