How beer is made

Dry germinated grain with heat to halt modification, stabilise it for storage and develop the colour and flavour that distinguish one malt from another.

Persuade barley to begin germinating and then stop it, so the grain develops starch-converting enzymes and its starch becomes accessible.

Take malt or raw grain to high temperature in a rotating drum to produce the deep colours and roast flavours of porter, stout and dark lager.

Crack the malt kernel so water can reach its starch, while leaving the husks intact enough to form a filter bed during lautering.

Raise a mash to its next temperature step by removing part of it, boiling that portion and returning it — the traditional continental method.

Reach and hold a single conversion temperature by mixing grain with water at a calculated strike temperature, without further heating.

Sour wort with Lactobacillus before the boil, then boil to kill the bacteria and ferment clean — producing lactic acidity in days rather than years.

Bring the mash into the narrow pH band where brewing enzymes work properly, using acid, salts or acidulated malt.

Raise the finished mash to around 76 °C to stop enzyme activity, fixing the fermentability, and to thin the wort so it runs off freely.

Hold milled malt in hot water so the grain’s own enzymes convert its starch into sugars that yeast can ferment.

Acidify wort by holding the mash warm and letting lactic bacteria already present on the grain work before the boil.

Raise the mash through a sequence of held temperatures, each chosen to favour a particular enzyme, for precise control over fermentability and protein.

Run a deliberately inefficient traditional lambic mash that leaves starch and dextrin unconverted, providing long-term food for Brettanomyces.

Adjust the mineral content and alkalinity of brewing water so the mash reaches a workable pH and the finished beer has the intended balance.

Drain the mash fully, add a measured volume of rinse water, stir and drain again — trading a few points of efficiency for simplicity and speed.

Rinse the grain bed continuously, adding sparge water at the same rate wort is drawn off so a shallow layer is maintained above the grain throughout.

Separate sweet wort from spent grain, using the settled grain bed itself as the filter medium.

Mash with the full brew-length of water and skip rinsing entirely, accepting lower efficiency in exchange for a short brew day and effectively no astringency risk.

Draw several beers of descending strength from one mash by keeping the early and later runnings separate rather than combining them.

Rinse the grain bed with hot water to recover the substantial quantity of sugar that would otherwise be left behind in the liquid clinging to it.

Use hop products from which most of the leaf material has been removed, concentrating the resin and oil that carry flavour.

Add hops to the kettle as wort runs off from the mash, before the boil begins, for a bitterness widely described as smoother and better-integrated.

Add hops in the last minutes of the boil so their volatile aromatics partly survive, contributing flavour and aroma with limited additional bitterness.

Boil the wort to isomerise hop acids, sterilise it, coagulate protein, drive off unwanted volatiles and concentrate the extract to the target gravity.

Brew with hops that have never been dried, within hours of picking, for a character that does not survive drying.

Steep hops in wort held below boiling — typically 75–85 °C — to extract aroma compounds with far less isomerisation than a boil addition.

Spin the wort after the boil so trub collects in a cone at the centre of the vessel, allowing clear wort to be drawn from the side.

Cool wort overnight in a wide shallow open vessel so that airborne microflora settle into it and become the fermenting culture.

Cool boiled wort rapidly to pitching temperature, producing a good cold break and passing quickly through the range in which spoilage organisms thrive.

Dissolve oxygen into cooled wort before pitching, because yeast needs it to build the cell membranes required for healthy growth.

Add hops during active fermentation so yeast enzymes convert bound hop compounds into aromas the hop could not release on its own.

Ferment cool with Saccharomyces pastorianus, suppressing yeast-derived fruit and spice so malt and hop character stand exposed.

Raise a fermentation’s temperature near its end so the yeast reabsorbs and reduces the diacetyl it produced earlier.

Ferment a stronger wort than the finished beer requires, then dilute to sale strength with deaerated water after fermentation.

Explain the renewed fermentation that dry hopping can start in beer that had already finished, and the over-carbonation and dryness that follow it.

Ferment with a deliberately chosen combination of organisms — Saccharomyces with Brettanomyces, Lactobacillus and/or Pediococcus — over months or years.

Ferment in a vessel open to the air, allowing krausen to be skimmed and yeast to be cropped from the surface.

Add yeast to cooled, oxygenated wort at a rate matched to the volume, gravity and fermentation temperature.

Ferment under applied top pressure to suppress ester and fusel production, allowing warmer and therefore faster fermentation without the flavour penalty.

Convert wort sugars into ethanol, carbon dioxide and the esters, phenols and higher alcohols that give beer much of its character.

Allow ambient microorganisms to inoculate cooling wort rather than pitching a culture, producing lambic and its derivatives.

Ferment warm with Saccharomyces cerevisiae, producing the ester and phenol character that distinguishes ales from lagers.

Collect yeast from a finished fermentation and pitch it into the next batch, generation after generation.

Mature beer in wooden barrels for the wood and spirit character they contribute, or for the microflora they harbour and the slow oxygen exchange they allow.

Combine beers of different ages or batches to produce a consistent or more complex result than any single batch would give.

Complete fermentation and carbonation inside the cask the beer will be served from, so it arrives at the drinker alive.

Receive, stillage, vent, fine and temperature-manage cask beer in the pub so it reaches the drinker in condition.

Mature beer after primary fermentation so flavours settle, harsh young compounds are cleared and carbonation reaches equilibrium.

Add hops to beer after fermentation, without heat, to extract aroma compounds while adding essentially no bitterness.

Concentrate a finished beer by freezing it and removing ice, raising strength and body without further fermentation.

Store beer cold for an extended period after fermentation to clarify it and produce the clean, rounded character lagers are named for.

Separate yeast and solids from beer by density at high rotational speed, as a faster and gentler alternative to tight filtration.

Chill finished beer sharply to near freezing to force yeast and haze-forming material out of suspension before packaging.

Pass beer through a filter medium to remove yeast and haze-forming particles, producing bright beer with a long, stable shelf life.

Add a substance that binds with haze-forming material and drags it out of suspension, clarifying wort or beer without filtration.

Carbonate beer through a secondary fermentation inside the sealed bottle, using residual or freshly-added yeast with priming sugar.

Dissolve CO₂ into beer under applied pressure rather than producing it by fermentation, giving fast and precise control of the level.

Carbonate beer by adding actively fermenting wort rather than refined sugar — the traditional German method.

Dissolve nitrogen alongside a low level of CO₂ so the beer pours with a dense creamy head and drinks soft rather than sharp.

Add a measured quantity of fermentable sugar at packaging so residual yeast generates the intended carbonation in the container.

Admit carbon dioxide at atmospheric pressure to replace beer drawn from a cask, instead of letting air in.

Move finished beer into its final container with as little oxygen pickup as possible, because oxygen taken up here determines how the beer ages.

Heat beer enough to kill yeast and spoilage organisms, greatly extending microbiological stability across a long supply chain.

Stop fermentation deliberately and early — by chilling, filtering or pasteurising — so little alcohol is produced.

Ferment with a yeast that cannot consume maltose, so a normal wort produces only a fraction of a percent of alcohol.

Remove alcohol by forcing beer against a membrane that passes water and ethanol while retaining larger flavour molecules.

Strip alcohol from finished beer at low temperature by running it as a thin film over rotating cones against a gas flow.

Remove alcohol from finished beer by distilling under reduced pressure, so ethanol boils off at a temperature low enough not to cook the beer.

Hold packaged beer warm for a fixed period to accelerate staling, predicting in days how it will taste after months on a shelf.

Assess beer against its own specification using trained tasters, screened and calibrated against known spiked standards.