Your First Infusion Mash
All-grain brewing equipment for 5-gallon (19 L) batches
- mash tun/lauter tun (necessary)
- 7-gallon (26 L) or larger kettle (necessary)
- mash paddle (recommended)
- propane burner (recommended)
- wort chiller (recommended)
- iodine solution (optional)
- pH meter/strips (recommended)
- grain mill (optional)
I approached my first all-grain brew as I approach everything in my life — as geekily as possible. I read every available homebrew book and magazine article I could find. I worried about every possible detail and sweated every option. I drew up a checklist of things to do and a schedule by which to do them. Then, finally, I tried it. If I could go back in time and give myself one piece of advice, it would be to try a cookbook version of all-grain brewing first, then learn about the details as needed.
In all-grain brewing, you make your wort (unfermented beer) from roughly 10 pounds (4.5 kg) of malted grains instead of two cans of malt extract — assuming you’re making five gallons (19 L) of roughly average-strength beer. The wort is extracted from the grain through a process called mashing.
Although entire books could be (and have been) written on the details of mashing, it is — at its core — very simple. Stripped of all the brewing jargon, mashing is just soaking malted grain in hot water and then draining the resulting liquid away from the grain husks. Although there is a wealth of technical information about mashing, you don’t need to know it all to try all-grain brewing. You can just jump in and let your problems — if you encounter any — be a guide to what you need to learn. Remember, the English were making bitter and the Germans were making bock long before any of these details were known by anybody.
The simplest mashing procedure is called a single infusion mash. In a single infusion mash, crushed grain is mixed with hot water and the mixture is allowed to stand awhile before the liquid is drained away from the grain bed. Although this is the easiest form of mashing, it doesn’t mean it’s inferior to other types of mashing. Many beer styles — including pale ale, porter and stout — are traditionally made from single infusion mashes and many base grains are malted specifically for use in single infusion mashes. Your favorite ale from your local brewpub is likely made from this type of mash. In this article I’ll explain how to do a single infusion mash. I’ll focus on the techniques and mostly skip the theory.
Advantages and Disadvantages
There are several advantages to brewing beer from grains. With all-grain brewing, you can make beer from any imaginable combination of malted base grains, specialty grains, unmalted grains and starchy adjuncts. Base grains include pale, Pilsner, Vienna and Munich malts. Specialty grains include chocolate malt, crystal malt and roasted barley. Corn and rice are common starchy adjuncts.
All-grain brewing also allows more control over the fermentability of your wort. This is especially important if you like your beers dry. Worts made from extract are almost always less fermentable than all-grain worts (or at least those designed to be highly fermentable). In addition, all-grain brewing allows for better control over beer color, especially when making light-colored beers. Finally, it’s cheaper (after the initial investment in new equipment). Ten pounds (4.5 kg) of malted grain to make a typical batch costs about five to six bucks, while two cans of extract might cost over $20.
The recipe at left illustrates some of the options you can explore and the control you can exert with all-grain brewing. The recipe makes a lightly-colored and flavored beer with a spicy hop kick. The recipe uses a small amount of adjunct (flaked maize) and lower mashing temperatures to decrease the body a bit and make a clean, dry beer. In terms of style, it’s similar to a Kölsch or a cream ale (although it couldn’t pass as either). I just call it a lawnmower beer and make a big batch of it every summer, which in Texas seems to start in February and last through November. (Of course, you can make big, dark, malty beers with all-grain brewing, too.)
One disadvantage of all-grain brewing is that you need some new equipment. See the equipment sidebar for a list of required and recommended equipment. With all-grain brewing, you will also have to spend more time on brew day. Mashing typically lasts for an hour and separating the wort (lautering) takes another 90 minutes. It also takes extra time to heat the water and crush the grain. Extract brewing is faster and easier, but either way, you wind up with great beer.
Crushing the Grain
Before you can begin mashing, you must crush your grain or get it crushed for you. Crushing the grain breaks the hull and exposes the interior of the grain kernel. This allows the mash water to dissolve the starch in the center of the kernel and the enzymes in the malt to float free in solution and degrade the starch into simpler sugars. A proper crush of your grain is one of the four most important variables in all-grain brewing.
Grain is crushed in a device called a grain mill. If properly crushed, the barley hull will break into two or three pieces and the starch inside will exist as a few “chunks.” Individual grains will not hang together. If the malt is not crushed adequately, the hulls may be cracked but the whole kernel hangs together. In overcrushed malt, the hull is fragmented into multiple pieces and some or all of the starchy interior is reduced to a fine powder.
Most homebrew shops have a grain mill and will crush your grain for you, sometimes for a small charge. Some malting companies also sell crushed grain. One benefit of buying crushed grain is that this variable has been taken care of for you. Crushed malt from a malting company is likely to have been properly crushed. Likewise, most homebrew shops do a good job of crushing. It’s best to use crushed grain as soon as possible after crushing, within three months or so, assuming it’s kept in a cool, dry place.
Many all-grain brewers crush their own malt. To do this, you need a grain mill. An advantage to crushing your own malt is that you can wait until brew day to crush. Crushed grain goes stale faster than intact grain, so — if feasible — it’s best to leave your grain whole until brewing day.
Water Treatment
Water is the most abundant ingredient in beer. Without good water, you cannot make good beer. In addition, the types and amounts of minerals dissolved in the water will influence the success of your mash.
Water treatment is one of the most potentially complicated parts of all-grain brewing. Many homebrewers go to great lengths to treat their water. For example, some may try to make their water more closely resemble the water from famous brewing centers. The “Burton salts” you may have seen in your homebrew shop contain roughly the same proportion of minerals found in the water of Burton-on-Trent, the British town long famous for its pale ales.
You can, however, take a relaxed approach to water treatment and perform successful mashes. Just about any water that is safe for drinking and tastes good can be used for mashing if you deal with two important variables: levels of chlorination and levels of calcium ions.
Most municipal water plants treat their water with some type of chlorine. The flavor of chlorine detracts from that of beer, while chlorine — or chlorinated substances — can interfere with some of the chemical reactions in mashing. If you can taste chlorine in your water, you should filter your water through a carbon filter. Boiling eliminates chlorine but not newer chlorinated compounds, called chloramines, that many city water departments are now using.
Optimally, your water should have between 50 and 100 ppm calcium when brewing most beers. However, many world-class beers are made from waters that have much more or less calcium. The waters of Pilsen, Czechoslovakia have between 5–10 ppm calcium. The water in Burton-on-Trent contains 268–295 ppm calcium.
Knowing this, I think it is reasonable to urge brewers who don’t want to fiddle with the details of water chemistry to just go ahead and use their local water and see what happens. It’s unlikely your water is softer than that of Pilsen or harder than Burton-on-Trent (although my local water supply has that distinction). Odds are, everything will go fine. I certainly wouldn’t let water chemistry worries dissuade you from trying all-grain brewing.
If you do want to ensure your calcium levels are close to optimal, try the following. First find out the level of calcium in your water. To find out your calcium levels, contact your local water department. Alternately, you can get water hardness tests at most homebrew shops. Performed correctly, these provide reasonably accurate estimates of water hardness.
If you have soft water (less than 25 ppm calcium), add calcium in the form of gypsum or calcium chloride. One gram of gypsum adds 61.5 ppm calcium to one gallon of water. If your water is between 25 and 150 ppm calcium, just leave it alone. If your water contains over 150 ppm, dilute it with distilled water. You should not use water from your water softener if you have the type that exchanges sodium ions for calcium ions, as you will end up with too much sodium in your beer.
Mashing In
The first step of mashing is called the mash in. This is when the crushed grains are combined with hot water. In a single infusion mash, the temperature of the water and grains should be between 150 and 158 °F (66–70 °C) after they have been mixed. Temperature is the second key variable to a successful mash.
The temperature of the mash influences the fermentability of the wort. Mashes held at the lower end of the temperature range yield more fermentable worts than mashes held at the higher end of this range. So, if you’d like to make a dry beer, mash at 150–153 °F (66–67 °C). If you like a sweeter beer, mash at 155–158 °F (68–70 °C). Your choice of ingredients also effects fermentability, with specialty grains contributing less fermentable sugars than base malts.
Because the grains are cold compared to the hot water, the water used for mashing (also called strike water) must be hotter than the mash temperature. If your grain is at room temperature, try heating your strike water to 10 °F (5 °C) greater than your desired mash temperature. For example, if you want to mash in at 152 °F (67 °C), heat your strike water to 162 °F (72 °C).
There are two ways to mix the water and grains. The first is to add all the crushed grains to your mash tun, then slowly add the strike water until you are mashed in. Be sure to stir well with a large spoon or a mash paddle as you mix the water into the grains. If you don’t, you will leave dry pockets of crushed grain in the mash. The starch in these pockets won’t convert to sugar.
The second method of mashing in is to mix small amounts of grain and water together and add this “mush” to your mash tun. Take two pounds or so of crushed grain in a small pot and add hot water until it’s roughly the consistency of oatmeal. Then dump it in your mash tun and repeat until you’ve used up all your grain. Once all the grain is in, add water until there is about an inch (2.5 cm) of water standing above the grains.
Either of these methods works, although the second is easier if you do not have a spoon or mash paddle large enough to easily stir your entire mash. In either case, you should add enough water to cover your manifold or false bottom before you add any grain to your mash tun.
Overall, you will need about 1.25 quarts water per pound of grain (2.6 L per kg) to mash in. For example, for 10 pounds (4.5 kg) of grain, you would need 12.5 quarts (12 L) of water to mash in. At this water-to-grain ratio, the grains will be completely wet and the water level in your mash tun will be an inch (2.5 cm) or so above the level of the grain bed.
In order to hit your desired mash temperature, you should work quickly when mashing in to avoid losing lots of heat to the environment. There’s no need to rush, but work purposefully. If you pre-heat your mash tun with hot water before mashing in, you will minimize heat loss due to heat transfer to your mash tun.
Before mashing in, I fill my mash tun with hot water (170 °F/77 °C) and let it sit for five minutes. (I use this water later for sparging.) I also put my mash paddle and the beer pitcher I use for a hot-water ladle in that water so nothing that touches the strike water or mash will take heat from it. (This might be a bit of overkill on my part, but I like the mash in stage to go smoothly.)
Always have some extra hot and cold water on hand when mashing in. For 5-gallon (19 L) batches, having a couple gallons of boiling water handy will allow you to boost your mash temperature if you fall short at mash in. Likewise, room temperature water can be used to lower your mash temperature if you overshoot. When adjusting mash temperatures, go easy on the hot or cold water additions. Add a couple pints of water and stir thoroughly each time you do. Then check the temperature at a couple different places in the mash. It’s not the end of the world if it takes a couple minutes to adjust your mash temperatures
Mash pH
The pH of your mash is the third important variable. The pH of a mash should be between 5.2 and 5.6. With any luck, you won’t have to do anything to adjust it. After mashing in, draw off a small sample of wort and check the pH. The simplest way to do this is with pH papers, which are available at most homebrew stores. If the pH is over 5.6, stir one teaspoon of gypusm into the mash. If the pH is below 5.2, stir in one teaspoon calcium carbonate into the mash. Retest pH and add one more teaspoon if needed.
The Starch Conversion Rest
Once you’ve mashed in, and adjusted the temperature if necessary, let the mash stand for stand 45–90 minutes. If you are using a picnic cooler, close the lid during the mash to conserve heat. If you are using a pot or kettle-type mash tun, put a lid on it and insulate it with towels. (Some mash tuns have specially-fitted “mash jackets” for insulation.)
If your mash tun is well-insulated, the temperature should only drop by a degree or two during the rest. If your temperature drops more than this, you can boost it by stirring in some boiling water. Alternately, if your mash tun is heatable, you can simply add heat. Be sure to stir when heating and watch that you don’t overshoot. You should turn off the heat when you are within 2–3 °F (1 °C) of your target and let the heat in the metal near the heat source radiate into the mash.
In many commercial breweries, the mash is stirred continually by rotating paddles. Constant stirring is not necessary for homebrewers, but stirring your mash a few times during the starch conversion rest can improve your efficiency. However, watch out for heat loss when opening up your mash tun and stirring. Keep some hot water on hand in case you lose too much heat when you open up the mash tun for stirring.
During the starch conversion rest, the grain will absorb water, the starch in the grains will dissolve and enzymes from the malt will degrade the long starch molecules into simpler sugar molecules that the yeast can use during fermentation.
One way to test if the mash is complete is to perform an iodine test. To do this, take a couple drops of wort and place it on a white plate. Take care to exclude any solids from the wort sample. Then, add a drop of iodine solution to the wort. If the iodine changes color to blue, purple or black, then starch is still present. Almost any solution with iodine in it, including iodophor, can be used for this test. To see what a positive reaction looks like, dissolve a pinch of corn starch in water and add a drop of iodine. (To see what a negative reaction looks like, add a drop of iodine to a drop of water.) If you get a positive result after mashing, which is unlikely, check your mash temperature and extend your mashing time. Keep performing iodine tests until the test results are negative.
After the starch conversion rest is complete, you have two options. The first is to proceed directly to separating the wort from the spent grains (lautering). The second option is to perform a mash out.
When you mash out, you add boiling water to the mash to raise the temperature to 168 °F (76 °C) and let it rest for five minutes at this temperature. Mashing out makes lautering easier and may increase your extract efficiency slightly. Also, mashing out destroys the enzymes in the mash. If you mashed for lower fermentability (for a sweeter beer), mashing out ensures that fermentability won’t increase if the temperature of the grain bed drops to the lower 150s (around 65 °C) — the mashing range for higher fermentability — during lautering.
Once the mash is complete, you need to drain your wort from the grain bed. Proper wort separation is the last of the four important variables.
