Like most brewers, I got into all-grain brewing way before I was intellectually and emotionally ready. I knew I needed hot water but I didn't understand, or probably care, about the need for precise mash temps, how starch is converted to sugar or sparging.
So I bought a 55 lb sack of 2-row and cracked it by running it through an old meat grinder. Then I tied it up in a sack and put it in an old church coffee pot. I thought if it sat there while the water was heating it would go through all of the protein rests.
After a while, I didn't have any consistency to how long I would wait, I would pour the wort into my 4.5 gallon pot until it was more or less filled up and then add DME until I hit the target OG. God, just writing it down makes it sound even more asinine than it was in my head.
I was getting about 30 percent to 40 percent efficiency and beers with a little more depth than straight extract, but not very much, and no body. In general, a disaster.
All-grain brewing is the holy grail of homebrewers everywhere. And it should be. With all-grain you will be able to dial in a recipe perfectly, turn out awesome and complex beers, get crystal clarity and be able to truly say you crafted this beer from the ground up.
However, before you jump into all-grain you need to consistently make good beer using extract. To paraphrase Jamil Zainasheff, knowing and understanding fermentation is way more important than knowing how to convert starch to sugar. The hot side can be pretty forgiving but the cold side won't be. Otherwise, if your results are inconsistent with extract, you will never know what you are doing wrong when you go all-grain.
So your extract beers are good and you decide to make the plunge. To do so, you need to understand what is going on during the process, you need to get used to your equipment and understand how it works.
So what is going on.
A kernel of barley is contains starch, which is a long series of sugar molecules stuck together in a line. What you want to do is break the long chain of sugar molecules up so yeast can eat them. It is kind of like going to a movie and sharing a three foot long licorice rope with a friend but you have a cold and so neither one of you can just bite pieces off. The first step is taking the wrapper off, which is the grind of your grain. Then you need to break it down in to bite sized chunks though either pulling it apart or cutting it, which is essentially what is happening as different enzymes are activated during the mashing process. For a more intellectual explanation check out How to Brew by John Palmer.
This may sound complicated but, as a species, we have been making beer for several thousands of years before anyone understood what was going on at the molecular level so don't worry if the chemistry is beyond you. What we are doing is making barley soup, then straining the barley out to get the wort.
On the most basic level this is what you do. Heat around 5 gallons of water to about 170 degrees. Pour this into your grain, hitting a temp of around 153 degrees. Let this sit for an hour. Drain the wort and flush the grains, or sparge, with about another 4 or 5 gallons of hot water. Gather all the liquid and brew just like you used to with extract.
What you need to accomplish.
An all grain system needs to do several things and requires three vessels. One vessel needs to heat 5-7 gallons of water to your grain. Then you need a vessel to hold around 20 pounds of grain and the 5-7 gallons of water at around 150 degrees for an hour. I use a cooler with a false bottom I make out of Plexiglas and a drain spout. For the sparge water I use a church sized coffee pot, which has the advantage of being able to just plug it in and forget about it but the disadvantage of not being able to change sparge temps. The wort is all collected in my boil pot.
This is not a super complicated system and it has the advantages of working fairly well and being cheap. Like everyone else who all-grain brews I would love to have a computer controlled Blichmann system. However, those kind of systems cost over $3,000 and, if you don't know how to ferment a beer, they are not going to make a damn bit of difference, you will still be producing shit beer.
Of course, when adding another complicated procedure to your brew day there is a ton of ways to screw things up. Here are a few mistakes I have made and how to do it right.
Blowing the strike temp.
You will want to have control over the temperature your mash is sitting at for an hour. The first time I brewed all-grain I heated my water to 153 degrees, because that is what I wanted my grain bed to be. Then I put the hot water in a cooler filled with 15 pounds of grain, which was all at room temps. Had I a basic understanding of thermodynamics I would have realized this was dumb.
Predictably, my mash temp was only 140 degrees and I was running around in a wild panic trying to boil a gallon or two of water so I can raise the temps before I wrecked my beer.
So this is what you should do. Heat your strike water to around 170 degrees and have a gallon of cold water on hand. When you mash in take a thermometer reading and add a little cold water, slowly, until you hit your temp. Stir your mash up really well to make sure everything is wet and leave it alone for an hour. The malted grains you are buying right now are of very high quality so, for the most part, you won't have to worry about malt not converting. Just let it be.
Patience
Once I make sure my grain is good and wet and don't screw with it any more. I have found stirring it up, especially during the sparge, will get a lot of chaff and shit in my boil kettle. While it is true you can get more fermentables if you stir, I site Brewing Maxim #1, "Don't be a cheapass!" It is worth the extra pound or so of grain it will take to make up the difference in clear beer or chunky stuff.
If you want to hurry things along a little bit, set up your system so your boil kettle is on your burner, after you get a few gallons in there put a little heat to it. You probably don't want to bring it to a boil, just pretty close, then when the sparge is done you are just a few minutes away from having boiling wort.
Clearing
To further clear the beer, take the first gallon or two of the sparge, before you start running sparge water, and poor it back on your grain bed. I even let my water level get a little below the top of my bed. This allows the bed to set a little bit and act as a filter. What I am looking for is a stratification of the sparge water and wort, this will help push all the wort out of your mash instead of diluting it.
Once the grain bed is set and you start your spage water flowing into the mash tun start the output into the boil kettle. This will be pretty slow, at a rate of about one pint a minute and it can take around an hour to get sparged out. This is annoying but if you rush things you will either not get as much sugar as you want, or get tannins and chaff in your beer. Just relax and go have a beer.