An off flavor in beer that causes cheesy, rancid, putrid, and baby vomit-type flavors at concentrations above its beer flavor threshold.

Geosmin is considered an off-flavor in beer and is cause by contaminated brewing liquor, rinse liquor, or dilution liquor.

Generally, esters are fruity and usually desirable, whereas phenols are spicy and usually undesirable. 

A method of fermentation by which all microorganisms necessary for fermentation are naturally occurring in the brewery and the brewer adds no cultures of microorganisms.

"Trappist" is an appellation (i.e. a legal description with the enforceability of a trademark) meaning that only brewers who meet certain requirements are allowed to use the Trappist name. 

Orthonasal and retronasal olfaction send messages to your brain to tell it what you are eating or drinking. While you can taste five basic tastes (sweet, sour, bitter, salty, and umami), you can distinguish thousands of volatile chemical compounds.

The fullness or thickness of a beer on the tongue and palate. Body is part of mouthfeel, which is the tactile sensation beer produces in the mouth. Body is one of the physical qualities of a beer.

Alternative sources of extract used to replace a proportion of malt in a beer. Adjuncts can be liquid or solid. Familiar adjuncts include sugars, wheat, corn, rice, oats, sorghum, and millet. 

A sour, fruity, red wine-like Belgian ale, known as the Burgundy of Belgium. It is more wine-like than any other beer style.

A person who conducts others through the world of fine beer and has completed the exams and requirements of the Cicerone Certification Program. There are four levels of Cicerone certification: Certified Beer Server, Certified Cicerone, Advanced Cicerone, and Master Cicerone.