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Original Gravity

July 16, 2013 / / 0 Comments

Original gravity or OG is the specific gravity reading of a beer’s wort prior to having the yeast pitched for fermentation. The original gravity reading is important because it gives the brewer an idea of how much sugar is available for fermentation and what the approximate alcohol by volume will be once fermentation completes. The original gravity reading also permits a brewer to calculate his or her brew house efficiency to determine what percentage of starches and sugars were extracted from the grain bill used to make the beer. Typically either a hydrometer or refractometer are used to take the original gravity reading.

 

Below is the photo of a hydrometer which is used to take original gravity readings.

Beer Hydrometed, Final Gravity Reading

Oxidation

July 16, 2013 / / 0 Comments

Oxidation is the degradation or modification of beer when it comes in contact with oxygen or an oxidizing agent. Oxidization in beer is inevitable and occurs in beer at all times regardless of how it is stored. That being said, there are ways to diminish the rate of beer oxidation.

A good rule of thumb is to prevent oxygen from coming in contact with your beer whenever possible. The only time that oxygen should intentionally be introduced to a beer is when aerating or oxygenating wort prior to pitching yeast, and, in rare cases, to facilitate a souring process. Great caution should be taken when transferring, racking, kegging, and bottling beer to avoid splashing it or exposing it to more oxygen then is necessary.

When possible, fermentation vessels, kegs and bottles should be purged with CO2 prior to and after having beer transferred into them. Heat is another factor that impacts oxidation, and, whenever possible, beer should be stored cold to reduce oxidation rates and to preserve its freshness. Another way to help slow the impact of oxidation is to keep bottles and fermenters shielded from sunlight.

 

Beer that has been oxidized typically has a stale or paper-like taste.  In darker beers, you may also smell or taste sherry notes.

 

Lautering

July 14, 2013 / / 0 Comments

Lautering is a brewing process where hot water (typically heated to 168-170° F) is used to flush the sugars from the crushed grains after the mash has completed. Once flushed from the grains, the hot water and sugars are then transferred from the mash tun or lauter tun.

kilning

July 13, 2013 / / 0 Comments

Kilning is the process of drying malted grain in a kiln using an indirect heat source to halt germination and evaporate much of the moisture from the malted grains. Kilning grain started to become popular in the early 18th century and was the predominant method for drying malt by the 19th century. Prior to kilning, malt was often dried over open flame which would impart a smoke flavor in the finished beer, similar to what you may find today in a German rauchbier.

Infusion Mashing

July 12, 2013 / / 0 Comments

Infusion mashing is the process of regulating mash temperature by injecting heated water from the hot liquor tank into the mash tun at specific times.

 

When conducting a step infusion mash, differing temperatures and quantities of water are infused in the mash tun from the hot liquor tank at specific intervals or steps in the mash process to control sugar conversion and extraction.

 

When conducting a single infusion mash, the room temperature of the grains is compared with the desired mashing temperature and mash water volume. The hot liquor tank is then preheated to the appropriate temperature and the mash water is infused with the grains all at one time. The mash is maintained at a constant temperature until the mash out or sparging sequence begins.

 

RIMS or the recirculating infusion mash system is a mash infusion system that either utilizes a pump to recirculate the fluid in the mash over a secondary heat source (outside of the mash tun) to maintain the mash temperature, or constantly recirculates the mash onto itself while direct heat is applied to the mash tun to regulate temperature. The fluid is pumped at a rapid enough pace to keep the temperature of the mash at an equilibrium and prevents the wort from being scorched or overheated.

Hopback

July 11, 2013 / / 0 Comments

A hopback or hop back is a small hop-filled vessel, typically made of copper or stainless steel, that is placed between the brew kettle and wort chiller, or brew kettle and fermentation chamber. It is highly recommended that you place the hopback between the brew kettle and chiller if an external chiller is being used.

If the beer is chilled, then the wort flowing over the hops will be far less effective at extracting the resins and oils from the hops. If the temperature of the wort is under 170° F, the alpha acids will not isomerize, and no bitterness will be imparted on the wort. The aromas extracted from the hops will be diminished as well.

Whole hops are typically recommended or required for using most hopbacks, as pellet hops are more prone to clogging, and a good deal of the particulates from pellet hops will end up in your fermentation vessel. In addition to adding hop flavor and aroma to your wort, a hopback is also a valuable tool to filter the hot break and or cold break from your brew kettle to your fermenter. As the wort passes through the hopback, the hops will work as an organic screen, capturing many of the larger protein and particulate masses that enter it.

 

Below is the Blichmann Hop Rocket that I use when a hopback is needed for one of my beers.

Home Brewing Hopback / Hop Back, Blichmann Hop Rocket

Home brewing hopback/hop back, Blichmann hop rocket

Head Retention

July 10, 2013 / / 0 Comments

Head retention refers to a beer’s ability to retain its foamy head once the beer has been poured. In most styles of beer, a thick foamy head that does not dissipate too quickly is very desirable. The three primary factors that impact a beer’s head are the carbonation level of the beer, residual proteins that form the body of the finished beer, and isomerized humulones pulled from the hops that were added during a beer’s boil. Hops that are added during fermentation or once the beer has cooled below approximately 175° F will not isomerize and will have very little impact on head retention. A stronger or hoppier beer will tend to have better head retention because it will usually have more residual proteins and a greater amount of isomerized humulones.

 

The most common ways of enhancing a beer’s head retention are to add high alpha acid hops during the boil, utilize grains such as crystal malts or wheat, or add an adjunct such as maltodextrin to your boil. Striking the right balance is a bit of an art, as you do not want to compromise the taste of your beer or risk clarity issues by pushing too hard for good head retention.

 

Growler

July 9, 2013 / / 0 Comments

Growlers are large capacity beer containers that are typically made of glass, ceramic, or stainless steel. In the late 1990s, growlers began gaining in popularity at craft breweries and brewpubs as an easy way for patrons to take beer home when traditional bottling was not a reasonable option. A typical growler holds 64 or 68 fluid ounces, but they come in a variety of sizes. The top of the growler creates an airtight seal using either a screw cap or a hinge/latch style cap and can keep beer fresh for over a week if maintained properly.

Below is an example of five different styles of beer growlers: a ceramic Widmer Gasthaus growler, a Deschutes latch top glass growler, a small screw top glass growler, a Russian River latch top circular growler, and a Firestone large screw top growler.

An example of 5 different beer growlers

An example of five different beer growlers.

Grain Bill

July 9, 2013 / / 0 Comments

A grain bill or mash bill is the whole of the different malts, grains, and adjuncts that make up a beer. The grain bill is very important when designing a beer recipe, as it is primarily responsible for the potential original gravity, color, and diastatic power of the beer.

Flocculation

July 8, 2013 / / 0 Comments

Flocculation refers to a yeast strain’s tendency to clump together and drop out or fall out of suspension to the bottom of the fermenter or holding vessel. As yeast flocculates, the beer begins to clarify. Some yeast strains tend to have high flocculation, such as Wyeast Scottish – 1728, while other strains like Wyeast American Wheat – 1010 have very low flocculation. The physical appearance of the yeast cell plays a big part in its flocculation level.

It is important to choose a yeast with an appropriate flocculation profile when designing a beer; for instance you would not pair a Belgian Wit wort with a high flocculation yeast, as you want some of the yeast to stay in suspension in the finished beer.

Final Gravity

July 8, 2013 / / 0 Comments

The final gravity or FG of a beer is the beer’s specific gravity once fermentation has completed. Once a brewer has measured the final gravity, it can be compared to the original gravity and the ABV or alcohol by volume can be calculated. The final gravity of a beer is typically taken using a hydrometer or refractometer. Specialty final gravity hydrometers are available to allow you to take a more accurate reading of your final gravity if desired.

 

Below are three different types of hydrometers used for taking the specific gravity readings of beer.

Beer brewing hydrometers for taking specific gravity readings such as Original Gravity and Final Gravity

Beer brewing hydrometers for taking specific gravity readings such as original gravity and final gravity.

 

 

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