All-Grain Homebrewing Instructions: The Mash
If you are interested in brewing from grains, then the most important part of the process is the mash. If you screw this up, your beer will suck. If you get it right, then you have ultimate control over your beer�s flavor and character. Plus you have the self-satisfaction of knowing that you brewed your beer right from the grain.
Oh, and brewing from grain is cheaper than extract brewing (after you buy the equipment, of course).
Carbohydrates to Simple Sugars
If you understand the basics of beer brewing, then you know that beer yeast metabolizes sugars into Carbon Dioxide and Ethyl Alcohol. This process is called fermentation.
Here�s the problem, beer yeast cannot metabolize complex carbohydrates and starches, and barley is made up mostly of starch and carbohydrate (very little simple sugars).
Fortunately Nature has provided us with a convenient solution to this dilemma. Although the barley is mostly carbohydrate, barley also contains special enzymes that, given the right conditions, can break the carbohydrate chains down to maltose and glucose � the sugars your yeast like to eat. Other grains such as wheat, corn, and rye don�t have these enzymes, which is why beer is almost always made from barley.
As a beginning grain brewer, we are going to assume that the only grain you are using in your beer is barley. If you are considering making beer using other types of grain such as corn or wheat, then you will be adding another layer of complexity (protein rests, additional boil sessions, and store-bought enzymes) to the process. It is recommended that you start off with pure barley beers, and then once you have mastered this method, you can graduate up to making multi-grain beers.
There are two types of enzymes we are concerned with for our simple mash: Alpha-amylase and Beta-amylase.
In order to understand what is happening here, you need to understand that Starches and Carbohydrates are essentially long strings of simple sugar molecules. They are too long and complex for our beer yeast to metabolize, so we need to make them smaller and simpler.
We use the Alpha-amylase enzymes in our barley to �chop� the Starches into Dextrins � sugars that are made up of four or more glucose molecules. They are simpler than starches, but still too complex for our yeast.
At the same time, we use the Beta-amylase enzymes to �nibble� the ends of the chains down to glucose and maltose (maltose is a sugar molecule that is made up of two glucose molecules).
So that�s the theory, anyway. Now let�s take a look at the practical application.
The first thing you are going to do is make some hot cereal. You are going to mix warm water and barley (around 1.5 quarts of water per pound of grain), and bring this mixture up to a temperature between 145 and 158 degrees Fahrenheit. The easiest way to do this is to heat the water to 165 degrees Fahrenheit before adding it to the grain. Once you stir this in, it will resemble the consistency of oatmeal, and it should be within your target temperature range.
Generally speaking, if your mash is on the lower end of the temperature range then you will have a drier, lighter-bodied beer. Alternatively, if your mash is on the upper end of the range, then your beer will tend to be sweeter and have a fuller body.
The relatively small size of your equipment means you will have a hard time controlling your mash temperature precisely � your mash simply won�t have the thermal mass to hold a steady temperature. The best thing to do is to aim for the middle of the range (152 degrees Fahrenheit). But keep in mind that it is best to have a mash that is too cool than one that is too warm. Once the temperature gets above 160 degrees, the enzymes will be denatured quickly and you can�t bring them back once they are gone.
Tip: As a back-up, you can buy both Alpha and Beta-amylase enzymes from your local homebrew shop, or get them online. This way, if you screw up and accidentally denature your mash, then you can always add in a few teaspoons of additional enzyme and finish the job off.
If you were brewing 5 gallons of beer, then a �typical� mash would consist of about 8 lbs of grain mashed with about 3 gallons of water at 152 degrees.
You will hold the temperature for about 1 hour, stirring slowly about every 5 to 10 minutes. Every time you give your mash a stir, you will notice that the temperature will seem to change. This is just because you are redistributing the heat through your mash tun. If you have the ability to add heat to your tun, then you may do so, but be careful. Usually by the time your thermometer registers that the temperature is perfect, the mash is already too hot. Your thermometer takes a few minutes to �catch up� to the realities in your mash tun. This is a lesson I have had to learn over and over.
You can�t see the transformation of the starches happening. The molecules are far too small for you to see even under the most powerful optical microscope. However, you will notice that the liquid in your mash will begin to clarify and the stuff that almost looked gelatinous will be much looser and liquefied. There will appear to be clouds of protein material floating in the newly clarified liquid, and the surface of the mash will start to look shiny. This is a really good indication that your mash is working.
A better test to do is to take a tablespoon-full of your mash liquid (make sure there aren�t any bits of grain in it), and add a drop of iodide to it in a test tube with a cap on it. Shake this mixture up quickly. If the iodide solution quickly turns the liquid black, then there is still a large concentration of carbohydrate. If the iodide solution doesn�t change color quickly then your conversion is working well.
After the mash has completed (about an hour or so � there is usually little point to going over 2 hours because your enzymes will give out by then), you will strain off the liquid to your boil kettle.
It will seem like a frustratingly small amount of liquid will come out of your grains on this �first run�.
Therefore, you �sparge� your grains with hot (170 degrees Fahrenheit) water. Sparging just means rinsing. Basically what you are doing here is washing all those sugars off the grains and into your brew kettle. Depending on how high you want your beer�s gravity to be, you will most likely use about 2 quarts of water per pound of grain.
The trick here is to evenly distribute your sparge water over your grains (stirring helps), so that you get consistent coverage. It will take a few minutes for the sparge water to filter through the grain bed, and come out the spigot.
The wort that comes out (a.k.a. the �runnings�) will start off as a strong flow, and then slow to a trickle over time. When I do it, I go ahead and start my burner as soon as I have a few inches of wort in my kettle. By the time it boils, almost all the liquid will have filtered out of the grain bed. This saves time because I am heating the liquid up as it is entering the boil kettle.
I also allow the sparge to slowly dribble into the kettle throughout the boil. I don�t think most people do this, but I find that it helps to replace some of the liquid that boils off. Plus, I don�t have to feel so bad about leaving so much sugary goodness in the mash tun.
So, to review quickly:
For a �typical beer�, you will start off with 8 lbs of grain, and add 3 gallons of 165-degree water to it for your mash. This will make a mash that is about 152 degrees for one hour; stirring occasionally. You will then run that into your brew kettle and sparge the grains with 4 gallons of water at 170 degrees. Your yield into the brew kettle should be close to 5 gallons.
After this, you will bring the brew to a boil, add your hops and boil as normal for an hour or so � making adjustments as necessary for your particular recipe.
Once the boil is complete, you should always take a gravity and/or brix reading. Keep in mind that if you are using a hydrometer to measure your gravity, then it will only be accurate once your wort has cooled to room temperature (well, technically 60 degrees, but you can always adjust your reading for 70 degrees).
The boil will cause a significant amount of water to evaporate leaving your wort too concentrated. Add water to compensate, then transfer it into your fermenter. Pitch your yeast and ferment as usual.
Coming up next week, we�ll go into more detail about Boiling All-grain batches.