☕ All About CoffeeScience, Taste & Health
🧪 Coffee Science
⚖️ Extraction Calculator
If you have a refractometer, enter your TDS. If not, the slider below is for understanding.
Extraction yield: 19.5%
Within the commonly targeted range. Taste is the final judge.
Typical TDS: filter about 1.15–1.35%; espresso about 8–12%. Guidelines, not rules.
☕ Under to over-extraction
Illustrative; real taste depends on the coffee and method.
💧 Water chemistry (SCA targets)
- TDS: about 150 mg/L (acceptable 75–250)
- Alkalinity: about 40 ppm; pH about 7 (6.5–7.5)
- Hardness: roughly 50–175 ppm (as CaCO₃); figures vary by edition
- Chlorine-free, odour-free water
Very low-mineral water (some RO or distilled water) tends to make coffee taste flat. Check your water with a TDS meter.
Simple first, then deeper
Caffeine · कैफ़ीन
Simple: A natural stimulant in coffee.
Deeper: It is an alkaloid that dissolves readily in hot water. Robusta usually has more than Arabica. It adds some bitterness, but much of coffee's bitterness comes from other compounds formed in roasting.
Acidity · एसिडिटी
Simple: The pleasant brightness, like in fruit.
Deeper: Coffee contains organic acids. Perceived acidity is not the same as measured pH, and some acids (such as chlorogenic acids) break down as roasting progresses.
Aroma & flavour · सुगंध और स्वाद
Simple: Mostly what you smell, not only taste.
Deeper: Hundreds of volatile compounds contribute. They reach your nose directly and through the back of the mouth when you sip, which is why a blocked nose dulls flavour.
Roasting chemistry · रोस्टिंग रसायन
Simple: Heat turns green beans brown and flavourful.
Deeper: The Maillard reaction (amino acids + sugars) builds colour and aroma. Sugar caramelization, acid breakdown and CO₂ formation also occur. Longer or hotter roasting shifts flavour from bright toward roasty.
Particle size · कणों का आकार
Simple: Finer grounds extract faster.
Deeper: Smaller particles have more surface area, so water dissolves compounds faster. A very uneven grind mixes under- and over-extracted particles; too many fines can clog the bed or add harshness.
Temperature, time & pressure · तापमान, समय और दबाव
Simple: Hotter, longer, or more pressure extracts more.
Deeper: SCA's reference water is about 93°C ±3. Filter methods usually run several minutes; espresso uses fine grounds, short time and high pressure (commonly around 9 bar). Change one variable at a time.
Fermentation · फ़र्मेंटेशन
Simple: Microbes act on the fruit sugars after harvest.
Deeper: In processing, microbes break down mucilage sugars and can change flavour precursors. Controlled fermentation is an emerging area; results are not guaranteed.
Staling & storage · बासीपन और भंडारण
Simple: Coffee loses aroma with time and air.
Deeper: After roasting, CO₂ escapes (degassing) and oxygen slowly degrades aroma compounds. Ground coffee stales faster because more surface is exposed. Store airtight, cool and dark.
Sources & References
INDUSTRYSCA: Golden Cup standard (TDS 1.15–1.35%, extraction yield 18–22%, about 55 g/L, water about 93°C ±3, contact about 4–8 min for filter) and the SCA water standard, as summarised by several educational sources.
Espresso beverage TDS is typically about 8–12%. These are guideline zones, not laws: taste is the final judge. Check the SCA for current documents. Last updated: Oct 2026.
👃 Tasting & Cupping
Sensory vocabulary
Fragrance & aroma
Acidity
Sweetness
Bitterness
Body & mouthfeel
Flavour
Aftertaste
Balance
Fragrance is the smell of dry ground coffee; aroma is the smell once water is added.
🎯 Try: Smell the dry grounds, then the wet brew, and note how they differ.
Words for what you smell and taste
Fruity: berry, citrus, apple, stone fruit
A simple original list, not the official flavour wheel.
🥣 Home cupping calculator & timer
The SCA cupping method: 8.25 g coffee per 150 ml water, water at about 93°C, steep about 4 minutes, then break the crust (stir 3 times) and smell.
Beginner tasting exercises
🌡️ Taste it as it cools
Brew a cup and taste it hot, warm and cool. Write down what changes: acidity and sweetness often seem to change as it cools.
🧂 Train your nose
Smell a few kitchen items such as cocoa, cinnamon, dried fruit and nuts. Then smell a coffee and see which one it reminds you of.
⚔️ Compare two coffees
Brew two coffees the same way and taste side by side. Note which is brighter, heavier or sweeter, and which you prefer. Preference is personal.
🏅 Modern professional approaches
The traditional SCA cupping form scores ten attributes on a 6–10 scale. The newer SCA Coffee Value Assessment (CVA) separates assessments instead of one number: physical (green quality), descriptive (what flavours are present), affective (how much you like it) and extrinsic (origin, certifications, story). This is my own explanation, not the official form.
Sources & References
INDUSTRYSCA: cupping protocol (8.25 g / 150 ml, 93°C, about 4-minute steep) and the Coffee Value Assessment, as summarised by several educational guides and the SCAA 2005 cupping protocol document.
Descriptor lists here are simplified and original; they are not the SCA Flavor Wheel. Last updated: Oct 2026.
👅 Tasting Journal
🔬 Evidence Notes: Cupping, Sensory Science, Decaf & Health
Extra notes explained in our own words from public sources, each with its link. Health points describe what research and regulators say, not advice for any one person. Where a figure comes from a hosted copy or a secondary page, we say so.
Cupping: the standard idea
- Cupping is a structured way to taste coffee side by side. In the SCA cupping protocol, as a hosted copy shows it, about 8.25 g of coffee goes into 150 mL of water (roughly 1:18) at about 92 to 94 °C, five cups are prepared per sample, and the crust is broken after about four minutes.
- The same copy says 70 to 75 percent of the grounds should pass a #20 sieve. Always check the current SCA document, as protocols are revised.
Describing flavour: the sensory lexicon
- World Coffee Research's Sensory Lexicon identifies 110 flavour, aroma and texture attributes with reference samples, so tasters can describe and measure coffee in the same way.
- Tasting words are shared vocabulary, not facts about the bean. Two people can honestly describe the same cup differently.
Decaffeination in brief
- Common approaches use a solvent (for example dichloromethane or ethyl acetate), supercritical carbon dioxide, or a water-based process in which caffeine is removed from the soak water and the water is reused.
- In the EU, a directive on coffee extracts lets soluble coffee extract be called "decaffeinated" if anhydrous caffeine is no more than 0.3 percent of the dry matter. We did not verify limits for roasted coffee, so check the rules for your market.
- Decaf is not caffeine-free; it has much less caffeine.
Caffeine intake guidance (EFSA)
- The European Food Safety Authority says single doses up to 200 mg and total intake up to 400 mg a day are not a safety concern for healthy adults. It also notes that 100 mg close to bedtime may disturb sleep in some adults.
- For pregnant and breastfeeding women the figure is up to 200 mg a day from all sources, and for children and adolescents about 3 mg per kg of body weight per day.
- These are population guidance values. Individuals react differently; see our caffeine estimator and speak to a doctor if you have a heart, sleep or pregnancy concern.
IARC and very hot drinks
- In 2016 IARC (the WHO's cancer agency) concluded there was inadequate evidence that drinking coffee causes cancer, placing it in Group 3, "not classifiable". Group 3 describes the strength of evidence, not the size of any risk.
- The same review found that drinking very hot beverages, above about 65 °C, probably causes oesophageal cancer (Group 2A). Let a very hot cup cool a little.
Blood pressure, heart and sleep: what reviews say
- An open-access review reports that coffee may raise blood pressure for a short time with no effect on long-term levels, and that cohort studies do not show a higher risk of hypertension. People with uncontrolled high blood pressure are advised to avoid large caffeine doses.
- The same kind of evidence links moderate coffee to possibly lower stroke risk, mixed or no association for coronary disease, and a J-shaped pattern for heart failure. Most of this is observational, so it shows association, not proof of cause.
- A meta-analysis of 24 controlled crossover studies found that caffeine (not coffee only) delayed falling asleep by about 9 minutes, cut total sleep by about 45 minutes and lowered sleep efficiency. Timing and personal sensitivity matter.
Official links
⚠️ This is general information from public sources, not medical advice. Ask a doctor about caffeine if you are pregnant, have heart, blood pressure or sleep problems, or take medicines.
❤️ Coffee & Health
This section is for educational purposes and is not a substitute for medical advice.
STRONG EVIDENCE
- Caffeine is a stimulant that can increase alertness (EFSA evidence supports this at roughly 75 mg or more per serving).
- Caffeine can disturb sleep: single doses of about 100 mg may delay falling asleep and shorten sleep in some adults, especially near bedtime.
- Reference points for healthy adults: up to about 400 mg a day and single doses up to about 200 mg (EFSA, 2015). The US FDA also cites 400 mg a day.
- Pregnancy and breastfeeding: EFSA suggests up to about 200 mg a day. Children and teens: about 3 mg per kg of body weight a day.
LIMITED / EMERGING EVIDENCE
- Many large observational studies link moderate coffee drinking to lower or neutral risk for several long-term conditions, but such studies cannot prove cause and effect.
- Effects on blood pressure, heart rhythm and anxiety differ from person to person.
UNCERTAIN
- Whether coffee itself, other compounds, or lifestyle differences explain observed links; how genetics changes caffeine sensitivity; effects of very high intakes.
UNSUPPORTED CLAIMS
- “Coffee cures or treats a disease.”
- “Coffee detoxes or cleanses the body.”
- “Coffee alone causes reliable weight loss.”
☕ Caffeine Estimator
0 mg
Reference (EFSA): 400 mg/day
Estimate is within the reference level.
A rough estimate, not medical advice. Sensitivity differs between people.
If you are pregnant or breastfeeding, caring for a child, have a heart or sleep condition, or take medicines, ask your doctor or pharmacist about caffeine.
Sources & References
SCIENTIFICEFSA: Scientific Opinion on the safety of caffeine (2015).
GOVERNMENTUS FDA: consumer guidance on caffeine.
Caffeine per serving varies widely by bean, roast, brew method and size; figures here are rough typical values. Limited-evidence statements are general summaries of observational research. Last updated: Oct 2026.