CHAPTER THREE
MASHING AND STEEPING
Whether mashing an all-grain batch of beer, or steeping a bag of grain in preparation for an extract batch, the home brewer goes through the same process as the professionals: using heat to activate enzymes in water—a substrate that the grains work well in. These enzymes then break down long, complex hydrocarbon chains—that we know as starch—into small, bite-sized (for yeast) molecules: glucose, maltose, and maltotriose. This process utilizes the wonderful, dynamic range of color, flavor, and texture available in barley malt.
Problems here usually occur when temperatures aren’t being met or maintained, when barley isn’t crushed just right, or simply when the brewer has a forgetful moment. Most issues that a brewer runs into at this point in the process are easy to recover from. You’ll still have beer at the end, but may have a much longer afternoon in front of the brew kettle than you originally planned. Having some homebrew handy on one of these afternoons can of course make them move by much more quickly!
22 | The alpha-acid content in my hops is different |
CAUSE
While the same variety of hops will generally have a similar range of alpha-acid content, different growing conditions can cause a variance in bittering potential. Alternately, a brewer may want to substitute different hops into a recipe while maintaining the same bitterness character.
SOLUTION
The trick to making this calculation is to understand alpha acids.
The alpha acid listed on the package of hops is the percentage of the dry weight of the hop that is alpha acids. Alpha acids undergo a chemical reaction during the boil, in which humulone is rearranged into trans-and cis-isohumulone, both of which are perceived by humans as bitter. The higher the alpha-acid content of the hop is, the fewer hops you need to create the same amount of bitterness.
On a homebrew scale, the easiest way to make this calculation is to multiply the alpha-acid content of the hop listed in the recipe by the number of ounces or grams it calls for to find the Alpha Acid Units (AAU), and then divide the AAU by the alpha-acid content of the new hop.
For example, if your recipe calls for 3.5 oz (100 g) of East Kent Goldings (5.5 percent AA), but you would like to substitute Bramling Cross (4.2 percent AA), calculate the following:
3.5 × 5.5 = 19.25 AAU
19.25 ÷ 4.2 = 4.6
It will take 4.6 oz (130 g) of Bramling Cross (4.2 percent AA) to create the same amount of bitterness as 3.5 oz of East Kent Goldings (5.5 percent AA).
Whole-leaf hops, such as these, can be stored safely in an airtight container. The bittering potential of your hops is dependent on the growing conditions of this natural product.
23 | I forgot to add my extract/all of my extract |
CAUSE
Brew days can be busy and distractions can easily pop up, meaning even the most careful brewer can forget a step now and then.
SOLUTION
Even though this seems like an egregious error—particularly if you’re an extract brewer—it really isn’t as awful as it might seem.
If you’ve reached a boil already, go ahead and add your extract. In fact, many brewers only add extract in the last 10 minutes of the boil—long enough to sanitize the extract, but not long enough to cause excessive caramelization from boiling all that sugar. Take care when adding extract into boiling liquid, as the liquid may boil over, or splash onto and burn your skin. In addition, if you add the extract too quickly, it may sink to the bottom and scorch.
The only time you should not add your extract is post-cooling, at least not without some amount of processing. Once wort is cooled, utmost care should be taken to avoid contamination with any microbes, and while extract is often packaged and sealed very well, there is always the small chance that bacteria or mold spores will hitch a ride into your fermenter.
If you must add extract into the fermenter, take the time to dissolve it in water and boil for at least 10 minutes, then cool it before adding. This will help dissolve the extract into water, and make it easier for the yeast to metabolize it. It will also help protect you against infection risk.
It is important to always stir the liquid while adding malt extract to the boil to avoid scorching or boil-overs.
24 | I’m not sure how to use grain in my extract brew |
CAUSE
Partial-mash recipes often come with precious little protocol beyond how much grain to use, leaving the brewer to make assumptions about how to use grain in any given recipe.
SOLUTION
Most extract recipes are actually partial-mash recipes—containing a few pounds of grain for added character—but most don’t give much consideration to the content of grain, aside from adding color and a bit of extra flavor.
It’s often best to consider partial-mash recipes as a “mini-mash.” If grain steeps at the correct temperature—150°F–154°F (65°C–67°C)—any enzymes in the barley will activate and begin to break starches down into sugar. While the grain is floating in liquid, any residual sugar—or any sugar that is formed from starches—will begin to dissolve.
To best add grain into your extract brew, steep grain for at least an hour in as little liquid as possible—try 1.5 quarts (approximately 1.4 liters) per pound of grain. Consider adding some base malt into the partial-mash grist, in addition to specialty malts, to contribute enzymes and help break any available starches down into sugar.
When removing grain from the wort, allow time for liquid to run out of the grain—it’s all valuable sugar! Consider dissolving your extract into the water that has drained out of the grain bags before heating, so that enzymes can work on breaking down any complex sugars that have been introduced by the extract. If possible, pour warm water—170°F (77°C)—over the grain to help extract sugar.
No matter what, take your time! Extract brewing is sometimes thought of as a shortcut around mashing, but using the principles of a good mash while making an extract brew can produce superior beer.
In this picture crushed grain in a nylon bag is being added to water. The drawstring at the top means that this bag can be used for multiple brews.
25 | How much water do I use in my all-grain mash? |
CAUSE
The amount of water used in an all-grain mash can depend on the recipe, and whether there is space in the mash tun for the requisite grain and water. Brewers may not know the best water-to-grain ratios.
SOLUTION
A loose mash—a lot of water—will favor proteolytic enzymes, which break down proteins and denature enzymes, meaning that starch conversion may happen a bit slower in looser mashes. It can also be difficult to form a mash bed in a loose mash because so much of the grain is floating.
A thick mash—not much water—will favor diastatic enzymes, which help break down starches into sugars, meaning that starch conversion may happen quickly, but lautering may be more difficult because proteins have not been efficiently broken down or denatured.
In general, when creating an all-grain mash, the sweet spot is between 1.25 quarts (1.2 liters) of water per pound of grain and 1.75 quarts (1.65 liters) of water per pound of grain. That range allows enzymes to work efficiently from both ends, creating a well-converted mash that allows water to pass through the mash bed, as required for a good runoff.
In certain brewing conditions—big beer in a small mash tun, lack of secondary water vessels, for example—it may be necessary to brew with as low as a 0.75:1 ratio, or as high as a 2:1 ratio. In the end, good beer will still be achieved, though it may require a little more patience. In circumstances where mash ratios are not ideal, consider mashing for a longer amount of time to allow enzymes time to work in the mash bed.
It is important to insure that there is enough room in a mash tun for the extra water added during the lautering process.
26 | I can’t get a filter bed to form in the mash |
CAUSE
Runoff is too quick, or mash temperature was too low, producing a very cloudy wort or a lot of husks and debris entering the kettle.
SOLUTION
First, be sure that the mash temperature is correct. Unless a specialty recipe is being brewed, shoot for between 150°F and 154°F (66°C and 68°C) for most mashes. If you can, heat the mash bed to 170°F (77°C) before runoff. This will arrest enzymatic activity and denature many proteins that may cause a sticky runoff. Otherwise, be sure that the sparge water is around 170°F (77°C). The mash bed will slowly come up to temperature as lauter progresses.
If the grist consists of a large amount of high-protein grain like wheat, rye, or oats, consider doing a small step mash. A rest between 98°F (37°C) and 113°F (45°C) will activate the enzyme beta glucanase, which will help break down beta glucan. Beta glucan is a gummy cellulose that can create a cement-like mash. A 20-minute rest should be enough to keep your mash beta glucan-free.
Next step is recirculation. Transfer 5 to 10 percent of the volume of your mash into a vessel (your kettle or another pot) then return it to the top of the mash. Recirculation establishes a good mash bed by running liquid slowly out of the bed, allowing the barley husks to form a natural filter. It also removes protein and bits of barley husk that may have fallen below the false bottom of your mash tun, and places them on top of the mash bed, filtering them out while retaining the valuable sugar present in first runnings.
Good recirculation, and a slow start to a runoff, can help establish a good mash bed—once wort is free of any visible bits of grain, you can slowly increase the runoff speed.
A good filter bed requires the right temperature mash. This is vital for good sugar conversion, and an easy runoff. It is helpful to keep a thermometer to hand throughout the boiling process to insure the mash temperature stays consistent.
27 | The grain bed collapsed during lauter |
CAUSE
Water is no longer running through the mash bed, or proteins present in the mash have caused a “stuck mash.”
SOLUTION
This is often associated with high-protein mashes with adjuncts that contain a lot of gummy proteins, like wheat, rye, or oats. However, a stuck mash or collapsed bed can happen on any beer. First, check Problem 26 for how to establish a good filter bed.
Check the grain bed has enough water in it. In a small mash tun, the top of the liquid in the mash tun should be between 0.5 inches and 1 inch(1.3 and 2.5 cm) above the top of the grain bed. This insures that the grain floats in the water rather than collapsing against the false bottom. Also check your sparge water is hot enough. You should be sparging at 170°F (77°C).
If you’re brewing with high-protein grains, add rice hulls to help create channels through the mash bed. Ideally, these are added before the mash starts, but stirring them into a stuck mash can often help get liquid moving again. Stir them so they distribute throughout the mash bed, the closer to the bottom the better, then recirculate wort and re-establish a filter bed.
Underletting can often restart a stuck mash but is challenging if you don’t have robust equipment (or a pump). Push some hot water into the mash tun from the bottom up, floating the mash on a column of sparge-temperature water, then stir the mash bed, scraping any gummy proteins from the false bottom, and recirculate wort to establish a new filter bed.
If this is a consistent problem, you may be crushing your grain too finely (see Problem 16).
This picture shows recirculation in action. Brewers recirculate wort by extracting 5 to 10 percent of the volume from the bottom of the mash bed, transferring it to another clean, uncontaminated vessel, and returning it to the mash tun. They do this before starting runoff in order to insure clear wort and a stable mash bed.
28 | My infusion mash won’t reach target temperature |
CAUSE
Strike water has not been adjusted for the ambient temperature of grain or equipment. Even if 154°F (68°C) water is used, if strike water is only 68°F (20°C), this will not result in a mash temperature of 154°F.
SOLUTION
To correctly achieve mash temperature, it’s important to remember that heat will be lost when introducing hot water to cooler grain. While it’s easy to use brewing software or an online calculator to find the best target mash temperature, this is also an easy calculation you can do at home. You need to know the number of quarts of water per pound of grain being used (Q), the current temperature of the grain (C), and the target temperature of the mash (T), and apply it to this equation:
Water Temp = (0.2÷Q) × (T – C) + T
For instance, if you have 1 quart of water per pound of grain, the grain is at room temperature, 68°F (20°C), and your target mash temperature is 154°F (68°C):
0.2 ÷ 1 = 0.2
154 – 68 = 86
0.2 × 86 = 17.2
17.2 + 154 = 171.2°F
However, bear in mind that the temperature of your equipment may also play a role. This equation will allow a ballpark estimate, but if hot water is being added to a cold, metal mash tun, additional heat may be lost. It’s always best to keep a thermometer handy to be sure that you’ve met mash temperature correctly.
Temperature management is one of the most important parts of brewing, so a quality kettle thermometer is a vital piece of brewing equipmement.
29 | My mash won’t hold temperature |
CAUSE
A poorly insulated mash tun, or a mash tun made of the wrong material, allows heat to escape the mash, leading to poor efficiency or stuck mashes.
SOLUTION
The mash temperature should remain constant through the entirety of the mash to insure that enzymes remain active to break down all the available starches into sugar. In most cases, the thermal mass of the grain and the water together should retain enough heat to stay relatively consistent through an hour mash, but that is not always the case.
While a mash tun could be any vessel with a false bottom in it, most homebrew mash tuns are made from insulated water coolers which are meant to keep ice and water cold. They are equally effective at keeping a mash warm.
When using a single-walled pot or kettle, which conducts heat much better than insulated plastic, the brewer should monitor temperature to be sure it doesn’t dip, and if it does, reheat the mash tun if possible. However, care should be taken not to scorch the mash, but to be sure that heat is transferred as evenly as possible throughout the grain bed.
If a direct heat source is unavailable, a homebrewer can place a copper-coil heat exchanger inside the mash tun, and cycle mash-temperature water throughout the coil to maintain temperature.
Brewers need to regularly monitor mash temperature to avoid stuck mash. A stuck mash can mean a very long day, and possibly mean that off-flavors will be extracted from grain.
30 | My mash bed keeps running dry |
CAUSE
Poor flow management during lauter can empty a mash tun too quickly, collapsing and compacting the mash bed and reducing efficiency.
SOLUTION
Lautering is relatively easy and should be a balance between temperature and time. When lautering, the water level should always be just an inch or so above the level of the grain bed, and the grain bed should never run dry.
Since the purpose of lautering is to extract sugar from the barley in the vessel, it’s important that the water has enough contact time with the barley to dissolve that sugar. When all else fails, close the runoff valve on the mash tun, then reopen it slowly so that a mere trickle runs out. On a homebrew scale, it should take about 30 minutes to run off 5 gallons (19 liters) of wort, or about 1 hour to run off 10 gallons (38 liters) of wort.
Some brewers lauter using a technique known as “batch sparging.” Batch sparging is the act of topping off the mash with sparge-temperature water, running off until the mash is dry, then filling the mash tun with sparge-temperature water again, repeating until volume is met. In this case, conventional wisdom is that there is no reason to run off slowly, since all the grain will meet hot water again, but a slow runoff may lead to higher efficiency and cleaner wort.
Allowing the mash bed to run dry during runoff can collapse the grain bed, making it very difficult to then lauter.
31 | I don’t know when to stop lauter |
CAUSE
It can be difficult to know intuitively when to stop lautering. There are several schools of thought to follow, none of them perfect.
SOLUTION
There are three ways to figure out when to stop lautering, each with their own issues:
• Finish lauter when the wort in the kettle reaches the predicted/desired pre-boil gravity. While this means you will have hit a recipe target, depending on the efficiency of your mash you may run much more, or much less, water through it than needed, leaving you with much more, or less, wort than you intended. Remember that wort layers easily, with the densest wort at the bottom of the kettle and the least dense wort on top. Mix the kettle thoroughly before taking a gravity measurement.
• Finish lauter when the gravity of the runoff water reaches 1.008. In theory, the likelihood of extracting tannins from the husks of the barley, rather than just sugars, increases below this point. There’s still a risk of lautering more, or less, wort than is needed. Unless you’re brewing an extremely low-gravity beer, the likelihood of tannin extraction is low.
• Finish lauter when you have the correct amount of liquid in the kettle—the size of the batch with extra wort to make up what you will lose in evaporation. While you may not always hit your gravity targets perfectly, you will have achieved one of the important goals: to have the correct batch size. If you maintain a consistent level of mash efficiency, this third option is an excellent method, particularly for creating a specific amount of recreatable beer.
The alternative to batch sparging is fly sparging. Fly sparging is a method used by most commercial breweries and all-grain homebrewers. Using a simple device such as the one pictured here can make fly sparging at home an easy possibility.
32 | My mash temperature was way too cold |
CAUSE
Strike water was not warm enough to achieve target mash temperature. Mash is cooler than anticipated, leading to poor conversion, loss of efficiency, or a thin-bodied beer.
SOLUTION
The most efficient starch conversion in modern mashes falls between 150°F and 154°F (66°C and 68°C). If your mash temperature is too low, the easiest solution is to add more hot water to the mash. However, given the size restrictions of your mash tun this may not be possible. It takes much more energy, thus more water, to raise the last few degrees of a mash. It may require the addition of very hot, even boiling, water. To find out how much water to achieve a specific temperature, you need to know the desired temperature (T), the temperature of the water you will add (W), the current temperature of the mash (M), the amount of grain in the mash (G), and the quarts of water currently in the mash (Q).
Amount of Water to Add = (T – M) × (0.2G + Q) ÷ (W – T)
If you have a 140°F (60°C) mash, and you’d like to achieve 154°F (68°C), using water at 200°F (93°C), and there’s 12 lb of grain (5.4 kg) and 12 quarts (11.4 liters) of water:
(154 – 140) × (.2 × 12 + 12) ÷ (200 – 154)
Or
14 × 14.4 ÷ 46 = 4.4 quarts of 200-degree water
If there is not enough room in the mash tun, it may be necessary to run wort off, carefully bring it to a boil, and re-add it to the mash in a process known as “decoction mashing.” The same calculation applies, but bear in mind that the drawn-off liquid is no longer in the mash.
33 | My mash temperature was way too hot |
CAUSE
Strike water was too hot to achieve target mash temperature. Mash is warmer than anticipated, leading to poor conversion, loss of efficiency, or wort with low fermentability.
SOLUTION
If your mash temperature is too hot, you must act quickly to reduce the temperature, or you run the risk of denaturing enzymes that are important to the mashing process. Enzymes do not denature instantly, but the warmer the mash, the faster the denaturing process.
If you are a few degrees off from your target, it may be more efficient to stir the mash vigorously, bringing mash from the middle of the bed to the top. This releases energy from the mash, as steam and heat rises from the top of the mash bed, and can easily reduce the overall mash temperature by a few degrees.
If your mash temperature is much higher than intended, you may need to add cold water, then proceed with the same formula used to increase mash temperature (see Problem 32).
Amount of Water to Add = (M – T) × (.2G + Q) ÷ (T – W)
Thus, if you have a 170°F (77°C) mash, and you’d like to achieve 154°F (68°C) using water at 60°F (16°C), and there is 12 lb (5.4 kg) of grain and 12 quarts of water:
(170 – 154) × (0.2 × 12 + 12) ÷ (154 – 60)
Or
16 × 14.4 ÷ 96 = 2.4 quarts (2.3 liters) of 60°F (16°C) water
If there is not enough room in the mash tun, it may be necessary to chill water using ice (or even add ice to the mash bed) to achieve a significant temperature drop without overflowing the mash tun. As always, be sure that temperature is balanced throughout the mash bed.
34 | What do I do with my spent grain? |
CAUSE
After mashing in, spent grain—the wet barley leftover from the mash—can be a major waste product that is difficult to dispose of.
SOLUTION
Think of spent grain as a by-product rather than a waste product. There are many alternatives to throwing away spent grain. In many municipalities, it is frowned upon to have large amounts of biodegradable waste. Commercial brewers can send their spent grain to a farm to be used as animal feed, but at home you have alternative options.
• If you have the space, spent grain makes excellent compost that breaks down quickly because of its high fiber and high moisture content. Make sure it’s aerated and mixed in well so that it doesn’t get smelly.
• A little spent grain can add a lot of flavor and texture to homemade bread. However, it has a lot of moisture and not much in the way of gluten, so use sparingly or it may stop your bread from rising.
• Homemade crackers can be easier to make than bread because they don’t rely on rising action.
• Mix in a little peanut butter and sweet potato to make nutritious and delicious treats for your dog.
• Some intrepid brewers use spent grain as a medium for growing mushrooms (using proper pasteurization and treatment).
• Mixed with paper pulp or sawdust, compacted, and dried, spent grain can be used as a source of heat.
• Give your waste to a local farm for their compost, or as a supplement to their animal feed—it may net you a few vegetables in trade if you’re a good negotiator!
Whatever you do, always do proper research and preparation to insure safety.
Spent grain has many uses, but it can also be very hot immediately after runoff, so care should be taken when handling it.