Coffee
Coffee Guide for Baristas and Coffee Shop Owners
A practical guide for baristas and coffee shop owners: from bean species, processing and roasting to brewing every cup consistently.
1. From cherry to cup
Coffee comes from the seed of the coffee cherry. Cherries are picked when ripe and red, then processed to separate the seed from the skin and fruit. The result is green coffee, which is then roasted, ground and brewed. Every step shapes the taste in the cup: variety, farm altitude, processing, roast and brewing.
2. Coffee species: Arabica, Robusta, Liberica
| Species | Farm altitude | Caffeine (bean) | Flavour | Best for |
|---|---|---|---|---|
| Arabica (Coffea arabica) | Usually 1,000–2,000 m | About 1.2–1.5% | Complex aroma, bright fruity acidity, sweet, light to medium body | Manual brew, single-origin espresso |
| Robusta (Coffea canephora) | Usually 200–900 m | About 2.2–2.7% | Bitter chocolate, nutty, heavy body, low acidity | Kopi tubruk, espresso blends for milk drinks |
| Liberica (Coffea liberica, incl. Excelsa) | Lowlands, tolerates peat soils | Lower than Robusta | Jackfruit, smoky, woody, distinctive | Signature and unusual single-origin menus |
Many Indonesian coffee shops use an Arabica–Robusta blend for iced coffee milk, for example 70:30. Arabica brings aroma, while Robusta brings body and a coffee taste that still comes through milk and palm sugar.
3. Processing methods
| Process | In short | Effect on flavour |
|---|---|---|
| Natural (dry) | Whole cherries are dried, then hulled | Sweet, fruity, heavy body, sometimes winey |
| Washed (fully washed) | Skin and mucilage removed, seeds fermented and washed, then dried | Clean, clear, brighter acidity |
| Honey | Skin removed, some mucilage left on during drying | Honey-like sweetness, between natural and washed |
| Wet-hulled (giling basah) | Parchment removed while the bean is still wet; typical of Sumatra and Sulawesi | Earthy, spicy, herbal, heavy body, low acidity |
| Anaerobic / experimental | Fermented in sealed tanks without oxygen | Intense fruit and wine notes, unusual |
4. Roast levels
| Level | Look | Taste | Use in a coffee shop |
|---|---|---|---|
| Light | Light brown, dry surface | Fruity acidity, floral, tea-like | V60, Japanese iced |
| Medium | Medium brown | Balanced, caramel sweetness | Espresso and manual brew |
| Medium-dark | Dark brown, slightly oily | Chocolate, nuts, heavy body | Espresso for milk drinks |
| Dark | Almost black, oily | Bitter, smoky, little acidity | Kopi tubruk, sanger |
5. Grind size
The longer the coffee is in contact with water, the coarser the grind.
| Method | Grind | Looks like | Contact time |
|---|---|---|---|
| Espresso | Fine | Coarse flour | 25–30 seconds |
| Kopi tubruk, sanger | Fine to medium-fine | Fine sand | 4 minutes |
| AeroPress | Medium-fine | Fine salt | 2 minutes |
| V60, pour over | Medium-fine | Table sugar | 2.5–3 minutes |
| French press | Coarse | Coarse salt | 4 minutes |
| Cold brew | Coarse | Breadcrumbs | 14–18 hours |
6. Coffee to water ratio
A ratio is the weight of coffee to the weight of water. Always weigh instead of using spoons, because the weight per spoon varies.
| Method | Ratio | Example | Water temperature |
|---|---|---|---|
| Espresso | 1:2 | 18 g coffee → 36 g espresso | 92–94°C |
| Ristretto | 1:1.5 | 18 g coffee → 27–28 g | 92–94°C |
| V60 / pour over | 1:15 – 1:17 | 15 g coffee : 240 g water | 92–94°C |
| Japanese iced | 1:15 (including ice) | 20 g coffee : 180 g water + 120 g ice | 93–95°C |
| French press | 1:15 – 1:16 | 15 g coffee : 240 g water | 93–95°C |
| Kopi tubruk | 1:12 | 13 g coffee : 160 ml water | 92–95°C |
| Cold brew concentrate | 1:8 | 125 g coffee : 1 litre water | Room temperature |
Use the brew calculator on the Coffee page to work out coffee and water for any number of cups.
7. Extraction: under and over
Extraction is how flavour dissolves from the grounds into the water. The goal is a sweet, balanced cup with a pleasant aftertaste.
| Under-extracted | Over-extracted | |
|---|---|---|
| Taste | Sharp sourness, salty, thin, short finish | Bitter, astringent, drying |
| Common causes | Grind too coarse, time too short, water not hot enough | Grind too fine, time too long, water too hot |
| Fix | Grind finer or extend the time | Grind coarser or shorten the time |
Change only one variable at a time, usually the grind, so you know what fixed the taste.
8. Espresso basics
- Dose: 18 g for a double basket. Weigh every time.
- Yield: 36 g in the cup, measured on a scale rather than by volume.
- Time: 25–30 seconds from pressing the button.
- Pressure: about 9 bar on a standard machine.
- Crema: the golden-brown layer on top. Pale crema that disappears quickly usually means under-extraction or stale beans.
9. Milk and microfoam
- Use cold (2–4°C) full-cream fresh milk and a cold pitcher.
- Add air at the start (stretching) for 2–5 seconds, then spin the milk (rolling) until silky.
- Finish at 60–65°C. Above 70°C the milk loses its sweetness and the foam collapses.
- Thin foam (0.5–1 cm) for lattes and flat whites, thick foam (1.5 cm) for cappuccinos.
- Wipe and purge the steam wand after every use.
10. Water for coffee
More than 98% of a cup of coffee is water. Use clear water with no smell or chlorine taste. Water with moderate minerals (about 75–150 ppm TDS) gives the best flavour. Pure distilled water (0 ppm) makes coffee flat, while very hard water dulls the taste and scales up the espresso machine.
11. Storing coffee beans
- Keep beans in an airtight bag or jar with a one-way valve, away from heat, light and moisture.
- Do not keep frequently opened beans in the fridge; condensation spoils the flavour.
- For espresso, beans taste best 7–30 days after roasting. For manual brew, 4–30 days.
- Grind just before brewing. Ground coffee loses aroma within minutes.
12. Bar standards for coffee shops
- Dial in the espresso every morning and every time you change beans.
- Weigh coffee, espresso, milk and syrup. Post the standard recipes at the bar.
- Calibrate syrup pumps: one pump is usually about 10 ml.
- Date-label syrups, cold brew and opened milk.
- Backflush the machine daily after closing and clean the grinder regularly.
- Work out the cost of every drink with the cost calculator before setting the selling price.