All-Grain Brew Terminology

Preface

I am very new to this hobby so all grain brewing is a bit daunting for me.  I've written this mostly for myself as an excercise to familiarize myself with the terminology, but also to have it all in one place for reference.  Below is a list of commonly used terms with respect to all-grain brewing which will likely be foreign to a new brewer, or a brewer who has primarily worked with extract or pre-bundled extract kits.

Disclaimer: I did not write most of the content below, but rather pulled it together from several sources.  If any of the original authors has an issue with this, I will be happy to more specifically credit your work.  Sources are noted at the bottom of the article.

Equipment Terms

Hot Liquor Tank (HLT) - This is a "tank" used to heat your strike and sparge water.  In a 3-tier gravity setup, the HLT will typically be at the top of the brew structure.  Strike and sparge water is heated to appropriate temperatures, and gravity fed (or pumped) to the MLT.  You will often see this as a large 10G cooler with extra fittings on it, or a keggle.


10G Rubbermaid cooler, converted into a HLT

 Keggle - A standard half-keg, like one you would pick up at a beer distributor, which has been converted into brewing equipment.  The keggle can be used as any vessle for the brew process, custom fit to meet your needs

Mash Tun / Lauter Tun / Mash Lauter Tun (MLT)

• Mash Tun - A vessel in which grains will steep during the mash
• Lauter Tun - A vessel in which sugars are rinsed from the grain
• Mash Lauter Tun - A vessel which is used for both processes.  This is the typical setup you will see, and will commonly be abbreviated as MLT

Manifold / False Bottom - This is a raised section of fine grating that sits at the bottom of the MLT which prevents grain from getting into the boil.

Process Related Terms

Grain Bill - The grain ingredients used for the brew.  This will generally be 70-80% of a base malt, plus specialty grains for added color and flavor.

Strike / Strike Temperature - The temperature at which the mash will be performed.  The water used for the mash will be heated in the HLT (typically) to 15-20 degrees higher than the strike temperature.  The reason for this is when you add the grain, the temperature will lower

Mash - This is the process of soaking the grain bill for a period of time (at least 60m) to allow the enzymes to convert starch into sugar.  The mash will typically happen anywhere from 140-155 degrees F.

• At the lower range, 140-148, you will get a dryer beer
• Higher temperatures between 149-156 will yield a sweeter beer
• The amount of water used is based on a ratio of Water:Grain, typically between 1-2qts/lb
• For example, a 10lb grain bill with a 1.5:1 ratio would mean you will use 15qts water for your mash
• Thin mashes (higher water:grain ratio) may increase efficiency for low-gravity brews, but it may decrease efficiency in high-gravity brews because there would be so little sparge water

Mash In / Dough In - Mixing ground malt with water, the first step in all-grain brewing

Infusion Mash - Most common type of mash.  This is a technique in which a controlled amount of hot water is added to the grain to acheive the desired mash temperature

Decoction Mash - A traditional German method of mashing, in which mutliple temperature rests are employed.  The boost from one rest temperature to the next is achieved by removing a portion of the mash, boiling it in a separate vessel, then returning it to the main part of the mash

Mash Out - The final stage of mashing, where the temperature of the mash is raised to approximately 165ºF-170ºF for about 10m.  This stops enzyme activity, and also facilitates an easier and more efficient runoff, since sugars are more soluble at higher temperatures.  A mash-out is optional.

Lautering - The process of separating the sweet wort from the grains.  Some type of filter medium must be used between the grist and the lauter tun's drain valve to keep husk and other large particulates from entering the boil kettle.  Usually involves sparging.

Vorlauf - The process of clarifying the wort being drawn out of the mash tun.  Often this is as simple as drawing 1-2L of wort at a time slowly into a container and then pouring softly back onto the top of the mash; taking care to disturb the grain bed as little as possible. When the wort runs mostly clear (meaning no large pieces of grain material) the vorlauf process is complete and sparging may begin.

Sparge - Rinsing the grains after the mash

• Batch Sparge - Sparge is done in large steps.  A large voume of sparge water is added to the mash tun, stirred and drained.  This process is then repeated until the sparge is complete.
• Fly Sparge - Also sometimes called continuous sparging.  Water is added to the mash tun at the same rate as runoff, done in such a way as to not disturb the grain bed.  This will generally take about an hour.
• Stuck Sparge - This happens when the flow of the sparge is stopped when the false bottom of the mash tun becomes blocked or clogged
• Channeling - This will happen if the downward force of sparge water "drills" through the grain bed.  Imagine a tub filled with sand; if you take a bucket of water and dump it very quickly, the water will drill through the sand and fill in from the bottom.  This is exactly what you do not want to do with your sparge.  If the water is poured slowly, or spread out over the grain bed in a controlled manner over a long period of time, the whole grain bed will be properly rinsed.

Advanced Systems

RIMS - Recirculating Infusion Mash System - A mashing system in which a pump is used to continuously recirculate the liquid part of the mash through the mash bed.  Mash temperature is maintained by passing the liquid over a heating element; the heating element is cycled off and on to maintain the desired mash temperature.

HERMS - Heat Exchange Recirculating Mash System - A mashing system whereby mash temperature is controlled by circulating the liquid part of the mash through a heat exchanger.  The main difference between a HERMS and a RIMS system is that in a HERMS system, the wort never comes into direct contact with the heating element.

Mash / Brewhouse Efficiency

Mash Efficiency - Extraction efficiency is the ratio of the amount of sugars you actually obtain, to the theoretical maximum amount of sugars available.  In other words, 100% efficiency will extract 100% of the fermentable sugars from the grain

Mash or brewhouse efficiency is determined using the "gravity points" of the grain bed for a given recipe.  Some grains have more fermentable sugars than others.

For example, US Pale 2-Row has 37 gravity points per pound malt.  This means with 100% efficiency, using 8 pounds of US Pale 2-Row, you would get 296 points.  Divide this by the volume of wort collected to determine the max yield.  Let's say we got 5 gallons of wort, so 100% mash efficiency in this case would yield 59.2 points.  In other words, 1.059 SG.

If you measure your specific gravity and get a reading of 1.042 it means you have 42 ppg
Now to determine the mash efficiency, simply divide your reading by the maximum possible: 42/56 = .711
Multiply that by 100 to get a % will give you your mash efficiency: 71%

In the real world, a recipe will normally have more than 1 type of grain but the process remains the same.  Look at this recipe, taken from HBT:

http://www.homebrewtalk.com/f126/atonement-brown-porter-2011-hbt-gold-category-12-a-238714/

Atonement Brown Porter
UK Maris Otter 7.5lbs (38 ppg)
UK Brown Malt 2.5lbs (32 ppg)
US Black Malt .6lbs (26 ppg)
Boil Size: 6.5G

100% efficiency would yield:
(7.5 * 38) + (2.5 * 32) + (.6 * 26) = 380.6 ppg

Assuming all goes well, and we collect 6.5G of wort, 100% efficiency would yield ~59 ppg, or a SG reading of 1.059

If we take a SG reading after the wort is collected and get a reading of 1.048 (48 ppg), it means our mash efficiency here is 81.3% (41/59)

Brewhouse Efficiency - This is essentially the same as mash efficiency, but the SG and wort volume measurements are taken after the boil instead of before.  In other words, this will tell you the efficiency of your entire brew process, taking into account boil volumes, how much water you lost to evaporation during the boil etc...

Sources:
http://hbd.org/uchima/glossary/glossary.html
http://byo.com/resources/glossary
http://www.homebrewtalk.com/wiki/index.php/All-grain_brewing