Coffee Lab Simulator: See How Grind, Ratio & Roast Affect Your Cup
Dial in bean, roast, grind, temperature, and ratio then hit Brew to see your predicted taste profile.
What this tool does
Every variable in coffee brewing — grind size, water temperature, brew ratio, roast level, and bean origin — affects extraction, and extraction determines flavor. The problem is that most people change one thing and taste a completely different cup, making it hard to know which variable was responsible. The Coffee Lab Simulator models these relationships interactively: adjust any variable and the taste profile bars update immediately after you brew, so you can build an intuition for how the pieces fit together before you waste a bag of expensive beans experimenting.
Bean Origin
Brew Method
Taste Profile
Adjust your variables and brew
🇪🇹 Ethiopia · Light Roast · Pour Over
How to use this tool
Choose your bean origin and brew method
Different origins start with different baseline acidity, sweetness, and aroma. Ethiopia starts very acidic and aromatic; Brazil starts low-acid and full-bodied. The brew method modifies body, bitterness, and acidity independently.
Set your roast level
Light roasts preserve origin character — floral, fruity, bright. Dark roasts develop roast flavors — chocolate, caramel, smoke — and reduce acidity. Watch how bitterness climbs and acidity drops as you drag the slider right.
Dial in grind, temperature, and ratio
Grind is the extraction rate dial: fine grinds extract fast (more bitterness risk), coarse grinds extract slow (sourness risk). Temperature amplifies extraction — especially significant for light roasts. Ratio controls strength and body.
Hit Brew and read the result
The extraction percentage tells you if your recipe is under, over, or in the ideal zone. The verdict at the bottom tells you specifically what to adjust if the profile is off.
Pro tips
- The sweet spot for extraction is roughly 55–75% on the simulator scale. Under that and you get sourness and thin body; over it and bitterness dominates.
- Cold Brew is the most forgiving method for over-extraction — the low temperature suppresses bitterness significantly. Try a dark roast on coarse grind in Cold Brew mode.
- Kenya at light roast with high temperature on Pour Over will show the most extreme acidity spike — accurate to how bright real Kenyan beans can be.
- Espresso amplifies everything: more body, more bitterness, and more intensity. A recipe that is slightly over-extracted in pour over becomes very harsh in espresso.
- Medium roast is the most forgiving roast level — it sits in the sweetness peak and balances acidity and bitterness for most origins and methods.
Why it matters
Most coffee guides give you a recipe. This simulator gives you the underlying logic — so when your cup is sour, you understand why finer grind or higher temp will fix it; when it is bitter, you know to go coarser or pull back the temperature. This is how baristas and roasters think, and once it clicks, dialing in any brew on any equipment becomes intuitive rather than accidental.
Frequently asked questions
How does grind size affect coffee flavor?
Finer grinds extract faster, pulling more compounds from the coffee in the same time. Too fine leads to over-extraction: bitter, harsh, astringent. Too coarse leads to under-extraction: sour, thin, and lacking sweetness.
How does water temperature affect extraction?
Higher temperatures extract more compounds faster. Light roasts need 93–96°C to develop fully. Dark roasts can be brewed cooler (88–92°C) to avoid excessive bitterness.
What is the difference between light and dark roast flavor?
Light roasts retain more origin character: floral, fruity, acidic, and complex. Dark roasts develop roast-driven flavors: chocolate, caramel, smoke, and low acidity. Medium roasts balance both.