A lot of the terminology has to be understood in context of the processes they describe, too, so an overview of the process of making beer might be in order.
The first step in making beer is
malting, which is where grain (usually barley, but sometime wheat or rye) is steeped in a small amount of water to let it begin to sprout, then heated or kilned to stop the growth of the plant. The result is called
malt, which is a sweet, crumbly form of the grain that contains a large amount of the enzymes needed to convert starches into sugars. The majority of the malt is kilned at a low temperature for a short time, producing a
base malt, which contains large amounts of the malt enzymes. Other malts are kilned at different temperatures, sometimes dry and sometimes wet, to produce the different kinds of
specialty malts which are used to give beer different flavors and colors.
Don't worry too much about the details of the malting; no more than handful of homebrewers do their own malting. Most malt is produced by large commercial malthouses, and even the big commercial brewers mostly rely on them for their malt (Coors being the main exception, and even then only for certain beers). However, it is useful to know the properties of the
different types of malt, as they have a primary role in the final beer.
The nest step is
milling which is where the malt is gently crushed to separate the hulls from the kernels, and to break the kernels open so that water can get into them. Milling is something of an art, as too coarse a crush won't open up the malt enough, while too fine a crush will destroy the hulls and leave the kernels a fine powder, which can lead to complications in the mashing step.
As implied by that last statement, then next step is
mashing, which is where the malt is soaked in a certain amount of water and heated to the temperatures at which the starch converting enzymes work best. There are a number of different enzymes which take part in this, each of which operates in a different temperature range, but the most important ones are the alpha-amylases, which break starch chains in the middle of the chain, and beta-amylases, which break sugars off of the ends of starch chains (The Palmer book uses an
amusing allegory to explain the action of the different enzymes). Mashing thus consists of raising the temperature to the temperature appropriate for one enzyme, then letting the mash (the porridge of water and malt) rest for a period of time to let the enzymes work.
How many different rests you use, and at what temperatures, and for how long, depend on the malt and on the style of beer being made. Most English beers are made with malts prepared in a way to make it easy to heat it to a single temperature with a single long
starch conversion rest (or
saccharification rest); this is called
single infusion mashing. German beers, and some American beers, need multiple rests at different temperatures to get the protein content correct and to adjust the acidity of the mash before the main starch conversion rest. Traditionally, this was done by taking part of the mash out of the mash vessel (called a
mash tun) and boiling it, then putting it back into the mash tun to heat the rest of the mash; this is called
decoction mashing, and while it can produce better results in some cases it is much harder to do, so most modern brewers either add boiling water to the mash tun instead (
step infusion), or else simply heat the mash tun itself (
direct-heat mashing). Which you would use depends on the kind of beer you are making, and the type of mash tun you are using.
Just as an aside, there are a few different kinds of mash tuns used by homebrewers. One method is to put the mash into a kettle, which can be heated directly; the other main method is to use a cooler or some other insulated vessel, which requires you to use either decoction or infusions. A third approach, called Beer In A Bag (BIAB) is to have the mash inside of a mesh bag, which is hung or dipped into a kettle, like the first approach. Each of these approaches has it's advantages and disadvantages, most of which relate to the next step in the process, called
lautering.
Lautering is the process of draining off the sugar-water solution (called the
wort) from the spent malt, and then washing the malt with additional water to extract any remaining sugars. This is done by using a kind of filter or colander called a
lauter tun; most homebrewers use a combination mash and lauter tun (MLT) rather than a separate lauter tun. This can be done by the simple expedient of using a BIAB (you simply lift the bag out of the wort and drain it), or by putting a false bottom, a manifold, or a braid at the bottom of the mash tun, and a spigot out of the tun to drain the wort through. However it is done, the idea is that you separate the grains from the wort. Usually (except with BIAB), you would start by draining a small amount of the wort out, then returning it the the top of the lauter tun; this step, call
vorlauf, helps to remove any floating grits that are in the wort. You then would drain the wort out, and add fresh warm water to the lauter tun, a process called
sparging. You can either drain all the first runnings out and then add the water (
batch sparging) or you can add the water as the wort is being drained (
continuous or
on-the-fly sparging). Fly sparging generally gets better extraction, but batch sparging is much easier.
A this point, you have the complete wort drained into your
brew kettle (BK). You now would begin boiling the wort, in part to boil off the water and concentrate the wort. The other reason you boil the wort is for
hop extraction. Hops are a bitter herb which are added to beer to give it a more complex flavor; unhopped beer would be cloyingly sweet, so the bitterness makes it more drinkable. Also, hops act as a preservative, inhibiting the growth of unwanted bacteria while encouraging the growth of the yeast. Finally, hops add to the aroma of the beer; different strains of hops have different flavor and aroma contributions. You generally add the hops in three additions - the bittering hops, at the beginning of the hour boil, the flavor hops, added about 15 minutes before the boil is complete, and the aroma hops, which are right before the end of the boil either at five minutes to the end, or just after the heat is turned off, known as
flameout).
Now, all of this is a lot of work, so to make things easier for beginning brewers, there are
malt extracts, which are concentrated wort which is pre-packaged at just before the point where it would be boiled. Extracts can be either liquid, which is a thick, dark brown syrup, or dry, which is a light brown powder. Different extracts have different colors and flavors, depending on how it was made. To use extract, you add the extract to boiling water and stir it in thoroughly until it is dissolved. You then would add your hops as per usual and the rest of the brewing goes more or less the same for either all-grain or extract.
Once the boil is done, you will need to cool the wort as quickly as possible to avoid it getting contaminated with bacteria or wild yeast. This can be done through the simple expedient of submerging the brew kettle into a bath of ice water, though it is rather slow. A faster method is to use one of several types of
wort chillers. The most common type, the immersion chiller, consists of a coil of copper tubing which is submerged into the brew kettle and has cold water run through it. Faster still are counter-flow chillers, which consist of two hoses one inside the other, where the outer hose has cold water running through it and the inner hose has the wort run through it in the opposite direction. Fastest of all are the plate chillers, which consist of a compact series of radiator plates which the wort is run through, interleaved with other radiators through which cold water is run (again, in the opposite direction). Chillers range from around $40 for an immersion chiller, to around $200 for a top-of-the-line plate chiller. Either way, after the wort is chilled, the wort needs to go into the fermenter, a bucket or carboy which can be sealed up using an
airlock that let's CO
2 out but doesn't let oxygen in.
At this point, you would want to take a sample of the wort, and use a
hydrometer to measure the specific gravity (density) of the wort. This tells you how effective the mash and boil were, and lets you estimate the amount of alcohol it might end up with.
Once the wort is chilled, you pitch the yeast into the wort. This can be either dry yeast, similar to ordinary baker's yeast in appearance, or liquid yeast, which comes either in a vial or in a 'smack pack', a foil bag with a smaller bag of yeast nutrient inside of it. To get the best results, you want to prepare a
yeast starter, a bottle of pre-made wort which the yeast is allowed to multiply in ahead of time. Different strains of yeast have different properties; the main categories are
ale yeast, which ferments best around 60-70 deg. F and often has a lot of complex flavors, and
lager yeast, which ferments best at 45-55 deg. F and produces a cleaner, crisper flavor.
Once you have pitched the yeast, you need to seal the beer in the fermenter, and let the beer ferment for several days at minimum. To determine of the primary fermentation is finished, you need to take hydrometer readings, and once the readings are the same for three days running, it is finished. You can either bottle the beer now, or move it to a
secondary fermenter (or
bright tank) for further aging. Once you are ready to bottle the beer, you need to
rack it into a bottling bucket, then add
priming sugar to give it carbonation, before racking the beer into the bottles. You would use the bottle capper to press the crown caps into place. You then need to let the beer condition for at least two weeks before it is ready to drink.
