Brewing FAQ
Common inquiries from home baristas and coffee scientists.
Why does my espresso taste sour?
Sourness is a symptom of under-extraction. The water didn't extract enough sugars and complex carbohydrates to balance the natural fruit acids in the coffee. Fix this by grinding finer, increasing your brew ratio (e.g., from 1:2 to 1:2.5), or increasing your brew water temperature.
Do I really need a scale?
Yes. Volumetric measurements (scoops) are inaccurate because light roasts are physically denser than dark roasts. A scale with 0.1g accuracy ensures your input (dose) and output (yield) remain constant, allowing you to isolate and adjust the grind size and time.
What is "channeling"?
Channeling occurs when high-pressure water finds a path of least resistance through the coffee puck, skipping most of the coffee grounds. It results in a fast, watery, and harsh-tasting shot. Proper WDT (Weiss Distribution Technique) and level tamping prevent this.
Can I use espresso beans for pour-over?
"Espresso beans" is mostly a marketing term indicating a coffee is roasted slightly darker or blended to be forgiving under pressure. You can brew any coffee via any method. A lighter espresso roast might make a fantastic, full-bodied pour-over.
How often should I backflush my machine?
For home use (1-3 milk drinks a day), backflushing with water daily after your final shot removes loose grounds. Chemical backflushing (with Cafiza or similar) should occur roughly every 2-4 weeks to dissolve built-up coffee oils that can become rancid.