All grain overviewWhen I first started brewing I thought all grain brewing was really complex and it would take months, if not years, to understand the complexity of turning solid grain into delicious wort. There is actually a lot of science you can learn but you don't have to know very much to produce drinkable beer. I would encourage you to learn more about the science behind brewing to grow beyond drinkable beer to great beer after you become comfortable with the basics.
At it's core, all grain brewing is very simple. You make a big pot of stewed grain, a lot like making oatmeal. You make it at a particular temperature and let it sit for a while. Then you dump the liquid--now wort--into your kettle. Pour in more hot liquid of a particular temperature and then dump that wort out into your kettle. Then you boil all that wort just like you would making extract beer. So the key skills to brew all grain are:
- Measuring volumes of water
- Reading and using a thermometer
- Using a heat source
Let me give you the bite-sized explanation of what we want to accomplish in this process. We want to take malted grains (or primarily malted grains) and add water at a temperature that will activate enzymes in the grain to convert the starches in the grain into sugar. When that conversion ends we want to take the water, sugar and flavor compounds away from the grain. When we do that some of the sugars and flavor compounds get left behind on the grain. So we add more water to rinse the extra sugars and flavor compounds off the grain and get them in our kettle. After that the grain is no longer part of the brewing process. We just need the wort we have created to make beer. Basically there is the conversion step and then we are trying to get the good stuff into the kettle and leave the grain behind.
Steps to all grain brewingTo expand on our simple explanation, all grain brewing is concerned with two main stages: the mash and the sparge. The mash is the mixing of water and grain through the conversion process and removing the first water addition, what are called first runnings. The mash can also refer to the physical combination of water and grains. "Mash" is both a verb and noun. The sparge is the later process of adding more water to rinse the grain and removing the latter additions of water, known as second runnings and even third runnings if you add water a third time.
Let's also start out with a bite-sized discussion of the equipment you need to brew. All grain requires at least two key pieces of equipment. The first piece is the mash tun. This is the vessel where you conduct your mash. It can be a large insulated vessel like a cooler or a large pot with a lid. It's goal is to provide a place for the conversion to occur. After the mash you will dump your sparge water into the mash tun since your grains are still in there with precious sugars and flavor compounds stuck to them. The second key piece of equipment is a vessel that you can heat water in. This is called a hot liquor tank but typically it is just going to be your kettle or another pot on your stove. Your hot liquor tank is where you will heat the water for your mash and sparge. (In larger breweries they need a separate tank to heat water independently of their kettle because the kettle may be in use boiling wort or holding wort from the mash while they also need hot water.) Technically if you use your boil kettle as a hot liquor tank you may need a third vessel to capture the wort from the mash while you have sparge water heating in your kettle. But that may be a system-dependent need we can address later. So now you should have an idea of the basic process plus the basic equipment used in the process. So let's get into the actual steps with some science mixed in.
Step 1: Preparing the grain
As you already know, the mash involves a conversion of starch into sugar. To maximize the value of our grain we want to break apart the grain so more of the starchy material can come in direct contact with the water and convert into sugar. To do this, we use a grain mill to break apart, or crush, the grains. You might wonder why we don't turn grain into flour, since that would make basically all the starch come in contact with the water. The reason why we don't do that is because there would be no way to get the wort back out of the mash. You would have a soupy bread dough. Instead, you want to keep some of the husk from the barley intact and the actual grain to stay in slightly larger pieces so the combination of husk and grain bits can form a porous bed of grain that will allow you to remove the wort or runnings from the mash and sparge. If the grain bed is not porous enough you will have a stuck mash or stuck sparge where you cannot get the runnings out of the mash tun. That is really bad.
There is a balance between crushing the grain finely to maximize starch exposure and crushing coarsely to get the runnings back out of the grain. Each brewing system requires a slightly different balance. The less you need the grain bed to be porous the more finely you can crush the grain and get more sugar out of the grain. The more sugar you can get out of the same volume of grain is known as mash efficiency. A high mash efficiency is great because you can use less grain to get the desired amount of sugar but if you are getting stuck mashes or stuck sparges where you can't get the runnings back out then your high mash efficiency is pretty useless.
Step 2: Doughing in
Once you have your grain crushed you can add them to the mash tun where they will await an infusion of mash water at a particular temperature. When you dough in, you add the water at a temperature slightly higher than what you want for the mash because the mash tun and grains are cooler than the mash water, so by the time the temperature equalizes you will be at your preferred mash temperature, which we will discuss in the next step.
There is no magic way to add the water, you just dump it in. Once the water is added, you need to thoroughly mix the mash to make sure the temperature is even and you do not have dough balls. Dough balls form when dry grains get surrounded by wet grains and form sort of a gel around the dry grains on the inside and keep the dry grains dry. If the grains aren't coming in contact with the water then there is no conversion. No conversion means wasted grains. The only way to destroy dough balls is to thoroughly mix the mash to break them up.
Step 3: The mash
The mash is an easy process for you. You are just going to let the mash sit and the grain will do all the hard work for you. A typical homebrew mash will last 45-75 minutes. The mash must occur at saccharification temperatures, which are between 145F-160F (actually a little above and below but most brewers stay within this range). At this temperature two important processes occur. First, this temperature the starches in malted barley and wheat will gelatinize, which makes conversion into sugar easier. This is kind of like when add hot water to oatmeal and the grains turn from firm, distinctly-shaped oat flakes into sort of a sticky, goopy mass. However, our mash won't get as much of a blob texture because we didn't crush the grain very fine and we have all the malted barley husks helping keep things broken up. However, like oatmeal, the gelatinized starches absorb the water where the second process occurs.
At these temperatures the malted grains can also release enzymes responsible for converting starch into sugar. These enzymes are water soluble, so the gelatinized starches will absorb the enzymes and the enzymes can go to work. There are two kinds of enzymes that are available at mash temperatures. In the 140s and mid 150s the grain releases beta-amylase which breaks starches down into maltose, the primary sugar in beer. Beers fermented at lower temperatures tend to ferment more thoroughly because beer yeast can completely ferment maltose. In the low 150s up into the mid 160s a second enzyme is released called alpha-amylase. Alpha-amylase creates maltose but it also leaves behind dextrins/maltodextrins, which are not fermentable by saccharomyces and helps create body in your beer.
Most beer styles do not benefit from very high temperatures where fermentability is low and body is full nor do they benefit from very low temperatures where fermentability is very high but there are no dextrins to leave some body. For that reason, most people ferment in the 150-154F range where both enzymes are activated and you can get plenty of maltose but also maintain a little body. However, some styles do benefit from mashing lower or higher. Budweiser, for example, mashes for two hours in the very low 140s so it will be highly fermentable and thin for volume consumption. It takes two hours because enzymes work slower at cooler temperatures and faster at warmer temperatures.
A key concern with the mash is that you have enough enzyme available to completely convert the available gelatinized starches. Grain considered "base malt" are those that contain enzymes that can be released during the mash. The enzymes are created in malted grains during the malting process. Grain is soaked in water at warm temperatures that makes the grain think it is hanging out in warm, moist spring soil. That causes it to start to grow. Maltsters will stop the growing process at a desired point by kilning the grain, which means they bake it in an oven to a temperature that stops the growing process and dries the grain out. They can kiln the grain to higher temperatures to create darker specialty malts. If they kiln the moist grain at saccharification temperatures they will create sugars within the grain and then heat the grain to a higher temperature to create crystal malts by caramelizing the sugars trapped in the grain. These higher temperatures used on specialty grains denature the enzymes, which why is you cannot ever make a 100% roasted barley beer. Unmalted grain also do not have enzymes because they have not undergone the malting process.
Since only some grain will have enzymes available it is important that your recipe has enough enzymatic power to convert the available starches. The enzymatic power of malted grain is known as diastatic power and is measured in Linter. Base grain and a few specialty malts are the only grains with diastatic power, which still has enzymatic power, include: two row and six row malted barley, malted wheat, pilsner malt, vienna, munich, aromatic, malted rye, malted oats, aromatic, amber malt, mild malt, maris otter and melanoidin malt.
Not all of these grains have enough diastatic power to convert their own starches, let alone the starches in other specialty grains. Base grain must be included in your recipe at a rate high enough to reach full conversion. Base grain include two row, six row, wheat malt, pilsner, vienna, munich and maris otter. Six row and wheat malt have the most diastatic power while munich has the least. The more diastatic power in the base malt, the less base malt you must use to reach full conversion on a recipe. A beer that uses munich as a base malt, especially darker munich varieties, must have a small amount of specialty grain to make sure there is enough diastatic power to reach full conversion. Otherwise you must add some other base grain to reach sufficient diastatic power in your mash. You can easily find more information about the Linter of each grain and how to calculate diastatic power all over the internet if you want to do the math. My rule of thumb is never to use less than 60% base malt and if only vienna or munich are used, use no less than 80%. It has yet to fail me.
Some people raise the temperature at the end of the mash to 165-168F. At this hotter temperature the enzymes will work very fast to complete any remaining conversion that may not have occurred during the mash. That is generally done to improve a sluggish mash where the enzymes are not doing their job very well or there might not have been enough enzymes to go around to reach full conversion at normal temperatures. Some people like to do it just as an insurance policy to make sure full conversion was reached.
Another technique some people use is a mash out. A mash out also occurs at the very end of the mash where the mash temperature is raised above 168F. At this temperature the enzymes in the mash are denatured and no further conversion can occur. The reason you might want to do this is to prevent the enzymes from continuing to break down the dextrins into maltose while you are performing the next two steps. If you are concerned about the beer becoming too fermentable or too thin you may want to mash out. The next two steps can take as much as two hours (longer as your brewing system increases in size), which is a lot of time for beta-amylase to find dextrins and other complex sugars and break them down to maltose.
Both of these latter steps are not absolutely necessary and I tend not to do either. You can make some decisions on whether you want to adopt those practices. Additionally, mashes need certain ph conditions and certain minerals for good mash efficiency and full conversion. Those are both far more advanced subjects than a basic primer should address, although you should put them on your list of future topics to research because they are very important to fine tuning your beer. For your introduction to all grain brewing you should use a decent quality water (either tap or store-bough drinking water) but avoid distilled or reverse osmosis water because they lack the necessary minerals.
Step 4: Vorlouf
Vorlouf is a fun word I probably mispronounce. A vorlouf is used in a traditional mash tun system (if you want to brew in a bag you do not have a need for this step). You slowly run off some of the first runnings from the mash to reduce the liquid content. The benefit of the vorlouf is that as the liquid volume declines the grain in the mash will start to compact together and form what is called a grain bed, basically just a stable mass of grain. This allows your runnings to pour through the grain bed and the grain bed will act like a filter to keep small bits of grain and proteins from the grain from getting into your kettle and eventually into your fermentor. By eliminating these extra proteins and grain bits you improve beer clarity, reduce trub in the fermentor and reduce the likelihood of boiling grain bits in your kettle. Boiling grain releases starches and tannins into the wort. You don't want starches floating around in your beer creating starch haze and adding a starchy flavor to your beer (unless you are making a beer like a witbeer that does want a little of that character). Once the runnings pour free of visible pieces of grain you are done with the vorlouf. You want to gently return the runnings to the mash so they will drain through the grain bed and come back out without those grain bits and proteins.
Step 5: First runnings
After the vorlouf you want to drain all your delicious wort from the mash to your kettle or wherever you need to store the first runnings until your kettle is free. As you drain the wort the grain bed will continue to compact. Naturally some of the sugars are going to get stuck to the grain and the walls of your mash tun as the wort is draining out. You need to get those out with your next step.
Step 6: The sparge
As I explained above, sparge is just a fancy word for rinse. In the sparge you are going to add water around 170F to the mash to get the leftover sugars and flavor compounds out of the grain. The reason you use hot water is hot water does a better job of rinsing the sugars off the grain in the same way hot water does a better job cleaning dishes or laundry. After draining your first runnings you have a lot of sugar and flavor compounds left behind you need to get into your kettle, so a hot water bath will get that done.
There are two ways to sparge, at least for homebrewers. One method is to fly sparge. This involves gently pouring a constant stream of water into the grain bed to flood the grains but allow the grain bed to stay intact so when you are draining off the sparge water that is now your second runnings of wort, the grain bed can continue to filter out grain bits and proteins. The other method is batch sparging. Batch sparging involves dumping a big volume of water into the mash tun and stirring it up to liberate the sugars. You then let the grains resettle to form a new grain bed and you can run off your second runnings. Depending on your sparge water volume and personal preferences, you may choose to do one batch of water or two batches of water. Both fly and batch sparging are perfectly acceptable and produce comparable results. Batch sparging is more common with newer brewers because it requires no special equipment. Fly sparging requires a device to produce that gentle stream of water over the grain bed. It is like an upside down water sprinkler that you rest on the top of the mash tun.
Step 7: Combine all runnings
This is sort of ovbious, but once you have run off all the runnings you need you combine all the runnings in your kettle and get to work trying to reach a boil. The combination of runnings produces your boil volume, so it is important that your recipe specifies how much mash water and how much sparge water you need to use so the combination of runnings will give you the correct boil volume. After that, all you need to do is discard your spent grain and clean up. That's it. Like I said at the beginning, you are really just taking turns heating water, adding water and draining water.
More information?As you are ready to learn more about the science behind all grain brewing, there are many good resources to turn to. Gordon Strong's Master Lessons for Advanced Homebrewers is actually a fine book to pick up as you transition into all grain brewing, in spite of the name. Palmer's How to Brew is fine although some of the information is dated and somewhat suspect (especially the online version). If you really love the science you can get into more technical detail in Noonan's Brewing Lager Beer. Of course, plenty of blogs and forums have useful information.
When you are ready to get into more advanced stages of all grain brewing you will want to start looking at water ph and brewing salts. The best place to get started down this path is Bru'n Water, the best online tool for adjusting your water. A wealth of information precedes the tool.
In the second installment of this series I will talk about equipment at the homebrewing level and give you some options for set ups at the small batch level. There are lots of good resources about larger set ups out there if you are looking for an all grain set up for five gallon batches or larger.
Have questions? Disagree with what I've said? Feel free to post in the comments below. Be gentle with criticizing the lack of depth in explaining the science above. This is meant to be an introduction, not a technical manual.