CBI Apprentice key terms

The density of unfermented wort measured before yeast is pitched, expressed as specific gravity or degrees Plato. It indicates how much fermentable sugar the brewer extracted from the malt and predicts the beer's potential alcohol.

The density of beer measured after fermentation is complete. Comparing it with original gravity shows how much sugar the yeast consumed and lets the brewer calculate alcohol content and residual sweetness.

The percentage of fermentable sugar that yeast converts to alcohol and carbon dioxide. High attenuation yields a drier, thinner beer; low attenuation leaves residual sweetness and more body in the finished product.

The percentage of a beer's volume that is ethanol. In the US it is calculated from the difference between original and final gravity, and it must appear on labels for most packaged beer.

A scale expressing the concentration of dissolved solids, mainly sugars, in wort as grams per 100 grams of solution. Brewers use it alongside specific gravity to measure strength and monitor fermentation.

A calibrated glass float used to read the specific gravity of wort or beer. A sanitized sample is placed in a cylinder and the reading taken at the meniscus, correcting for temperature.

Barley or other grain that has been steeped, germinated, and kiln-dried so its starches can be converted to sugar during mashing. Malt supplies color, flavor, body, and most of the fermentable extract.

The pale malt that makes up the bulk of a grain bill and provides most of the fermentable sugar and enzyme activity. Examples include standard two-row pale malt and pilsner malt.

Malted grain processed to add character rather than fermentable extract. Crystal, chocolate, and roasted malts contribute color, caramel or roast flavor, and body and are used in smaller proportions.

A measure of a malt's enzyme content, chiefly alpha- and beta-amylase, available to convert starch to sugar. Highly modified base malts have enough; heavily roasted malts have little or none.

The process of mixing crushed malt with hot water so enzymes convert starch into fermentable sugars. Temperature and pH during the rest determine the sugar profile and body of the resulting wort.

Separating the sugary liquid wort from the spent grain bed after mashing. The brewer recirculates until the runoff is clear, then sparges with hot water to rinse remaining sugars.

Rinsing the grain bed with hot water during lautering to recover sugars left behind after the first wort runnings. Over-sparging can extract harsh tannins and raise wort pH.

The vessel where crushed malt and hot water are combined and held at target temperatures for enzymatic conversion. Many brewhouses use a combined mash-lauter tun with a false bottom to hold the grain bed.

The sweet, unfermented liquid produced by mashing and lautering. After boiling with hops and cooling, wort is pitched with yeast and becomes beer through fermentation.

The vigorous heating of wort, typically 60 to 90 minutes. It sterilizes the wort, drives off unwanted volatiles, coagulates proteins, and isomerizes hop acids to create bitterness.

The coagulation and precipitation of proteins and polyphenols that occurs when wort boils vigorously. Removing this trub before fermentation improves clarity and flavor stability.

A vessel or stage after the boil where wort is stirred into a rotating motion so solids settle into a cone at the center. It also allows late hop additions that add aroma without much bitterness.

A specific genetic variety of brewing yeast selected for its fermentation behavior and flavor output. Ale strains ferment warm and produce fruity esters; lager strains ferment cool and produce clean, crisp beer.

Ale yeast that ferments at warmer temperatures, roughly 15 to 24 degrees Celsius, and rises to the surface at the end of fermentation. It typically produces fruity esters and a fuller flavor profile.

Lager yeast that works at cooler temperatures, roughly 7 to 13 degrees Celsius, and settles to the bottom of the fermenter. It ferments slowly and cleanly, producing crisp, neutral beer.

The number of viable yeast cells added per volume of wort, usually expressed in million cells per milliliter. Pitching too little stresses yeast and causes slow, incomplete fermentation and off-flavors.

The metabolic process in which yeast converts sugars in wort into alcohol, carbon dioxide, and flavor compounds. Brewers control temperature and oxygen to steer the outcome and avoid off-flavors.

A buttery, butterscotch-flavored compound produced during fermentation and normally reabsorbed by yeast near the end. Elevated levels signal incomplete fermentation or premature cooling and are considered a defect in most styles.

Cold conditioning of lager beer at near-freezing temperatures for weeks after primary fermentation. It clarifies the beer, smooths sulfur compounds, and rounds out flavor before packaging.

The cone-shaped flowers of the hop plant, used in brewing to add bitterness, flavor, and aroma. Hop acids also help preserve beer and improve foam retention.

The main bittering compound in hops, measured as a percentage of hop weight. It isomerizes during the boil into iso-alpha acids, which give beer its measured bitterness.

A standard measure of beer bitterness, equal to parts per million of iso-alpha acids. Higher values taste more bitter, though malt sweetness and carbonation affect perception.

Adding hops after fermentation, or late in it, to extract aroma without adding much bitterness. It delivers fresh, pungent hop character but raises the risk of contamination and grassy notes if left too long.

A numerical scale describing beer color, from about 2 for pale straw to 40 or more for black. It is measured by light absorbance and used to judge whether a beer matches its style.

Published reference descriptions of recognized beer styles, giving ranges for color, bitterness, gravity, and alcohol plus typical aroma and flavor. They are used in judging and product development.

Any aroma or taste that departs from the intended character of a beer, such as diacetyl, wet cardboard, or cooked vegetables. Off-flavors usually trace to ingredients, sanitation, oxygen, or fermentation faults.

Chemical reaction of beer with oxygen that produces stale, cardboard or sherry-like flavors and darkens color. It is slowed by minimizing oxygen pickup during transfers, packaging, and storage.

Oxygen present in beer, measured in parts per billion. Levels should be kept very low after fermentation because even small amounts accelerate staling and shorten shelf life.

The period during which a packaged beer keeps its intended flavor and appearance under normal storage. It depends on oxygen pickup, pasteurization or filtration, packaging quality, and storage temperature.

Keeping beer at cold temperatures continuously from packaging through storage and delivery to the point of sale. It slows staling and preserves hop aroma, especially for unpasteurized or dry-hopped beers.

An automated system that circulates cleaning and sanitizing solutions through tanks, pipes, and fillers without disassembly. Correct flow, temperature, concentration, and contact time are required for it to work.

Reducing microorganisms on brewing surfaces and equipment to levels that will not spoil beer. It follows cleaning, since sanitizer cannot penetrate soil, and is verified by ATP or microbiological testing.

Cleaning with a hot sodium hydroxide solution that dissolves organic soils such as protein and hop residue. Brewers follow it with an acid rinse to remove beerstone and neutralize remaining caustic.

A hard calcium oxalate deposit that builds up on tank and line surfaces. It shelters microbes and must be removed with acid cleaning, since ordinary caustic cycles will not dissolve it.

Regular flushing of dispense lines with a cleaning solution to remove yeast, bacteria, and beerstone. Neglect causes off-flavors, foaming, and quality complaints, so most operators clean lines on a fixed weekly schedule.

The fitting that attaches a keg to the dispense system, sealing the keg valve and connecting gas and beer lines. Types include the US Sankey D and European designs, and they are not interchangeable.

A device on a draught line that stops beer flow when a keg empties, preventing foam from entering the line. It saves beer, reduces waste, and keeps the next pour from arriving as foam.

The gas used to pressurize kegs and push beer through draught lines. Correct pressure balances line resistance and keeps beer carbonated; excessive pressure causes foaming and flat pours.

A blend of carbon dioxide and nitrogen used for draught dispense, often around 70 percent nitrogen and 30 percent carbon dioxide. It keeps highly carbonated beers from over-foaming and suits long line runs.

How long a beer's head persists after pouring. It depends on protein and hop content, correct carbonation, clean glassware, and dispense pressure, and it is a visible indicator of beer quality.

The mineral content of brewing water, especially calcium, magnesium, sulfate, and chloride. Sulfate emphasizes hop bitterness while chloride rounds malt sweetness, so brewers adjust water to suit each style.

The acidity of the mash, ideally around 5.2 to 5.4. It controls enzyme activity, sugar extraction, and how harsh hop bitterness tastes, and brewers adjust it with acid or mineral additions.

Heating packaged or bulk beer to kill spoilage organisms and extend shelf life. Flash pasteurization treats beer in a heat exchanger; tunnel pasteurization heats sealed bottles or cans.

Passing beer through a membrane fine enough to remove yeast and bacteria without heat. It delivers microbiological stability but can strip some aroma and body if the filter is too tight.

The US federal agency that regulates brewing permits, label approvals, and tax reporting for beer. Brewers must obtain approval for labels and keep records of production and removals.

A preventive food-safety system that identifies hazards, sets critical control points, and defines monitoring and corrective actions. Breweries use it for packaging, cleaning, and chemical handling.

A document listing a chemical's hazards, safe handling, protective equipment, and first aid. Employers must keep one available for every hazardous chemical used, such as caustic, acid, or sanitizer.

An enclosed area with limited entry and exit that is not designed for continuous occupancy, such as a fermenter or tank. Entry requires a permit, gas testing, an attendant, and rescue planning.

Aromatic compound formed during fermentation that smells fruity, like banana, pear, or apple. Esters are desirable in many ale styles but can be a defect when excessive or unexpected for the style.