Serving the home brewing community since 1991

Taking the Fear out of Mashing

If you’ve already begun brewing with malt extract kits, you know that extract brewing is pretty simple. All-grain brewing sounds much more complicated and time consuming, so why bother?

There are two very good reasons:
Mashing, or all-grain brewing, is less expensive than extract brewing; usually much less, after a modest investment for some equipment. It also gives you almost total control over the finished product. You produce precisely the kind of beer you want, instead of depending on the ingredients and processes used by a kit manufacturer.

So why don’t more homebrewers mash?
We think it’s because many of the available books on the subject are too technical for a novice. We prefer the “Relax, don’t worry” approach. All-grain brewing is like any other industrial process; you can study for years and still not know everything about it, but you can follow some simple instructions at home and achieve basically the same result as big commercial breweries. This page contains all you need to know to begin mashing, saving money, and making better beers.

Don’t be concerned about step mashing, decoctions, or complicated procedures and fussy temperature and chemical adjustments. Those procedures were necessary years ago, due mainly to the limited availability of top quality brewing malts. Today, with fully modified two-row malts readily available through homebrew supply dealers, you can use the simplest procedures with complete confidence. The method used by most all-grain homebrewers today is the time-honored English method called single infusion. You just mix the grist (ground malt) with hot water. After mixing, leave it alone for an hour or so to let the natural enzymes in the grain convert the starches to sugars. The only technical aspects are taking the temperature of the mash, a simple test for starch conversion (and even that’s optional), and rinsing the sugars from the spent grain. The equipment and procedures are also relatively simple. No other techniques are necessary for most homebrewers, but once you feel comfortable with a single infusion mash, even the more complicated techniques will be well within your reach.

What you’ll need:

Batch size:
5 (U.S.) gallons (19 litres)

Some experience with extract brewing
Familiarity with basic process of making beer

Mash tun
Lauter tun
Large stirring spoon
White porcelain saucer
Thermometer reading to at least 200 °F (93 °C)
Two small pans
Boiling pot of at least 5 gallon (20 litre) capacity (If possible, try to find an 8 gallon (36 litre) pot)

Tincture of iodine (first aid section of a drug store or chemist)

Brewing water (9 or 10 gallons) (34-38 litres)
Well modified 2-row barley malt, ground to crush the grain while leaving the husks mostly intact (about 10 pounds) (4.5 kilograms). Typical malts are Klages, Harrington, English or Belgian 2-row, Pale Ale, and similar “base” malts.
Other adjunct grains as desired (according to your recipe) such as crystal, chocolate, roasted barley, etc.


Grist is the brewer’s term for crushed malted barley. The malt should be crushed to the point that almost all the grains are broken, but not so much that the outer husks are ground to powder or the insides ground to flour. It’s better to lose a little efficiency with a coarse grist than to risk a stuck sparge from too much flour in the grist (“stuck” means the straining equipment becomes clogged). Most homebrewers will eventually buy a mill of some kind. It can pay for itself very quickly and can be easily motorized with an electric drill. The South American (“Corona”) corn mill is cheapest, but difficult to adjust, impossible to keep in adjustment, and less efficient than roller mills. Several more suitable mills are now available, and we encourage you to check them out at better homebrew supply stores. The PhilMill is a perfect example. A beginner might take advantage of the fact that many suppliers will mill the grain for a nominal charge, using a roller mill to produce a superior grist. Try to avoid the bagged, pre-crushed grain often seen in stores. Once milled, the grist can go stale, and is open to infection. It’s also impossible to tell how old it is, or how well modified. Dark malts, such as black patent, chocolate, or roasted barley, don’t require mashing, so are best lightly cracked and added to the mash just before sparging.

The Process

Striking is mixing the grist with hot water. The hot water dissolves the starches in the grist and activates the enzymes that will convert the starches into sugars. By controlling the temperature, different effects are possible.

Here’s the simple procedure:

Heat about 3 gallons (11 litres) of water to 170 °F (77 °C).

Ladle a pan of water into the mash tun. Use the other pan to add some grist. Alternate pans of water and grist, stirring between additions. Try to maintain a porridge-like consistency by adding extra grist or water as needed. It’s usually better to have a thin, watery mash mixture than an overly thick, dry mash.
Check the temperature of the mash. It should be within a few (plus or minus) of 150 °F (66 °C). Add hot or cold water as necessary to bring the mash as close as possible to this range. Close the mash tun to hold as much heat as possible.

Starch Conversion — The Iodine Test

After about 30 to 45 minutes, most of the starches in the grain have been converted into sugars. Leftover starches can cause a hazy appearance in the beer, but a simple test can tell you when all (or nearly all) the starches have been converted.

Stir the mash with the spoon, then let a few drops of the liquid (but no solid particles) fall from the spoon onto the white saucer. Add a drop or two of iodine to the wort in the saucer. If the iodine quickly turns black or dark blue, there is still some unconverted starch in the mash. Wait ten minutes, then try the test again. If the iodine remains about the same orange/brown color it was, no starch is present in your sample. Now the next step, lautering, can begin.

Caution: Never return the contents of the saucer to the mash, as it has been contaminated by the iodine. Wipe the saucer clean immediately.

Lautering & Sparging:


Lautering is the process that separates the newly converted sugars in the grain from the husks and other solids. Ladle the mash from the mash tun into a separate vessel (the lauter tun) equipped with a false bottom. Allow the mash to settle for about ten minutes.

Lautering has two phases:
Vorlaufing, which removes most of the grain particles from the sweet wort and lets the husks form a natural filter bed over the false bottom; and sparging, where the hot water is sprayed on the grain while the sweet wort is drained from beneath the false bottom.

1. Heat the sparge water. Up to 5 gallons (20 litres) should be heated to between 170 and 180 °F (77 to 82 °C).
2. Start the vorlauf operation by opening the drain of the lauter tun, and slowly fill a pan. At first it may be cloudy and full of grain particles. When the pan is full, stop the flow and very gently return the wort to the top of the mash. Repeat this cycle until few particles are found in the wort and the cloudiness begins to diminish.
3. Begin to drain the wort slowly into the boiling pot. When the liquid level of the mash falls to just above the top of the grain bed, the sparging operation may begin. Allow at least 30 minutes for sparging.
4. Sparging consists of applying hot water to the mash to replace the wort that drains out of the lauter tun. This dissolves and rinses the sugars from the spent grain. Even distribution of the sparge water is the key to efficient sparging. This can be accomplished best by gently sprinkling the hot water evenly over the mash.
5. Sparging ends when the sparge water runs out or the pot is filled to its safe boiling point. Never squeeze, press, or wring out the spent grains. There is no need, since almost all of the sugar is gone and undesirable flavors can come from the husks.


Boiling and the rest of the process can now proceed just as with any extract brew. You have successfully duplicated the process used by every major brewery in the world, you have given yourself (rather than an extract manufacturer) total control over the recipe formulation, and you’ve also saved quite a bit of money!

Mash Tuns

The mash tun is a vessel that contains the grist/water mixture (the mash). Generally, it should be at least large enough to hold the mash, assuming 2.5 pounds of grain per gallon (2 kilograms of grain per 7 litres of capacity). A standard 5 gallon bucket should hold a mash containing up to 12.5 pounds (5.75 kg) of grain. It should also be well insulated, or capable of being insulated. A common picnic cooler is just about ideal; it’s very well insulated, generally large enough, and easy to clean. The round variety often seen at construction sites is particularly well suited to this purpose. Any simple plastic bucket can be insulated with a blanket or sleeping bag. The temperature loss during the conversion time won’t be enough to seriously affect the outcome.

Lauter Tuns

A lauter tun is the one piece of equipment that extract brewers may not already have on hand. It can be thought of as a strainer used to separate the sweet wort from the mash. Four kinds are used in homebrewing: The grain bag is literally a bag that fits inside a bucket or cooler. The bucket should have some sort of drain. The sides of the bag are made from canvas or nylon. The bottom is a screen or mesh. Its major drawback is a tendency for some of the sparge water to bypass the grist, seeping between the grain bed and the bag, or between the bag and the walls of the bucket, thereby reducing efficiency.
The double bucket system consists of two nested 5-gallon plastic buckets. The upper bucket’s bottom has a great many drilled holes, and the lower bucket has a drain. This system needs a lot of foundation water (a gallon or so) to submerge the bottom of the upper bucket, in order to prevent a stuck (undrainable) mash. That can be a significant drag on efficiency. Also, the level of liquid in the upper bucket must never rise above the top of the lower one, or it will overflow. Capacity is limited to less than about 10 pounds (4.5 kg) of grist. On the other hand, it has the advantage of being made at home with common materials and tools.

The manifold system is usually made from soft copper tubing wound into a coil that fits inside a bucket or cooler. The coil is drilled with many small holes or slotted with a hacksaw. One end is closed by crimping or capping. The other end is fitted to a hose leading through a hole in the bucket.
A T-shaped manifold can also be used, with plastic pipe substituted for copper. The size and length of the tube limit the drain area. That can lead to slow or stuck mashes. Solids can collect near the drain, severely limiting the flow. Cleaning the tube presents problems, because drill or saw burrs retain solids that can harbor bacteria.

The best system mimics the equipment used in commercial brewing. This is a false bottom made of a drilled or slotted plate, supported just above the floor of the vessel. Many drain holes are spaced over a wide area. There are no constrictions and it’s easily cleaned. Since the false bottom is only a fraction of an inch above the real bottom, little or no foundation water is needed, allowing you to utilize all the sparge water.

Phil’s Lauter Tun and Phil’s Mini Lauter Tun are examples of this type.The Sparger Sparging can be as simple as hand ladling the hot sparge water onto the mash, or as sophisticated as a rotating sparge arm fed by an elevated sparge water bucket. The only difference is convenience and efficiency. Ideally, the sparge water should be applied so the liquid level is just under the surface of the grist. This lets the water support the grain bed without pressing it down, and assures that channeling is minimized. The flow should be evenly distributed at a uniform speed. Unfortunately, this is difficult to control, so it’s better to keep the mash slightly covered with water.


Try not to rush sparging. In a typical homebrewer’s setup, 5 gallons of sparge water should last 30 to 40 minutes; otherwise efficiency suffers. You want the residual sugars in the grain to dissolve in the fresh hot water before draining out of the lauter tun. All sparging methods (except the first) require a bucket with a drain to hold the sparge water before it enters the lauter tun. Five methods are commonly used:
Hand ladling is certainly inexpensive, but very labor intensive. Wherever the water is poured, it tends to bore channels into the mash. These channels form an easy path for the water to bypass much of the mash, so efficiency suffers.

The open drain method requires a sparge bucket fitted with a drain. It’s filled, usually by ladling, from the brew kettle which is later used to boil the wort. The sparge bucket is elevated so the drain hangs over the center of the mash. You repeatedly open and close the drain, keeping the mash flooded as the sweet wort is drawn off. The falling water can bore channels in the mash, hurting efficiency just as with hand ladling, although a saucer or shallow dish resting at the top of the mash can limit this problem.

Attaching a hose with a sprinkling head (the watering can variety) to the sparge bucket can eliminate most of the problems associated with one stream of water. The mash still requires flooding unless you continuously move the head about. The holes in a typical sprinkling head are usually too large, so the drain needs to be turned on and off frequently or the flood gets too deep.

A stationary sparge manifold can be constructed by coiling soft copper tubing with holes in its underside over the area of the mash. One end is capped and the other is attached to the sparge bucket hose. This will produce many fine sprays over a large area, but the spray will be strong at the start and weaker at the capped end. Unless the mash is flooded, each spray will bore a small channel into the mash and efficiency will suffer somewhat.

Commercial brewers use a rotating sparge arm that is drilled with tiny holes. The rotating action carries each hole over a large area. If the spray travels in the opposite direction of the arm’s rotation, the spray forms many rain-like droplets which cannot bore channels in the mash. The liquid level can then be held at the surface of the mash to maximize efficiency. Think of it as a specialized lawn sprinkler. See Phil’s Sparger for an example of this system on a homebrewer’s scale.

Mashing Systems

There are three mash methods: infusion, step mashing, and decoction. There are several variations of each. Only the basics for each method will be discussed here. Single infusion mashing is the method outlined in this brochure. The mash is performed in a well-insulated vessel, such as a picnic cooler. Then, after starch conversion, it’s transferred to a lauter tun, waiting 10 minutes for settling before vorlaufing.
Step mashing is used for incompletely modified lager malts. The mash must be heated to certain temperatures and allowed to rest at each before being heated to the next. The mashing is normally conducted in a pot on a stove. The primary challenges are stirring (to prevent scorching during heating) and accurate temperature determination.

Decoction mashing is the same as step mashing except that instead of directly heating the mash, a portion of it is withdrawn,, boiled, and infused back into the mash. It was developed before the invention of the thermometer, and is not recommended for beginners.

Boiling Capacity

Maximum efficiency in sparging usually requires that the sparge water equal the batch size (i.e., 5 gallons of sparge water for a 5 gallon (19 litre) batch). This will produce about 6 1/2 gallons of wort. A gallon will evaporate during the hour-long boil and a half gallon of trub is usually left at the bottom of the kettle.
For a number of reasons it is always best to boil the full batch. For a five gallon batch an eight gallon (32 quart/30 litre) pot is recommended. Sometimes boiling capacity is limited, but don’t look at that as an impediment to mashing.

A number of alternatives are available: Boil the first half of the batch separately from the second and recombine in the fermenter. Sparge only what can safely be boiled (the first 3 gallons of wort contain about 2/3 of the sugar) and either make a smaller batch or reinforce the batch with malt extract. Mash about 50% more grain than the recipe calls for, sparge about three gallons, boil, and cut the batch with boiled and cooled water added to the fermenter to make up the five gallons. If you’re currently a small-capacity extract brewer, try any one of these methods once and you should quickly develop the confidence to invest in a larger brewing capacity.

There you have it — a simple introduction to mashing! Follow the procedures outlined on this page and we predict you’ll quickly become an advanced all-grain brewer who makes better beer, saves money and has more fun doing it.