(Rudely stolen from http://www.kuro5hin.org/story/2003/7/1/31030/24474)

Many people like to have some sort of pet, perhaps a dog or a cat. Some people, like me, like to keep their critters in little jars in a cabinet or the fridge. No, I'm not talking about bonsai kittens. I'm talking about yeast. These little critters can make everything you'll ever need, from bread to beer. Or maybe that's all it can make. In any case, we've seen how to make a fine sourdough bread already. My aim is to show you how to make your very own cold ones. Or, if you prefer, room temp-a-ture ones.

--------------------------------------------------------------------------------

The Theory

The idea behind brewing your own beer is simple, really. You need to take some barley and ferment it. Of course, it's never really that simple. See, fermentation is caused by the little critters we call yeast. They eat up the sugars present in your wort (unfermented beer, pronounced wert) and release alcohol. The problem is that barley isn't something that's digestible by the yeasts. There are too many starches that need to be broken down into simpler sugars.

The way this is done is through malting. Barley is sprayed with water in a controlled environment until it barely sprouts. The sprouting barley is then dried out, resulting in malted barley. The sprouts can't survive on the starches inside the grain either, so they start to break them down, giving you a suitable base for your brewski. Coincidentally, if you grind malt really fine, you get the same stuff used in malted milk balls or milk shakes.

Now that you have malted barley, all you need to do is feed it to some yeast, right? Wrong. Well, you could, but you wouldn't get a very good beer. What's missing? A crucial ingredient called hops. The hop plant is a relative of cannabis, and provides essential aromatic oils and bittering agents to the brew.

Okay great. Now we have everything. How about brewing the stuff? So we boil our malt and our cannabis, I mean, hops, then we put it in a vessel and bam. Not quite. You need to toss in a yeast. Yeast is the magic that makes it happen. And it's not enough to use that standard Fleischermeister stuff you find in the baking aisle. You need a brewing yeast. And you've got some choices. You can have an ale yeast or a lager yeast. Ale yeast is a top-brewing yeast, meaning it lives and floats on top of the wort as it ferments. It also works at slightly warmer temperatures. Lager on the other hand, well, I think you've figured it out. Bottom-living and cold-loving. It also does its job much slower than an ale yeast. Since I don't have the space in my fridge to store some 5 gallons of wort for several weeks, I like to use an ale yeast. The difference in taste is something that I can't really describe, since I've never brewed anything with a lager yeast, but if it helps, most American beers are actually pale German lagers. (The German isn't pale, but the lager is.)

Once this is done, you have a number of options. You can put it in a secondary fermentation, like bottling, or the other secondary fermentation (bright beer tank), and then bottle. Either way, when it goes into the bottles, you add a li'l bit of sugar to get some fermentation going, just a little bit, to get some carbon dioxide into the mix. Then, you let it sit a while, pop it into the fridge, and enjoy your fine drink in a nice frosty glass.

Sounds easy, doesn't it? Well, it is. First, let's start with your materials, shall we?

The hardware

One or two fermentation vessels
A big stock pot that can hold (potentially) 3 to 5 gallons of liquid
A long plastic or metal spoon
A funnel
A strainer that can sit comfortably in the mouth of your fermentation tub
A hydrometer
A probe thermometer
A Fermometer
An airlock
Bottles

And the software...

Water
Malt Extract
Milled, malted barley
Sugar
Hops
Yeast
Bleach
And now for something completely different... an explanation.

So I know you're looking at those lists and wondering, "Huh?" Well fear not! For all will be made clear. First of all, yes, the list of hardware is daunting, but it's not nearly as special as you think. Let's start with the fermentation vessel.

Your fermenter should have three things. It should have a solid, airtight seal on the lid. There should be some way for CO2 to escape. Lastly, it should have a way to extract the beer afterwards. Sounds complicated? How about a 7 gallon bucket? Sure, you may need to drill a hole in the lid for the airlock, and it doesn't have the spigot on the bottom that professional beer brewers have, but it costs next to nothing, and is perfectly okay for your first brew. And naturally, smaller brew, smaller bucket. You want your wort to mostly fill the bucket, but not too much. See, oxygen is bad because it... well... oxidizes things. Also, the air you're breathing can be hiding some pretty nasty stuff. So if we minimize exposure to oxygen, we'll be good. The less space between the liquid and the lid, the better. All the oxygen will be pushed out of the airlock by the CO2 generated during the brewing process.

Speaking of the airlock, you'll want to buy a commercial 3 piece glass airlock. Some people will tell you that a rubber balloon or plastic wrap and rubber bands are okay, but they're really unacceptable. Balloons are pourous, and may let nasty stuff into your precious brew. Don't worry. These things cost a dollar apiece, and will probably last longer than a bag of balloons for the same price. You'll want to cut a hole into the lid of your bucket (assuming you didn't get one of the expensive brewing buckets) and stuff a rubber bung fitted with an airlock into it. Your airlock will have a little line on the side. Fill it up to this line with water. The clever little mechanism will allow CO2 from the fermentation to escape, and prevent oxygen from getting in.

The rest of the hardware is mostly optional. You don't really need a thermometer, if you know what you're doing. The Fermometer is just a sticker-style thermometer that you attach to your fermentation vessel to keep it at a controlled temperature. (But how many of you have such fine control over your indoor heating to keep anything at a constant temperature?) The funnel and the strainer are useful items, but you may find that you don't need them. The hydrometer too, is super-useful, but we won't use it. However, it's incredibly important when making wine, but that's another story.

Oh yeah. You'll want an auto-siphon and some tubing so that you can.. uhh.. siphon things.

You generally want all of your equipment to be made of food-grade plastic or stainless steel. Aluminum may impart some off-flavors to your beer. Weak plastics are... well... weak. They may not hold up to the heat or the handling or what have you. I guess that most acceptable containers are made of poly-ethylene, but I'm hardly an expert on that.

Oh yeah, you'll want to sanitize everything as well as you can. You don't want nasty stuff turning your beer into not-beer. Plenty of microbes and bacteria can get in, ruining the batch. So you have to be as clean as possible by soaking everything that isn't an ingredient in a solution of 4 tablespoons of bleach to 5 gallons of water. Fill your bucket with it, slosh it around, put all your tools in the bucket, including the bucket lid, and let it sit for 10 minutes. Then drain and rinse with hot water to get the bleach smell out.

Enough talk! Let's make beer!

I suppose that you've sat through quite enough theory and talk. Let's see how it's done. The following information is for a 2.5 gallon tub of beer.

Start by sterilizing everything. Clean? Good. Now, take your steel pot and start boiling 4 cups of good clean water. When it comes to a boil, add your malt extract. Somewhere close to 3.5 pounds of it. You can get away with as little as 1.2, but 3.5 will give it more flavor. Toss in a little bit of your bittering hops, say oh, I dunno. I'm guessing a quarter ounce. I don't really know, I'm not terribly familiar with hopping my beer. Let it boil for maybe 30 minutes. This step is to wake up the flavors of the malt and hops. You'll want to watch it. It could easily boil over. If it looks threatening, turn the heat down, or stir it up a little.

Now, for the second application of hops. This is purely for aroma. Remove the pot from heat, then drop in about a quarter ounce of your favorite smelling hops (cascade seems to be popular) and let it steep for 5 minutes with the cover on.

Now, everything gets transferred to your fermentation dealie. Put about 4 quarts of water into the sanitized tub, then strain the malty liquid (called a mash) through your strainer lined with a cheesecloth, right into your tub. Don't worry about catching everything. You're going to transfer it all again after a week anyway. Now, top it to 2.5 gallons with water. Stir like a madman, using a sanitized spoon of course. Sprinkle your yeast packet (they come in convenient packets. Then cover it with the lid, attach your airlock, and run away. Well, don't run away, but don't touch it anymore. Let it sit. Put it in a relatively warm place that maintains temperature well. Let it sit for a week. You can watch your airlock bubble up and down while waiting for it to ferment. Or you could do something else. It's up to you.

After a week, you'll have beer. Almost. You can taste it. It'll probably taste pretty good. At this point, you can bottle it and be done, but you could also send it to the bright beer tank, where it matures and clarifies a little more, which undoubtedly improves the flavor. To go the bright beer route, simply siphon off all your beer (Using an auto-siphon, preferrably. You don't want to contaminate your beer with mouth bacteria this close to the end.) into another tub, and let it sit another week. Either way, you're going to end up siphoning your beer into something else. You'll be left with a strange looking mush called trub (pronounced troob) at the bottom of your fermenter. This is the yeast and various other solids precipitated out of your beer. They're quite high in protein, if you like that sort of thing. Anyway, on to bottling!

To add bubbles, you have to add sugar. Ordinary table sugar. C&H. Mommy uses it to bake us cakes sort of sugar. Sugar = CO2 in the grand equation of beer. How much sugar you ask? Well, it's hard to say. Too little sugar, and you get no fizz. Too much sugar, and your bottles start exploding. Consulting my handy-dandy chart I have here, you'll probably want either 1 teaspoon, 1 and 1/4 teaspoons, 2 and 1/2 teaspoons, or 1 and 1/2 tablespoons. That would be for 16 oz, 20 oz, 1 liter, and 2 liter bottles respectively. What's that you say? A 2 liter bottle of beer is absurd? Hardly. It's easier to transport, and it's easier to find a bottle for it. Those plain old plastic PET bottles that are used for sodas are perfect. They're cheap, and they can withstand the pressure of the carbonation. Just clean them out (and sanitize, I can't stress this enough) and put the appropriate amount of sugar in. Then, siphon your beer, or bright beer as appropriate, into the bottle. Fill up to some reasonable amount (it's hard to say exactly, pick something that looks good, not too full, but not too empty), then cap it off. You did remember to sterilize your caps, didn't you? Let that sit in a temperature-stable area, and after a week, voila! You have beer!

Afterthoughts

If the thought of brewing in a paint bucket scares you, you can always go for a commercial brewing system. Most will run you about 50 USD. You can do much better. I highly reccommend the Mr. Beer brewing system. It's half the capacity of the more expensive systems, which is far more manageable in a small apartment. Also, it lets you control the brew process completely, unlike other systems. However, their single serving cans of malt extract are a little weak, so you'll have to use more than one or supplement it with malt from another source.

Like any other alcoholic beverage, beer improves with time. More time in the primary fermentation stage, bright beer stage, or in the bottle will do wonders for your beer. While you could easily have a brew ready in two weeks, sometimes it's worth it for the flavor to mellow out for a while. It's also beneficial to cold condition the beer after it's been bottled. Put it in your fridge and let it sit for a few weeks before drinking.

Always remember to sanitize. Sanitize, sanitize, sanitize. Poor sanitization is the usual culprit for a skunky brew. The bleach solution works well and is quite cheap, but might be hard to rinse off. If it annoys you, you can always purchase a sanitizing solution or powder from your local brewmaster. Don't have a local brewmaster? There's always the internet. Look around.

While you can brew your beer in a bucket just fine, you may want to invest in an official fermenting tub, which is usually just a bucket with a hole for an airlock and a spigot. However, if you happen to be the intrepid type who cut a whole in the lid for the airlock anyway, you're probably clever enough to cut out a hole for a spigot, which can be purchased at various places online. Either way, the spigot is incredibly useful because it means that you don't have to siphon stuff around, which can get annoying.

I hope that clarified the mystery of beer, and that you're soon on your way to brewing your own batch. It's amusing and rewarding. Don't be afraid to experiment. Try making different flavors, like fruit. You could also try making different beers, like a stout, or a porter. There are plenty of recipes online. Most of all, have fun. What's the point of doing it if you don't enjoy it? Unless you're under 21 and this is the only way you can get alcohol, but you shouldn't be doing that anyway.