CBI Apprentice cheat sheet

Ale vs. lager is defined by yeast type and fermentation temperature, not color: ales use top-fermenting Saccharomyces cerevisiae at roughly 16-24 C; lagers use bottom-fermenting Saccharomyces pastorianus at roughly 7-13 C.

Bitterness is measured in IBU (International Bitterness Units), where 1 IBU = 1 mg/L of isomerized alpha acids; a typical lager sits near 10-20 IBU and a double IPA can exceed 60-100 IBU.

Color is measured in SRM (Standard Reference Method) or EBC; EBC is approximately SRM x 1.97, so a 10 SRM amber is about 20 EBC.

Original gravity (OG) measures fermentable sugar density before fermentation and final gravity (FG) after; apparent attenuation percent = (OG - FG) / OG x 100.

Alcohol by volume can be estimated as ABV = (OG - FG) x 131.25 when gravity is read in specific gravity points.

Roasted barley and black malt contribute color and roast flavor but little fermentable extract; crystal/caramel malts contribute unfermentable dextrins that raise body and residual sweetness.

Hop aroma compounds (myrcene, humulene, linalool) are volatile and are largely driven off by long boils; late and whirlpool additions preserve aroma while early additions drive bitterness.

Style families to recognize: pale lagers and pilsners, wheat beers (hefeweizen, witbier), pale ales and IPAs, stouts and porters, Belgian ales (saison, dubbel, tripel), and sour/wild ales.

Base malts (pale, pilsner, Munich, Vienna) have enough diastatic enzyme power to convert their own starch plus adjuncts; specialty malts generally lack the enzyme power to self-convert and must be mashed with a base malt.

Mash pH target is roughly 5.2-5.5 at mash temperature; residual alkalinity of brewing water is the key driver, and high alkalinity must be neutralized with acid or by adding calcium salts.

Brewing water ions matter: calcium aids enzyme activity and yeast flocculation, sulfate accentuates hop bitterness, chloride rounds malt sweetness, and magnesium supports yeast but tastes harsh above roughly 40 ppm.

Hop alpha acids are not bitter until isomerized by heat; utilization rises with boil time and wort gravity falls, so high-gravity brews need more hops per unit of bitterness.

Hop beta acids contribute little bitterness in the kettle but oxidize to bitter compounds during storage, which is why old hops can taste harsh and cheesy.

Yeast pitching rate, oxygenation of wort, and fermentation temperature determine ester and fusel production; underpitching and warm fermentation increase fruity and solventy off-flavors.

Yeast flocculation and attenuation are strain traits: a high-attenuation strain leaves low FG and a dry finish, while a low-attenuation strain leaves residual sweetness and body.

Adjuncts such as rice, corn, and sugar lighten body and color; unmalted grains and raw cereals need a cereal cooker or sufficient enzyme power from the base malt to convert.

Milling should crack the husk while keeping it largely intact to form a filter bed; excessive flour causes slow lautering and stuck mashes.

Mash rests: roughly 62-65 C favors beta-amylase for fermentable sugars and a drier beer; roughly 70-72 C favors alpha-amylase for dextrins and a fuller body.

Mash-out near 76-78 C denatures enzymes and lowers wort viscosity before lautering; sparge water above roughly 78 C risks extracting harsh tannins from husks.

The kettle boil is typically 60-90 minutes: it sterilizes wort, isomerizes alpha acids, drives off DMS precursors, and coagulates proteins into hot break.

Whirlpool separates trub from wort; rapid chilling after whirlpool promotes cold break and reduces DMS reformation and chill haze precursors.

Fermentation temperature control matters most in the first 48-72 hours; diacetyl rest near the end of primary fermentation lets yeast reabsorb diacetyl before cooling.

Dry hopping adds hop aroma without bitterness; it is done in the cellar at cool temperatures to limit extraction of harsh polyphenols and vegetal notes.

CIP (clean-in-place) requires correct chemical concentration, temperature, contact time, and flow velocity; verification is by visual inspection plus ATP swabs or microbiological plating.

Dissolved oxygen is the leading cause of staling; targets are typically below 50 ppb in finished beer, and packaging is the largest oxygen pickup point.

Carbonation is measured in volumes of CO2; most ales sit near 2.2-2.7 volumes and lagers near 2.5-2.8, with wheat beers and Belgian styles often higher.

Lightstruck (skunky) flavor comes from riboflavin-mediated photodegradation of iso-alpha acids; brown glass and cans block the damaging wavelengths while green and clear glass do not.

Chill haze is reversible protein-polyphenol haze that redissolves on warming; permanent haze does not clear and indicates colloidal instability.

Trans-2-nonenal is the classic cardboard/stale flavor of oxidized beer; other markers include sherry-like aldehydes and loss of fresh hop aroma.

Diacetyl (buttery) and acetaldehyde (green apple) are fermentation off-flavors; both can be reduced by giving yeast time and warmth before packaging.

Beer should be stored cold and dark; every 10 C rise in storage temperature roughly doubles the rate of staling reactions.

Packaging quality checks include fill height, seam or crown integrity, dissolved oxygen, CO2 levels, and microbiological stability testing.

Draught balance: applied pressure must overcome gravity and line resistance, so the required pressure in psi equals the static lift in feet x 0.5 plus line resistance, with a target of roughly 1 psi per foot of 3/16-inch line.

Dispense temperature should match the beer's carbonation: warmer beer needs higher applied pressure to hold CO2 in solution, and cold beer at excessive pressure foams.

CO2/nitrogen blends are used for stouts and long-draw systems; pure CO2 on a long line overcarbonates the beer, so a gas blend with lower CO2 proportion is used.

FOB (foam-on-beer) valves stop beer flow when the keg empties and prevent foam from being pushed into the line; they must be reset after a keg change.

Keg couplers are type-specific (D, S, A, G, U) and mismatched couplers cause leaks or no flow; the gas line goes to the gas port and the beer line to the liquid port.

Line cleaning should occur at least every two weeks with an approved line-cleaning chemical, followed by thorough water rinse; beer line residue harbors wild yeast and bacteria.

Glycol-cooled long-draw systems require balanced pressure and temperature along the entire run; warm spots cause breakout and foam even if the keg is cold.

A properly poured pint has a head of roughly 1-1.5 inches; excessive foam, flat beer, or cloudy pours point to temperature, pressure, or cleanliness faults.

CO2 is an asphyxiant: it is heavier than air and accumulates in cellars and fermentation rooms, so confined spaces require gas monitoring and ventilation before entry.

Caustic (sodium hydroxide) and acid cleaners are corrosive; PPE includes chemical goggles, face shield, gloves, and apron, and acid must never be added to caustic without control because the reaction is violent.

Never mix chlorine bleach with acid or ammonia; the reaction releases toxic chlorine or chloramine gas.

Sanitizers must contact a clean surface for the labeled contact time; organic soil inactivates sanitizer, so cleaning must precede sanitizing.

Hot water and steam cause scalds; wort and mash temperatures above 60 C can burn, and pressurized vessels and kegs must be vented before opening.

In the US, TTB regulates brewery permits, label approvals, and tax determination; state and local authorities separately license and inspect premises.

Alcohol beverage labeling must include the government warning statement, net contents, alcohol content where required, and the name and address of the bottler or producer.

Serving alcohol requires checking identification and refusing service to visibly intoxicated persons; dram-shop and liquor liability laws place responsibility on the licensee and its staff.