A sparge arm is a piece of brewing hardware used to flush the grain bed with hot water in order to extract any residual sugars left behind in the mash. The sparge arm water needs to be in the range of 168° F in order to liquefy the remaining sugars; if the temperature exceeds 170° F, the brewer many risk pulling excess tannins from the grain husks and causing off flavors and chill haze in the finished beer. Sparge arms are typically constructed of copper, stainless steel, or plastic, and should have some form of flow control so that the approximate flow rate can be set to keep pace with the flow of wort leaving the mash tun (or lauter tun) and heading to the boil kettle.
Below are three examples of home brewing sparge arms. From left to right, there is a MoreBeer.com “Ultimate Sparge Arm,” a rigid copper sparge arm, and a fly sparge arm with a stainless bracket. I have used each one of these and am currently using the MoreBeer.com sparge arm due to its versatility, which allows me to integrate it into my RIMS system.
Wort is the name given to the sugar rich liquid that is extracted from the mash prior to fermentation. Prior to the boil, when the hops have not yet bittered the wort, it is known as sweet wort. After the boil but prior to fermentation, it is known as bitter wort since the beta acids from the hops have imparted a bitter flavor upon it.
A photo of sweet wort being transferred from the mash tun to the boil kettle after sparging had completed:
Wort (unfermented beer) being transferred after sparging.
Whirlpooling is the process of separating the trub from the wort by utilizing centrifugal force to confine the trub to the center of the kettle so the wort can be drawn off without disturbing the trub cone. Whirlpooling can be achieved by quickly moving the wort in a clockwise or counterclockwise motion until a vortex begins to form in the center of the kettle. Once the vortex has formed, the trub will begin collecting and settling into the center of the kettle, forming a cone as the spinning wort forces the denser particulates towards the center. It is important to allow 15 to 20 minutes for the cone to form before drawing the wort from the kettle. If you are using an immersion chiller, you would want to chill the wort prior to whirlpooling and then draw the wort out slowly as not to disturb to trub cone.
Photo of a 20 gallon boil kettle after the boil had completed and the wort had been whirlpooled and much of the wort had been drawn off.
Recirculation is the process of pulling the wort from the base of the mash tun or lauter tun and recirculating it back on to the top of the grain bed. Recirculation typically occurs after the end of the mashing process. As the hot wort is recirculated through the grain bed of the mash, the grains act as a particle filter clearing the wort. As the wort is recirculating, it becomes cleaner and less turbid until finally it is clear and ready to be passed to the boiling vessel.
A pump is typically used to recirculate the wort at a steady and controlled pace. In the case where a home brewer does not have a pump available, the wort may be drawn into a container and slowly poured back on top of the grain bed. The process can be repeated until the wort has become clear. Additionally, rice hulls may be added to a mash as a means of boosting the filtration capability of the grain bed.
A wide selection of home brewing recirculation pumps can be found here:
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.
The boil is the stage of the brewing process during which wort is boiled in the brew kettle and hops could be added. When hops are added to the boil, hop resin/alpha and beta acid isomerization occurs, which imparts bittering and hop aroma in the finished beer. A typically boil time lasts between 60 and 90 minutes. The longer the hops’ isomerization in the boiling wort, the greater the potential for bittering that exists. In addition to hop isomerization, the boil also sterilizes the wort, denaturing the enzymes that were active in the mash. The boil is also responsible for the hot break, which removes several unwanted compounds that can cause both unwanted flavors in chill haze.
Below is a photo of a boil kettle a few minutes after the boil was achieved.
The process of adding, mixing or injecting air or oxygen into the cooled wort immediately before or after the yeast has been pitched. When aerating your wort, it is critical to keep its temperature under 80 F in order to avoid hot side aeration which will oxidize the wort and potentially cause off flavors in your finished beer.
There are several different ways to aerate your wort. The typical methods include injection and agitation.
The image below is a carboy filled with wort that is being aerated.
Yeast Pitching and Aeration just prior to fermentation