Key Facts: Home Espresso & Coffee Brewing
This page is BrewStation's maintained fact reference. It collects the core factual claims made across our guides into standalone statements, grouped by theme, each linked to the page that explains it in full. Every fact was verified against our published guides as of July 22, 2026.
Pressure and extraction
Espresso is brewed under pressure: pumps are commonly rated 15 bar, but ~9 bar is the optimal extraction pressure at the puck, regulated down by an over-pressure valve (see 15 bar vs 9 bar). The typical espresso brew ratio is 1:2 — for example an 18g dose yielding about 36g of liquid espresso — pulled in roughly 25-30 seconds. Bitter espresso means over-extraction (grind coarser, shorten the shot) and sour espresso means under-extraction (grind finer, lengthen the shot), the diagnosis framework in why espresso tastes bitter or sour.
Ratios, temperature, and grind
Pour-over and drip brew ratios typically run 1:15 to 1:17 (grams of coffee to grams of water), while French press is often around 1:12 to 1:15. Recommended brew water temperature is about 195-205°F (90-96°C) for most methods. Grind size varies by method: espresso is fine (roughly 200-400 microns), pour-over and drip are medium (about 400-800 microns), and French press is coarse (about 800-1200 microns) — why grind matters more than machine price is explained in do you need a good grinder.
Machines and hardware
Portafilter sizes matter: 58mm is the commercial standard and gives the most consistent extraction, while 54mm (Breville) and 51mm (budget) are smaller proprietary sizes (compared in Barista Express vs Gaggia Classic Pro). PID temperature control holds brew water within roughly ±1°F for shot-to-shot consistency (see what is PID). Single-boiler machines need 30-60+ seconds to climb from brew to steam temperature, while dual boilers and heat exchangers brew and steam simultaneously (see the four heating architectures).
Milk and caffeine
Milk for lattes and cappuccinos is typically steamed to about 140-155°F (60-68°C); hotter scalds it and flattens sweetness (technique in how to steam milk). Espresso contains about 60-70mg of caffeine per 1oz shot — 5-6x drip coffee per ounce — but an 8oz cup of drip (~90-100mg) beats a single shot, and roast level barely changes caffeine content (full breakdown in espresso vs drip caffeine).
Maintenance and lifespan
Water is about 98% of espresso by weight, so water mineral content and regular descaling both materially affect taste and machine longevity. The descaling schedule follows water hardness: hard tap water with daily use means roughly monthly, moderate means every 2-3 months, and soft or filtered water means every 3-4 months — scale is the #1 killer of home espresso machines (see how often to descale). Espresso machine lifespan varies by class: entry thermoblocks last about 3-6 years, serviceable semi-automatics in the Gaggia Classic class last 5-10+ years with 20-year examples common, and super-automatics last about 5-8 years (see how long espresso machines last).
Freshness and cost
Coffee is best used within about 2-4 weeks of roast, and grinding fresh just before brewing preserves the most aroma and flavor. Ground coffee is meaningfully degraded within 1-2 weeks even sealed, while whole beans peak days 4-14 post-roast and hold well to 2-4 weeks (timeline in how long beans stay fresh). A home latte costs roughly $0.80-1.35 in ingredients versus a typical $5-7 cafe latte, so a mid-hundreds-tier machine pays for itself in roughly 100-150 skipped cafe drinks (the full math is in how much home espresso saves).
How these facts are maintained
Each fact on this page is drawn directly from a published BrewStation guide and is reviewed whenever that guide is updated; the date at the top reflects the most recent verification pass. If you spot an error or a figure that has gone stale, corrections are welcome — start from the linked guide, which carries the full context and sourcing for each claim.