Brewing Glossary

Our home brewing glossary is your guide to beer terminology, ingredients and techniques. Our instructions refer to things like SRM, DME, gravity, priming sugar and more. In our home brewing glossary, we provide definitions and details about these common homebrewing terms.

Alcohol by volume. A standard measure of how much alcohol is contained in an alcoholic beverage. To calculate the precise ABV of your homebrewed beer, use a hydrometer. Samples of beer taken before & after fermentation are compared to calculate the ABV.

A technique used to create an oxygen-rich environment for yeast prior to pitching yeast to start fermentation. Can be done simply by sealing the carboy with a rubber stopper, covering the hole and shaking the wort vigorously for 60+ seconds. NOTE: This is the ONLY point in the homebrew process where oxygen is welcome, because it helps yeast grow & reproduce quickly. After fermentation begins, you should avoid introducing any oxygen or air bubbles to the fermenter.

An airlock allows CO2 to escape the fermenter, while keeping oxygen out. The airlock is filled with a small amount of water, sanitizer or even a neutral spirit, which provides a barrier that gas can escape from, but oxygen can’t penetrate. If your fermenter is a carboy, the stopper will fit in a rubber stopper and the stopper into the carboy neck. Some fermenters may have a lid with a hole specifically for the airlock. If your fermenter has little headspace, a blow off is recommended for the first few days of fermentation. After fermentation activity calms and krausen falls, you can replace the blow off tube with the airlock.

The primary source of bitterness from hops. The lupulin, found inside the hop cone, contains the coveted resins and oils. They contribute bitterness when isomerized in boiling wort. So, the longer you boil hops the more bitterness the hops will contribute. Alpha Acids are sensitive to light and will “skunk” a beer if exposed. This is why beer’s traditionally bottled in amber glass.

Hops that are added late in the boil in order to extract aromatic qualities. Specifically, at 2 minutes left in the 60 minute boil. Not every Craft a Brew beer recipe will feature an Aroma hop addition. Hops added this late in the boil are exposed to less heat, which limits the extraction of harsh, bitter oils. Instead, the aromatic qualities of the hops are retained in the wort.

Refers to the conversion of sugars into alcohol during fermentation. Usually described as a percentage. A high attenuating yeast strain - like a Belgian yeast - will consume more wort sugars, produce more alcohol & exhibit a drier finished beer. Low attenuating yeast strain - like Fermentis S-04 English Ale Yeast - in the same wort (unfermented beer) will consume less sugar during fermentation, resulting in a sweeter taste, fuller body and more residual sugars left in the beer.

Hops that are added at the very beginning of the boil in order to extract volatile, bitter hop oils for 60 minutes. Specifically, Bittering hops are added to boiling wort and then you start your 60 minute boil timer. Most Craft a Brew beer recipes will feature some amount of Bittering hops. Most hop varieties can be used as a “Bittering” addition, but certain varieties are favored for their high alpha acid content.

A blow off is recommended in fermenters with little headspace. Using sanitized vinyl transfer tubing, insert one end into the rubber stopper and the other end into a half-full glass of water. This serves the same function as an airlock and provides an ‘escape route’ for excess foam, CO2 and solids that can spill out of an airlock during peak fermentation activity. Once fermentation activity has calmed down, you can replace your blow off tube with an airlock for the rest of fermentation.

A term for overcarbonated bottles of homebrew that explode, usually caused by one of four things. 1) too much priming sugar, 2) bottling too early, 3) bottling too long, 4) infection. Bottle bombs are extremely dangerous. If a bottle has exploded, the rest of the batch should be handled with extreme caution. Protective eyewear, a thick jacket & towels should be used to either discard the bottles OR store them in the fridge.

A technique for naturally carbonating a beer. Priming Sugar is added to fermented beer to help it “re-ferment” in bottles. The yeast in the beer will convert the added sugar into CO2 in sealed bottles. Most beers will bottle condition for 2 weeks at room temperature. After conditioning, bottles should be refrigerated to lock in the carbonation and to prevent bottle bombs. Bottle conditioning also helps refine a beer’s complex flavors.

Hops that are added directly to the fermenter to extract aroma & flavor  without adding bitter qualities. Because no volatile hop oils are boiled off, you’ll retain as much flavor and aroma as possible. Some Craft a Brew recipes feature a Dry Hop addition, like our New England IPA, Hoppy Wheat & Black IPA.

DME is wort (unfermented beer) that has undergone evaporation, meaning nearly all the water content is removed. DME powder is the foundation of Craft a Brew’s recipes. It provides the base malts and a bulk of the fermentable sugars. Specialty steeping grains are used with DME to provide flavors, colors and other qualities to the beer (like head retention, acidity, etc.)

The process in which yeast converts sugars into alcohol and carbon dioxide.

Hops that are added at the very end of the boil once your pot is off the burner (refers to the “flame” going out on a gas burner). This timing takes advantage of the fleeting heat from the boil and preserves aromatics and fruity flavors of the hops. Because the boil is over and the wort goes right into an ice bath, there’s no opportunity for the hops to undergo a bittering transformation.

Hops that are added with 10-15 minutes left in the boil, but the timing can vary per the recipe. When added at this time, fewer bitter oils are extracted. Instead, the hops contribute the hop variety’s flavor notes. This can include citrus, stone fruit, spice, floral and other notes depending on the hop.

Refers to the ability of yeast cells to clump together. Different yeast strains will exhibit different degrees/levels of flocculation. A HIGH flocculating yeast strain - like LalBrew BRY-97 - will clump together quite well, helping the cells fall out of suspension for better clarity. High attenuation also produces crisper, cleaner tasting beers.A LOW flocculating yeast strain - like WB-06 yeast for Hefeweizens - will remain suspended in beer, often creating a hazier appearance. Low flocculation can result in a more complex flavor profile.

Hops that are added to wort 1) after the boil and 2) once it has naturally cooled to 180ºF. The hop pellets “stand” in the wort for 30 min” while the temperature naturally cools. After 30 minutes, the wort is chilled to prepare it for yeast. The temperature conditions during a Hopstand addition prevents flavor and aroma from evaporating, retaining them in the beer. The lower temperature prevents the isomerization of bitter hop oils.

A tool for calculating the precise ABV of your beer, wine, mead or hard cider. A hydrometer measures the sugar content in a sample of liquid before fermentation and again after fermentation. These are called original gravity (OG) & final gravity (FG) readings.

The International Bittering Units (IBU) scale provides a measure of bitterness of beer, which is provided by the hops used in the brewing process. Light ales typically have IBU ratings between 10-20 while highly hopped Imperial IPAs can have IBU ratings between 60-100.

The heady foam that forms during peak fermentation in a beer. As CO2 is created during fermentation, it pushes spent hops, dead yeast cells, malt tannins, proteins & other particulates up to the top of the fermenter and a bubbly foam forms. Krausen is a sign that yeast and fermentation are active & healthy. It billows up during peak fermentation and eventually will dissipate, leaving a ring inside the fermenter.

Refers to the degradation of beer due to oxygen exposure. Oxidation can happen when beer is exposed to oxygen or air bubbles during fermentation or during bottling. Oxidation can create unwanted off-flavors in the finished beer (described as “stale” or like “wet cardboard.”).

Sugar that is added to fermented beer in preparation for bottle carbonation. The yeast suspended in the beer will convert this added sugar into CO2 to carbonate the beer. Brewers often use Dextrose, White Table Sugar, Carbonation Drops or even DME as priming sugar.

Refers to transferring beer from one vessel to another. This is done to separate beer from sediment and to reduce oxygen exposure. This is done with a racking cane or auto-siphon & transfer tubing.

The Standard Reference method (SRM) is a scale that brewers use to measure and quantify the color of a beer. The higher the SRM is, the darker the beer.

Pronounced “troob,” trub is the layer of sediment that collects during fermentation. The trub settles at the bottom of the fermenter and consists of fats, proteins, spent hops, dead yeast cells, etc.

Yeast is a living organism that’s technically a fungus. It grows and multiplies by “eating” sugars from malt, converting sugar into alcohol during fermentation. Yeast will also help carbonate your beer in bottles by releasing CO2. Different strains of yeast will lend different character to your homebrewed beer - fruity, spicy, dry, etc. Each yeast strain has a different tolerance to the alcohol that it creates. Eventually yeast will die in the presence of alcohol, which stops the fermentation process.