The Way of All-Grain (Old School)
Mashing involves a lot of complicated physics, biology and chemistry. Fortunately, you need to know nothing, absolutely nothing, about any of it. It happens whether you have studied or not. But a few rules help the process go more easily and more completely.
First figure out your recipe. We can help you come up with a good one if you want us to. If you are converting an old extract recipe, typically, for a beginner, seven pounds of malt extract will equal ten pounds of two-row base malt. Specialty malts (like crystal) can be used pound for pound. Your total grain bill, for your five gallon batch, should be around ten or twelve pounds.
Once you have your recipe, add up the total pounds of grain. Multiply that number by 1.33. This gives you the quarts of water that you will use. For instance, say you have ten pounds of grain, total. Ten times 1.33 means you will need 13.33 quarts of water. If you divide this number by four, you will get gallons (there are four quarts in a gallon). In that same example, you would now have 3.33 gallons of water. This will be your mash water.
Barley malt is mostly starch. But there are living enzymes in the grain that will convert starch to sugar: this is the key to the existence of beer. These enzymes are activated (and deactivated) by certain temperatures. For starch to change into sugar, the grains (with these natural enzymes) need to soak in 145 to 159 degree F. water.
So what is the easiest way to make this happen? Physics. Temperature and volume and mass can all be inter-related to each other, and, luckily, someone has done it before and figured it all out. For the sake of simplicity, we will start with a single infusion mash - this means you will only need to hit one temperature: the temperature which allows sugar conversion. As you gain advanced brewing experience, you may want to start trying double infusion (where you do a protein rest to break down residual malt proteins) or - the ultimate - decoction mashing, where you pull grains and water out of the mash pot and boil them seperately before adding them back in. Confused yet? Don't be. That is all down the line. Back to our first mash.
I am assuming that you are mashing in a ten-gallon cylindrical cooler, similar to the ones we sell at the store. The following procedures are also usable if you are mashing in a stainless steel stockpot, but may need some adaption. Fear not: it is hard to mess up a mash no matter how you do it.
So, we want our grains to soak in, let's say, 152 degree F water. This is a middle-of-the-road mash temperature (145 to 159 degrees are the end parameters). So, how do we get them there? Take the volume of mash water that you figured out from above and heat it about 12 to 14 degrees HIGHER than the target mash temperature. So in the above example, take the 3.33 gallons of water and heat it in your mash-tun to 164 - 166 degrees (Target 152 degrees plus 12 or 14). When you are heating the mash water, remove the pot from the heat source about two to three degrees short of your target temperature. So, in this example, you are heating up 3.33 gallons of water to 165 degrees. Take the pot off the burner when it gets to 163, and in the next minute you will see the temperature "float" up to 165. Works every time.
Pour the hot water into the ten-gallon cooler. Now, dump the ten pounds of cracked grains INTO the hot water (do NOT put the grain into the cooler first!) and stir thoroughly for five minutes. Do not check the temperature before the five minutes is up - it will not have stabilized and you may panic and mistakenly add ice or boiling water and really screw up the balance. Trust in Physics, my children. After five minutes, the temperature of the "porridge" should be just about 152 - 153 degrees. At this point you should lid the cooler mash-tun, or - if you are in a stockpot - insulate it with blankets, styrofoam, or whatever you can and let sit for sixty minutes.
If you are mashing in a stockpot, after thirty minutes, you may want to check the mash temperature and see if you have dropped below 145 degrees F. If you have, you can put the pot/mash-tun back on the stove and heat it GENTLY (while stirring continuously) back up to 152. Cover, re-insulate and leave until the sixty minutes is completely over...
If you are in a Gott cooler, the temperature should remain fine. You should not lose more than a few degrees over the course of the hour-long mash.
After the sixty minutes is up, open your mashtun and taste the grains and liquid. Everything should be sweet and syrupy. You have converted starch to sugar! Woohoo! Have a beer to celebrate. Now you need to rinse the sugary liquid out of the mashtun into your boilpot. There are many ways to do this, but we have begun to preach the simple "batch-sparging" method. This is the "newer" way that people have been mashing (I think I first heard about it ten or twelve years ago), and many people have told me that it gives them better extraction rates (which means more sugar per pound of grain used) than sparging with a sprinkler. It is also simpler, and involves less equipment, less expense and less hassle. If you want to try the alternative "sprinkler-sparging" method, you can always feel free to come by and I will explain it to you.
Backtracking for a second: as you are getting close to the end of your sixty minute mash, fill a stockpot with five gallons of water. (If you do not have a large enough pot, you can do this following step in two batches. Two-and-a-half gallons at a time.) Heat the water up to 170 to 180 degrees F. and hold it at that temperature as best you can.
No go back to your cooler/mashtun. Put it up on a table or bench. Be sure that there is a three to four foot length of plastic siphon tubing connected to your spigot, dangling down to the floor, with a hose clamp on it to restrict the flow rate. From your kitchen, find two stainless steel (or inert) saucepans, and bring them to your cooler. Open the spigot FULLY and allow the mash liquid to drain down into one of the saucepans. Use the hose clamp to slow down the flow rate so that the sweet liquid flows down at a moderate trickle. The slower you drain out (up to a point!), the better your extraction will be. Slow and steady is the way to go. You should notice that the liquid coming out is full of husks, debris and particulate matter. When the saucpan is 3/4 full, slip the OTHER (empty) saucepan into its position, and gently pour the collected mash liquid (from the first saucepan) back on top of the grain bed. Repeat with the second saucepan, rotating them back and forth until the liquid runs relatively clear. This is called "vorlaufing" and is basically a recirculation process used to clarify the wort.
Once your runoff is draining without chunks in it, slip your boilpot under the siphon tubing and begin to fill your boilpot. Dump any remaining liquid from the saucepans into the cooler, seal it up tight and allow the mash liquid to drain out of the cooler until the flow stops. This should take ten to fifteen minutes if restricted properly.
Shut off your spigot (or clamp your hose clamp on extra tight to prevent leakage) and open your cooler. Add 2.5 gallons of the water you heated up earlier. Be sure to is between 170 and 180 degrees F. Mix well with a long spoon or paddle, and then vorlauf again until clear. Once the sediment goes away and the wort clarifies, drain this 2.5 gallons of water into your brewpot. The draining should take another ten or fifteen minutes.
Repeat with the next 2.5 gallons.
You have now collected between seven and eight gallons of sweet liquid (wort) into your brewpot. Lift the pot up onto your propane burner and bring to a boil. Watch for foam-overs as it comes back to a boil! Once you have reached a full rolling boil, set a timer for thirty minutes, You want to boil your wort as hard as you can for thirty minutes in order to evaporate off some of the liquid and begin to concentrate the sugars. DO NOT BOIL WITH THE LID ON. Leave the lid off during your entire boil, start ot finish.
At the end of the thirty minute boil, add your first hop addition and re-set your timer for a sixty minute boil. From there (hopefully) you will have a recipe, telling you when to add in your remaining hops. From that point on, you will boil for sixty minutes, adding hops as needed for your recipe. Total boil time will be ninety minutes long.
At the end of the ninety minute (total) boil, turn off the heat, put a lid on the pot and chill your beer according to the type of wort chiller you have. Once the beer is down to 80 degrees or less, and is drained (or poured) into your primary fermenter, add your yeast. Be sure to check the volume of the beer at this point. If you have less than five gallons, top off with fresh water up to your five-gallon mark. If you have more than five gallons, make a note of this, and - on your next batch - be sure to "pre-boil" your wort for forty-five minutes (or as long as necessary) - instead of thirty minutes - before adding your first hop addition. Evaporation rates differ depending on your system, and this is a variable that you will want to adapt to your personal set-up.
As you are adding you yeast, take a hydrometer reading. If you know your total grain bill, the volume of beer in your fermenter and your specific gravity you can figure out your extraction rate. This is the amount of sugar each pound of grain is adding into your wort. This is importnat because it allows you to customize your recipes so that you hit the proper specific gravity that a recipe may call for.
For instance, twelve pounds of grain can produce a beer that ranges from 1.048 gravity to 1.076 gravity. This is a huge swing, and it all depends upon the brewer's system and skill level. It is analagous to hitting homeruns in baseball. Some hitters have a higher cahce than others. If you want to produce an IPA with a 1.060 gravity, you may need 9.5 or 15 total pounds of grain. If you want us at Main Street to help you with your recipes, we really need to know your extraction rate so that we can customize the recipes to your system.
Be sure to record total weight of grain, volume of beer in fermenter and starting gravity.
That's it! Let me know if you have any questions about this magical process...