I have a lot of friends that don't brew, along with a few that do. The ones that don't often get very confused very quickly when I say things like "The strike water was perfect, but the mash came out a little on the low side around 154." Or "I think I might need to sparge this next batch." So I decided I would compile a glossary of brewing terms.
This is not intended to be a complete glossary by any means. This is intended to expand upon terms that I find myself using, that the normal non-brew fanatic may not understand. For a more comprehensive and perhaps detailed glossary, see the How To Brew glossary.
Strike Water: Water heated to the desired temperature for mashing. Typically 6-12F higher than mash target temp depending on grain weight, grain temperature, desired mash temperature, and volume of water for mashing.
Mash: Steeping of milled grains to extract fermentable sugars, making it into wort. Typically done between 148-158F.
Wort: Malt-sugar solution you get from mashing.
Sparge: The process of rinsing sugar from the grain after the mash.
Grist: The milled grain to be used for a given recipe.
Specific Gravity/Brix: Ways to measure the amount of sugar present in the liquid wort/beer. In the USA here you're most likely to encounter SG, but here is an easy Brix to SG converter. You may see SG represented as OG or FG. These mean Original Gravity, and Final Gravity respectively. These are the start and end Specific Gravity values for a given brew, and by using these numbers along with an Alcohol By Volume calculator you can determine alcohol content.
Primary: Will typically appear as "in primary" or "during primary." What this means is the initial vessel where the bulk of fermentation happens.
Secondary: Again, will typically appear as "in secondary" or "during secondary." This is (as you may have now guessed) the second vessel that the beer is racked to. This is not strictly necessary, though for fruit or other additions after primary completes it is nice to have the option to secondary.
Racking: To move the wort or beer from one vessel to another.
Floc/Flocculation: To cause to group together. In the case of yeast, more flocculant strains drop out of suspension and result in a clearer beer. To "floc out" means essentially to drop out of suspension. To clarify the final product.
Whirlfloc: A product that helps drop protein matter from the hot/cold break out of suspension at the end of the boil. Results in clearer final product.
Hot Break: Proteins that coagulate and fall out of suspension during the boil. You'll notice it at the start of the boil as a frothy layer on top of the liquid until the boil really gets going.
Cold Break: As you may have guessed, this is the opposite of hot break. These proteins will fall out of suspension when the wort is rapidly chilled to yeast pitching temperatures. Not nearly as fun to watch as the hot break, but very important for a clear final product.
HLT: Hot Liquor Tank. Fancy name for a vessel that heats water.
BK: Boil Kettle. Self explanatory. I hope.
FWH: First Wort Hops. These are hops added after the mash and before the boil. For more information, see: this beersmith article.
HERMS: Heat Exchanging Recirculating Mash System
RIMS: Recirculating Infusion Mash System