Beer
The world's most consumed alcoholic drink. Over 150 documented styles. Fermentation by two species of yeast, at two temperatures, producing two entirely different drink families.
Looking for a specific beer? The Codex is organised by style, not brand — so Kingfisher, Heineken and Budweiser live under Lager, Guinness under Stout & Porter, and so on. You can also type a brand name straight into the search box and it will take you to the right style.
🌍 Browse beer brands by country: Ireland · USA
Pale Ale & IPA
From English Bitter to West Coast IPA to Hazy NEIPA — the complete family of pale, hop-forward ales. Burton water, dry-hopping, IBU, and the revolution that craft beer sparked.
Stout & Porter
Roasted barley chemistry, the Guinness draught system, Imperial Stout, Baltic Porter. Dark beers from London's porter tradition to modern barrel-aged expressions.
Lager
S. pastorianus, cold fermentation, German Reinheitsgebot 1516, Pilsner Urquell 1842, Märzen, Bock, Helles. The science of cold-conditioning and why lager dominates global beer production.
Wheat Beer
German Weizen (4-vinyl guaiacol, isoamyl acetate), Witbier (coriander, orange peel), Berliner Weisse, Gose. The role of ferulic acid rest and 4VG in Hefeweizen's distinctive character.
Belgian Ale
Trappist brewing, Dubbel, Tripel, Quadrupel, Saison, Abbey ales. Belgian yeast chemistry — why Belgian yeast produces phenolic and ester complexity that other ale yeasts do not.
Sour Beer
Lambic, Gueuze, Kriek, Flanders Red, Berliner Weisse, Gose, Kettle Sour. Brettanomyces, Lactobacillus, Pediococcus — the microbiology of controlled fermentation. Coolship inoculation.
Czech Pilsner
Invented 5 Oct 1842 by Josef Groll in Plzeň. Saaz hops, very soft water, triple decoction mash. The world's most copied beer style. Pilsner Urquell. BJCP 3B.
Märzen / Oktoberfest
Brewed in March, stored through summer, served at Oktoberfest. Gabriel Sedlmayr/Spaten 1841. Vienna malt amber lager. Munich-only rule. BJCP 6B.
Bock
Strong German lager family. Traditional (6.3–7.2%), Maibock, Doppelbock (7–10%, "-ator" suffix), Eisbock (9–14%). Einbeck origin, Paulaner Salvator 1629.
Kölsch
Pale, delicate ale/lager hybrid from Cologne only. Kölsch Konvention 1985 + EU GI 1997. Stange glass, 200 mL. Köbes service tradition.
Brown Ale
Malt-forward, caramel, toffee, low bitterness. English tradition (Mann's 1902, Newcastle 1927) vs American craft reinvention. BJCP 13B/19C.
Beer Styles Overview
The full map of beer styles and how they relate — ale vs lager, the major families, and where each style sits. The best starting point if you're not sure which style page you want.
Water Chemistry
Why water makes the beer: the mineral ions (calcium, sulfate, chloride, carbonate), the Burton vs Pilsen vs Dublin water profiles, residual alkalinity and mash pH, and how brewers build water to suit a style.
Beer is an alcoholic drink produced by the fermentation of malted cereal grain — predominantly malted barley (Hordeum vulgare) — with water, hops (Humulus lupulus), and yeast. The fundamental biochemistry: malted grain provides starch; mashing with hot water converts starch to fermentable sugars (principally maltose) via enzymatic hydrolysis; yeast (primarily Saccharomyces cerevisiae for ales or Saccharomyces pastorianus for lagers) ferments the sugars to ethanol and carbon dioxide; hops provide bitterness (from isohumulones derived from alpha acids), aroma, and antimicrobial stabilisation. Beer is classified by fermentation type: ales (top-fermenting S. cerevisiae, typically 15–24°C, faster, more ester-driven), lagers (bottom-fermenting S. pastorianus, typically 7–13°C, slower, cleaner), and spontaneously fermented beers (wild yeast and bacteria, primarily Brettanomyces/Dekkera and Lactobacillus/Pediococcus). The primary style classification system for competition and education is the BJCP (Beer Judge Certification Program) Style Guidelines, maintained by the Beer Judge Certification Program, Inc., with the current edition published in 2021. The Brewers Association (USA) maintains a parallel craft beer style guidelines document.
Ale vs lager — the fundamental divide
Every beer in the world is one of three fermentation types: ale, lager, or spontaneous fermentation. The distinction is not about colour, strength, or bitterness — it is entirely about the yeast species and fermentation temperature.
Ales use Saccharomyces cerevisiae, fermented at 15–24°C. The higher temperature produces a more complex ester and fusel alcohol profile — fruity, yeasty, aromatic. Most of the world's oldest beer styles are ales: Pale Ales, IPAs, Stouts, Porters, Wheat Beers, Belgian ales, and sour beers.
Lagers use Saccharomyces pastorianus (a natural hybrid of S. cerevisiae and S. eubayanus, first documented in Bavaria), fermented at 7–13°C and then lagered (cold-conditioned) for weeks to months. The cold fermentation suppresses ester production — producing a clean, crisp, less aromatic character. Most commercial beer sold globally is lager.
Spontaneous fermentation uses ambient wild yeast and bacteria rather than cultivated yeast — producing highly complex, acidic, often funky beers. The classic examples are Belgian Lambic and Gueuze. This category includes most sour beers.
| Scale | What it measures | Range for common styles | Notes |
|---|---|---|---|
| IBU (International Bitterness Units) | Perceived bitterness from isohumulones (hop alpha acid isomers) | 5 IBU (Berliner Weisse) → 120+ IBU (Imperial IPA) | Human perception threshold ~5–10 IBU. High residual sugar can mask bitterness, so perceived bitterness ≠ IBU number. |
| SRM (Standard Reference Method) | Beer colour — measured photometrically at 430nm | 2 SRM (pale lager) → 40+ SRM (stout) | SRM 4 = pale golden; 10 = amber; 20 = brown; 35+ = opaque black. Related to roasted malt content. |
| OG / FG (Original / Final Gravity) | Sugar content (OG = before fermentation; FG = after) | OG 1.030–1.120 for most styles | Density relative to water (1.000). Difference OG−FG ÷ 7.46 ≈ ABV. Measured in Plato (°P) in Europe. |
| ABV (Alcohol By Volume) | Ethanol percentage | 3% (session ales) → 15%+ (imperial stouts) | Approximate formula: (OG − FG) × 131.25 = ABV% |
Coming next in Beer
Amber & Red Ale · Scottish Ale · Altbier · Smoked Beer (Rauchbier) · American adjunct lager · Traditional grain beers by country. Phase 5 onward: Rum, Gin, Vodka, Brandy, Tequila, Mezcal, Sake, Baijiu, Soju.