Homebrewing Glossary: Brewing Terms and Definitions

Homebrewing Glossary: Brewing Terms and Definitions

This homebrewing glossary explains common brewing terms used in beer recipes, brewing equipment instructions and product descriptions. Use it to understand all-grain brewing, extract brewing, fermentation, yeast, hops, grain, water chemistry, beer colour, carbonation and electric brewing systems.

Brewing terminology can vary between equipment manufacturers, malt producers and recipe writers. These brewing definitions provide a practical starting point for homebrewers.

A–C | D–H | I–M | N–R | S–Z

Brewing Terms: A–C

ABV (Alcohol by Volume)
The percentage of a beverage’s total volume that consists of alcohol. Homebrewers commonly estimate ABV using original gravity and final gravity readings.
Acetaldehyde
A fermentation compound often described as tasting or smelling like green apple or freshly cut pumpkin. It may be present in young beer or beer removed from the yeast too early.
Acid Rest
A low-temperature mash rest historically used to lower mash pH. Modern brewing water adjustments have made a separate acid rest less common.
Adjunct
A fermentable or non-fermentable ingredient used in addition to a recipe’s primary malt. Brewing adjuncts include corn, rice, oats, sugar, fruit, herbs, spices and flavouring ingredients.
Aeration
The addition of oxygen to cooled wort before pitching yeast. Yeast uses oxygen during its early growth phase, but oxygen introduced after fermentation begins can cause oxidation.
Airlock
A device fitted to a fermenter that allows fermentation gas to escape while limiting the entry of air and contaminants.
Alcohol Tolerance
The approximate alcohol level at which a yeast strain becomes stressed or stops fermenting effectively.
Ale
Beer fermented with an ale yeast strain, generally at warmer temperatures than lager fermentation. Ale yeast includes many strains of Saccharomyces cerevisiae.
Ale Yeast
A group of yeast strains commonly used to ferment ales. Ale yeast can produce a wide range of clean, fruity, spicy or expressive fermentation characteristics.
Alkalinity
The ability of brewing water to resist a reduction in pH. High alkalinity may require acid treatment when brewing pale beer.
All-Grain Brewing
A brewing method in which crushed malted grain supplies the fermentable sugars. The grain is mashed with water to convert starch into sugar before the wort is boiled.
All-in-One Brewing System
An electric brewing system that combines a kettle, heating elements, temperature controller and removable mash pipe or grain basket in one vessel.
Alpha Acid
Bittering compounds found in hops. The alpha-acid percentage helps brewers estimate how much bitterness a hop addition may contribute.
Apparent Attenuation
The percentage of wort sugars that appear to have been fermented, calculated from original gravity and final gravity readings.
Astringency
A dry, puckering mouthfeel that may result from excessive tannin extraction, high sparge-water pH, oversparging or certain ingredients.
Attenuation
The extent to which yeast converts fermentable sugars into alcohol and carbon dioxide. Higher attenuation generally produces a drier finished beer.
Base Malt
Malt that makes up most of a grain bill and supplies fermentable sugar and enzymes. Common base malts include Pilsner, pale ale, two-row, Vienna and Munich malt.
Batch Size
The intended volume of wort or finished beer produced by a brewing recipe. Pre-boil, post-boil and packaged batch volumes may be different.
Beta Acid
Hop compounds that contribute less immediate bitterness than alpha acids but can affect flavour and bitterness as hops and beer age.
Beta-Glucan Rest
A mash rest used to break down beta-glucans found in grains such as rye, wheat and oats. It may improve wort flow when using large amounts of these grains.
BIAB (Brew in a Bag)
An all-grain brewing method that uses a mesh bag or basket to hold the grain during the mash. The grain is lifted from the kettle before the wort is boiled.
Biofine
A silica-based fining agent used to help yeast and haze-forming particles settle from beer.
Bittering Addition
A hop addition made early in the boil to extract bitterness. Longer boiling generally increases hop utilization while reducing volatile hop aroma.
Blow-Off Tube
A larger outlet tube used instead of a standard airlock during vigorous fermentation. It directs foam, yeast and gas into a separate container.
Body
The perceived weight, fullness or thickness of a beer in the mouth. Body is affected by residual sugar, protein, alcohol, carbonation and ingredients.
Boil-Off Rate
The volume of liquid lost through evaporation during the boil, usually expressed as litres or gallons per hour.
Bottle Conditioning
Carbonating beer inside a sealed bottle by adding a measured amount of fermentable sugar and allowing yeast to produce carbon dioxide.
Brettanomyces
A genus of yeast used intentionally in some sour and mixed-fermentation beers. Depending on the strain and conditions, it may produce fruity, earthy, leathery or funky flavours.
Brewhouse Efficiency
The percentage of potential grain extract that reaches the fermenter. It includes losses during mashing, lautering, boiling and transfer.
Brewing Liquor
Water prepared for brewing. The term distinguishes brewing water from the finished beverage.
Brewing Salt
A mineral addition used to adjust brewing-water chemistry. Common brewing salts include calcium chloride, calcium sulphate and magnesium sulphate.
Brix
A scale representing the approximate percentage of dissolved sugar by weight in a liquid. Refractometers commonly display wort concentration in degrees Brix.
Calcium Chloride
A brewing-water mineral that adds calcium and chloride. Chloride can help emphasize malt character and fullness.
Carbonation
Dissolved carbon dioxide in beer or another beverage. Carbonation can be produced naturally through fermentation or added using pressurized CO2.
Carbonation Stone
A porous stainless steel stone that breaks CO2 into very small bubbles to speed gas absorption into a beverage.
Caramel Malt
Specialty malt produced to develop caramelized sugars and flavours. Caramel malt can add colour, sweetness, body and flavours ranging from light caramel to dark fruit.
Carboy
A glass or plastic fermentation vessel with a narrow neck. Carboys are available in several capacities and require size-compatible stoppers or closures.
Chill Haze
A haze caused mainly by proteins and polyphenols that becomes visible when beer is cold and may disappear as the beer warms.
Chloride-to-Sulphate Ratio
A comparison of chloride and sulphate in brewing water. Brewers use it as one factor when adjusting the balance between malt fullness and hop dryness.
Closed Transfer
Moving beer between sealed vessels using pressure while limiting exposure to oxygen and outside contaminants.
Cold Crash
Rapidly cooling fermented beer to encourage yeast, hops and suspended particles to settle before packaging.
Cold-Side
The part of the brewing process after wort has been cooled. Cold-side equipment requires careful cleaning and sanitizing.
Conditioning
A period after primary fermentation during which beer matures, flavours develop and suspended material may settle.
Conversion
The enzymatic transformation of grain starch into fermentable and unfermentable sugars during the mash.
Crystal Malt
A type of caramelized specialty malt used to add colour, sweetness, body and caramel-like flavours. The terms crystal malt and caramel malt are often used interchangeably.

Brewing Terms: D–H

Decoction Mash
A traditional mash method in which part of the mash is removed, boiled and returned to raise the temperature of the main mash.
Dextrin
A complex carbohydrate that brewing yeast generally cannot fully ferment. Dextrins can contribute body and mouthfeel.
Diacetyl
A fermentation compound with a butter, butterscotch or buttery popcorn character. It is acceptable at low levels in some beer styles but considered a fault in others.
Diacetyl Rest
A controlled rise in fermentation temperature that encourages yeast to reduce remaining diacetyl before lagering or cold conditioning.
Diastatic Power
A measurement of a malt’s enzymatic ability to convert starch into sugar during mashing.
Dip Tube
A tube inside a kettle, fermenter or keg used to draw liquid from a selected point in the vessel.
DME (Dry Malt Extract)
Concentrated wort that has been dried into powder. Dry malt extract supplies fermentable malt sugar for extract brewing, yeast starters and recipe adjustments.
DMS (Dimethyl Sulphide)
A volatile compound often described as cooked corn, cabbage or vegetables. Vigorous boiling and proper cooling help reduce unwanted DMS.
Dough-In
The stage when crushed grain is mixed with strike water at the beginning of the mash.
Dry Hopping
Adding hops during or after fermentation to increase hop aroma and flavour without adding substantial kettle bitterness.
Dry Yeast
Brewing yeast produced in a dehydrated form for storage and convenient pitching. Some dry yeast may be pitched directly, while rehydration may be recommended for specific products.
EBC (European Brewery Convention)
A beer-colour scale commonly used in Europe. EBC values are approximately 1.97 times the corresponding SRM value.
Efficiency
A measurement of how much potential extract is recovered from grain. Mash efficiency and brewhouse efficiency measure different parts of the process.
Electric Brewing System
Brewing equipment that uses an electric heating element rather than a propane burner or stove. It may be a custom kettle system or an all-in-one brewing system.
Enzyme
A protein that speeds a biochemical reaction. Brewing enzymes help convert starch, break down complex carbohydrates or improve fermentation and clarification.
Ester
An aromatic fermentation compound that can produce fruity characteristics such as banana, pear, apple or stone fruit.
Extract Brewing
A brewing method that uses liquid or dry malt extract as the main source of fermentable malt sugar.
False Bottom
A perforated or screened platform that supports the grain bed while allowing wort to drain from a mash tun or brew kettle.
Fermentation
The process in which yeast converts fermentable sugars primarily into alcohol, carbon dioxide and flavour compounds.
Fermentation Temperature
The temperature of the fermenting beverage itself. Active fermentation can be warmer than the surrounding room or chamber.
Fermenter
A vessel used to hold wort, must or another beverage during fermentation.
FG (Final Gravity)
The specific-gravity reading taken when fermentation is complete. Final gravity helps estimate attenuation and alcohol content.
Finings
Ingredients used to help yeast, proteins, polyphenols or other suspended particles settle from beer, wine or cider.
Flocculation
The tendency of yeast cells to clump together and settle or rise after fermentation. Yeast strains may have low, medium or high flocculation.
Force Carbonation
Carbonating a beverage by applying pressurized CO2 in a sealed keg or tank.
Free Amino Nitrogen (FAN)
A group of nitrogen-containing compounds in wort that yeast uses for growth and fermentation.
Fusel Alcohol
A higher alcohol that can create hot, harsh or solvent-like flavours when present at excessive levels.
Gelatin
A fining agent used to help yeast and haze-forming particles settle from beer.
Grain Bed
The layer of crushed grain that forms in the mash tun and helps filter wort during recirculation and lautering.
Grain Bill
The complete list and quantity of malted and unmalted grains used in a brewing recipe.
Grain Crush
The degree to which malt is milled before mashing. A suitable crush exposes the grain interior while preserving enough husk material for wort flow.
Gravity
A measurement of liquid density compared with water. Brewers use gravity readings to track sugar concentration and fermentation progress.
Gravity Points
The digits after the decimal in a specific-gravity reading. A gravity of 1.050 contains 50 gravity points.
Gypsum
Calcium sulphate used to add calcium and sulphate to brewing water. Sulphate can emphasize hop bitterness and a drier finish.
Heating Element
An electrical component that converts electricity into heat. Brewing elements may mount through threaded, weldless or tri-clamp connections.
HERMS
Heat Exchanged Recirculating Mash System. Wort is circulated through a heat exchanger to maintain or raise mash temperature.
Hop Creep
Unexpected fermentation caused when enzymes introduced by dry hops break larger carbohydrates into fermentable sugars.
Hop Oil
Aromatic compounds in hops responsible for many floral, citrus, tropical, herbal, resinous and spicy hop characteristics.
Hop Stand
Holding hops in hot wort after the boil for a controlled amount of time to extract flavour and aroma.
Hop Utilization
The portion of hop alpha acids that isomerizes and contributes measurable bitterness to wort.
Hot Break
Proteins and other material that coagulate and form visible particles near the beginning of the wort boil.
Hot-Side
The portion of the brewing process before the wort is cooled, including mashing, lautering and boiling.
Hydrometer
An instrument that measures the density or specific gravity of a liquid. Comparing original and final gravity readings helps estimate fermentation progress and ABV.

Brewing Terms: I–M

IBU (International Bitterness Units)
A laboratory measurement of bittering compounds in beer. Perceived bitterness also depends on malt sweetness, alcohol, water chemistry and other recipe factors.
Induction Brewing
Heating a compatible brew kettle with an induction cooktop. A stainless steel kettle is not automatically induction compatible.
Infection
Unwanted microbial growth in wort or beer. Signs may include unexpected sourness, overcarbonation, unusual aroma or visible surface growth.
Irish Moss
A kettle fining derived from seaweed that helps proteins coagulate and settle from wort.
Isinglass
A traditional collagen-based fining used to help yeast settle from beer or wine.
Kettle Finings
Clarifying agents added during the boil to help proteins and other haze-forming material settle from wort.
Krausen
The foam and yeast layer that forms on top of actively fermenting beer.
Lactobacillus
A group of lactic-acid-producing bacteria used intentionally in some sour-beer fermentations.
Lag Phase
The early stage after yeast is pitched when cells adapt, absorb nutrients and begin multiplying before visible fermentation becomes vigorous.
Lager
Beer fermented with lager yeast and generally conditioned at cool temperatures. Lager yeast includes strains of Saccharomyces pastorianus.
Lagering
Conditioning beer at cold temperatures to encourage clarification and the development of a smooth fermentation profile.
Late Hop Addition
Hops added near the end of the boil to preserve more hop flavour and aroma than an early bittering addition.
Lautering
The process of separating sweet wort from the grain after mashing.
Lightstruck
An off-aroma created when hop compounds react with certain wavelengths of light. It is commonly described as skunky.
Liquid Yeast
A brewing yeast culture packaged in liquid form. Liquid yeast provides access to many specialized strains but may require careful storage or a yeast starter.
LME (Liquid Malt Extract)
Concentrated wort in syrup form used as a fermentable ingredient in extract and partial-mash brewing.
Lovibond (°L)
A scale commonly used to describe the colour of brewing malt and grain. Lower Lovibond values indicate pale malt, while higher values indicate darker malt.
Malt
Grain that has been germinated under controlled conditions and then dried or kilned. Malt supplies fermentable extract, colour, flavour and enzymes.
Malt Extract
Concentrated wort produced from malted grain. Malt extract is available as dry malt extract and liquid malt extract.
Mash
A mixture of crushed grain and water held at controlled temperatures so enzymes can convert grain starch into sugar.
Mash Efficiency
The percentage of potential grain extract recovered in the wort before the boil.
Mashout
Raising the mash temperature near the end of mashing to reduce wort viscosity and slow enzymatic activity before lautering.
Mash pH
The acidity of the mash. Mash pH affects enzyme activity, flavour, extraction and wort quality.
Mash Pipe
A removable perforated grain vessel used in many all-in-one electric brewing systems.
Mash Rest
A period during which the mash is held at a selected temperature to encourage specific enzymatic activity.
MCU (Malt Colour Units)
A simple calculation using malt weight, malt Lovibond and batch volume to estimate colour contribution before applying a beer-colour formula.
Milling
Crushing malted grain before mashing to expose the starchy interior while retaining useful husk material.
Mouthfeel
The physical sensation of beer in the mouth, including body, carbonation, creaminess, dryness, warmth and astringency.
Must
Unfermented juice or crushed fruit prepared for wine, cider or another fruit-based fermentation.

Brewing Terms: N–R

Original Gravity (OG)
The specific gravity of wort measured before fermentation. Original gravity indicates the concentration of dissolved material available before yeast begins fermenting.
Oxidation
A reaction caused by oxygen exposure that may create stale, papery, cardboard-like or muted flavours and shorten shelf life.
Partial-Mash Brewing
A brewing method that combines a small mash of grain with dry or liquid malt extract.
PBW
Powdered Brewery Wash, an alkaline cleaner used to remove organic brewing residue from compatible equipment. PBW is a cleaner, not a sanitizer.
Pectic Enzyme
An enzyme used to break down pectin in fruit. It can improve juice extraction and reduce pectin haze.
Pellet Hops
Hop material that has been milled and compressed into pellets for storage and brewing use.
Phenol
A flavour or aroma compound that may present as spicy, clove-like, smoky, medicinal or plastic-like. Some yeast-derived phenols are desirable in specific beer styles.
Phosphoric Acid
An acid commonly used to lower brewing-water or mash pH with relatively little flavour contribution when used correctly.
Pitching
Adding yeast to cooled wort or another prepared fermentation medium.
Pitching Rate
The quantity of viable yeast cells added relative to the wort volume and gravity.
Polyphenol
A group of compounds found in malt, hops and other plant material. Polyphenols can affect flavour, astringency, stability and haze.
Primary Fermentation
The main active stage of fermentation when yeast converts most fermentable sugar into alcohol and carbon dioxide.
Priming Sugar
A measured amount of fermentable sugar added before packaging to produce natural carbonation in sealed bottles or kegs.
Pressure Fermentation
Fermentation performed in a pressure-capable vessel. Pressure can affect yeast behaviour, ester production and carbonation.
Protein Rest
A mash rest that encourages proteolytic enzymes to break down proteins. It may be useful for specific grain bills but is not required for every recipe.
Recirculation
Moving wort from below the grain bed back over the top of the mash to improve temperature consistency and wort clarity.
Refractometer
An optical instrument that estimates dissolved-solids concentration from refracted light. Fermenting samples require an alcohol correction for accurate gravity estimates.
Residual Alkalinity
An estimate of how brewing-water minerals may affect mash pH after considering alkalinity, calcium and magnesium.
Residual Sugar
Sugar remaining in a beverage after fermentation. Residual sugar can affect sweetness, body and stability.
Reverse Osmosis Water
Water treated by reverse osmosis to remove most dissolved minerals. Brewers can use it as a low-mineral starting point for building a water profile.
Rice Hulls
Non-fermentable husk material added to a mash to improve wort flow, especially in recipes containing wheat, rye, oats or finely crushed grain.
RIMS
Recirculating Infusion Mash System. Wort is pumped through a directly heated tube or chamber to control mash temperature.

Brewing Terms: S–Z

Saccharification Rest
The mash stage during which enzymes convert grain starch into fermentable and unfermentable sugars.
Sanitizer
A product used on previously cleaned surfaces to reduce microorganisms to an acceptable level. Sanitizer does not replace proper cleaning.
Secondary Fermentation
A loosely used term for transferring beer to another vessel for conditioning or for a genuine additional fermentation caused by new fermentable ingredients.
Sediment
Yeast, proteins, hop material and other particles that settle at the bottom of a fermenter, bottle or keg.
SG (Specific Gravity)
The density of a liquid compared with water. Brewers use specific-gravity readings to monitor wort strength and fermentation.
Sparging
Rinsing the grain bed with brewing water after or during lautering to recover additional fermentable extract.
Specialty Malt
Malt used mainly to add colour, flavour, aroma or body rather than serve as the primary source of fermentable extract.
Specific Gravity
A ratio comparing the density of wort or beer with the density of water at a specified temperature.
Spunding
Controlling fermentation pressure with an adjustable pressure-relief valve. Spunding may retain carbonation produced during fermentation.
SRM (Standard Reference Method)
The scale commonly used in North America to describe the colour of finished beer. Low SRM values represent pale beer, while high values represent dark beer.
Stalled Fermentation
A fermentation that stops before reaching the expected final gravity. Possible causes include temperature, yeast health, nutrient availability or unfermentable wort composition.
Starter Wort
Low-gravity wort used to grow an active yeast culture before it is pitched into the main batch.
Steeping Grain
Specialty grain soaked in warm water to extract colour and flavour without performing a complete mash.
Step Mash
A mash schedule that uses two or more temperature rests to encourage different enzymatic activities.
Strike Water
Brewing water heated to a calculated temperature before being mixed with crushed grain to begin the mash.
Stuck Mash
A mash in which wort flow through the grain bed becomes extremely slow or stops.
Sulphate
A brewing-water ion that can emphasize hop bitterness and dryness. Excessive levels may create a harsh mineral character.
Tannin
A polyphenolic compound found in grain husks, hops, fruit skins, seeds and oak. Excessive extraction can produce astringency.
Temperature Controller
A device that switches heating or cooling equipment to maintain a selected temperature range.
Terminal Gravity
The stable gravity reached when fermentation has consumed the available fermentable sugars under the existing conditions.
Trub
Hop material, proteins, lipids and other sediment that collects in the brew kettle or fermenter.
Vorlauf
Recirculating the first wort drawn from a mash tun back over the grain bed until the runoff becomes clearer.
Volumes of CO2
A measurement of dissolved carbon dioxide. One volume means one equivalent volume of CO2 dissolved in one volume of liquid.
Water Profile
The mineral composition of brewing water, commonly including calcium, magnesium, sodium, chloride, sulphate and bicarbonate.
Whirlpool
Circular movement of wort used to collect trub and hop material near the centre of a brew kettle after boiling.
Whirlpool Hop Addition
Hops added after the boil while the wort remains hot to extract hop flavour and aroma with controlled bitterness.
Whirlfloc
A tablet-form kettle fining used to help proteins and haze-forming particles coagulate and settle.
Whole-Cone Hops
Dried hop cones used in their natural form rather than being milled and compressed into pellets.
Wort
The sweet, unfermented liquid produced from malt or malt extract before yeast converts it into beer.
Wort Chiller
A heat exchanger used to cool hot wort after boiling. Common types include immersion, counterflow and plate chillers.
Yeast
A microorganism that converts fermentable sugar into alcohol, carbon dioxide and flavour compounds.
Yeast Nutrient
A source of nitrogen, minerals, vitamins or other compounds used to support yeast health and fermentation.
Yeast Propagation
Growing yeast under controlled conditions to increase the number of viable cells available for fermentation.
Yeast Starter
A small batch of low-gravity wort used to increase yeast-cell count and confirm activity before pitching.

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Understanding brewing terminology makes it easier to compare brewing equipment, follow recipes and troubleshoot fermentation. Explore brewing grain, hops, yeast, fermenters, brew kettles, electric brewing systems and testing equipment for your next batch.

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