Grains on the Brain...

[brew captain]

Robert Kennedy
4/27/2014
 
What are grains?
In botany, grains and cereals are the fruits of the grass family Poaceae. There are over 10,000 domesticated and wild species in this ubiquitous family of plants, but only a small number of these are cultivated as food crops.

Common cereal grains include:
Barley Wheat Rice Spelt Rye Triticale
Farro Corn Flaxseed Millet/Sorghum Oats

Psuedo-cereal grains (nutritionally similar and used in similar ways to ‘true’ grains):
Amaranth Buckwheat Quinoa

Because grains are small, hard and dry, they can be stored, measured, and transported more readily than can other kinds of food crops such as fresh fruits, roots and tubers. The development of grain agriculture allowed excess food to be produced and stored easily which led to the creation of the first permanent settlements and the division of society into classes. Oh, and BEER of course!

For the sake of this discussion we will focus only on grains typically used in brewing:
Barley Wheat Rye Corn Rice Oats

What is Malt?
Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air. Malting grains develops the amylaze enzymes required to modify the grain's starches into sugars, including the monosaccharide glucose, the disaccharide maltose, the trisaccharide maltotriose, and higher sugars called maltodextrines. It also develops other enzymes, such as proteases, which break down the proteins in the grain into forms that can be used by yeast. Malt also contains small amounts of other sugars, such as sucrose and fructose, which are not products of starch modification but were already in the grain.

What is Modification?
The quality of starches in a grain is variable with the strain of grain used and its growing conditions. "Modification" refers specifically to the extent to which starch molecules in the grain consist of simple chains of starch molecules versus branched chains; a fully modified grain contains only simple-chain starch molecules. A grain that is not fully modified requires mashing in multiple steps rather than at simply one temperature as the starches must be de-branched before amylase can work on them. One indicator of the degree of modification of a grain is that grain's Nitrogen ratio; that is, the amount of soluble Nitrogen in a grain vs. the total amount of Nitrogen. This number is also referred to as the "Kolbach Index" and a malt with a Kolbach index between 36% and 42% is considered a malt that is highly modified and suitable for single infusion mashing (see chart). Maltsters use the length of the acrospire vs. the length of the grain to determine when the appropriate degree of modification has been reached before drying or kilning.

Nitrogen content = Protein content
The nitrogen content of a grain refers to the mass fraction of the grain that is made up of protein, and is usually expressed as a percentage; this fraction is further refined by distinguishing what fraction of the protein is water-soluble, also usually expressed as a percentage; 40% is typical for most beermaking grains. Generally, brewers favor lower-nitrogen grains, while distillers favor high-nitrogen grains. The presence of high-mass proteins causes "chill haze", a cloudy visual quality to the beer. However, this is mostly a cosmetic desire dating from the mass production of glassware for presenting serving beverages; traditional styles such as sahti, saison and bière de garde, as well as several Belgian styles, make no special effort to create a clear product. The quantity of high-mass proteins can be reduced during the mash by making use of a protease rest which we will discuss later on.
In Britain, preferred brewers' grains are often obtained from winter harvests and grown in low-nitrogen soil; in central Europe, no special changes are made for the grain-growing conditions and multi-step decoction mashing is favored instead to degrade the proteins to acceptable levels.

Distillers, by contrast, are not as constrained by the amount of protein in their mash as the non-volatile nature of proteins means that none will be included in the final distilled product. Therefore, distillers seek out higher-nitrogen grains in order to ensure a more efficiently-made product; higher-protein grains generally have more diastatic power which we will discuss here in a minute.

What is Drying and Kilning?
Drying – Once the maltster determines that the malted grains, now called green malt, are sufficiently modified, they are moved to a kiln and carefully dried to about 4% moisture content. Drying takes place over a period of twenty-four to thirty-six hours at a temperature of 122° to 158°. For some types of malt this is the end of the process. These are called base malts. Note: certain base malts are lightly kilned (ie: Vienna, Munich), but this degrades their enzymatic potential (see chart).

Kilning – After drying some grains are heated in kilns at higher temperatures and for longer periods of time. This extended kilning gives these malts the unique colors and flavors. Lower temperature and shorter duration kilning results in light colored grains with more subtle flavor characteristics. Longer kilning times and higher temperatures result in dark colored malts with more intense flavors. Two chemical reactions are involved in the development of these colors and flavors, caramelization and Maillard reactions. Caramelization is the decomposition of sugar at high heat. It results in sweet flavors like toffee, molasses, and raisin. The Maillard reaction is the darkening that results from
interactions of amino acids and sugars. It is the same reaction that makes toasted bread brown or creates grill marks on meat. Maillard reactions result in the bready, toasty, and biscuity flavors associated with baking. Malts that have undergone kilning or roasting are called specialty malts.

Base Malts
What are they?
Beers are differentiated from each other by their color, flavor, alcohol content, hopping and many other factors. But they all have one thing in common before they become an individual beer style — fermentable sugars that form the “base” of the beer. This base of fermentable sugars comes from the starches in the base malts. They’re called base malts precisely because they form the base of the beer. They typically comprise anywhere from 60 to 100 percent of the grist.

The base malt has several functions in a recipe. The first is to provide the base of fermentable sugars for the beer. The majority of the alcohol content of the beer is established by adjusting the amount of base malt in a recipe — the more malt, the more alcohol. The second function is to provide the base flavor profile for the beer. This is most important in beers that don’t use a lot of specialty malts in addition to the base malt. In other words, if you use a lot of flavorful specialty malts, their flavor will tend to mask the flavor of the base malt. Conversely, if there are little to no specialty malts in the recipe, the flavor of the base malt is more important. Last, the base malt provides enzymes to convert its starches into sugars. It also provides extra enzymes to convert adjuncts (like corn or flaked barley) that lack enough enzymes of their own to do the job.

Common Base Malts:

2-row Malts 6-row Malt Pale Malt Wheat Malt
Pilsen Malts Munich Malts Vienna Malt Maris Otter
UK Pale Golden Promise Rye Malt

Enzymes in Base Malts:
Enzymatic Rests
Optimal rest temperatures for major mashing enzymes
Temp °F Enzyme Breaks down
104.0-113.0 °F β-Glucanase β-Glucan
122.0-129.2 °F Protease Protein
143.6-152.6 °F β-Amylase Starch
150.8-161.6 °F α-Amylase Starch
In step-infusion and decoction mashing, the mash is heated to different temperatures at which specific enzymes work optimally. The table at right shows the optimal temperature ranges for the enzymes brewers pay the most attention to and what material those enzymes break down. There is some contention in the brewing industry as to just what the optimal temperature is for these enzymes, as it is often very dependent on the pH of the mash, and its thickness. A thicker mash acts as a buffer for the enzymes. Once a step is passed, the enzymes active in that step are denatured by the increasing heat and become permanently inactive. The time spent transitioning between rests is preferably as short as necessary; however, if the temperature is raised more than 1 °C per minute, enzymes may be prematurely denatured. Note: Acid rest utilizing Phytase enzyme at 95°F will not be covered today.

β-Glucanase Rest
β-glucan is a general term for polysaccharides, such as cellulose, made up of chains of glucose molecules connected by beta glycosidic bonds, as opposed to alpha glycosidic bonds in starch. These are a major constituent of the cell wall of plants, and make up a large part of the bran in grains. A β-glucanase rest done at 104°F is practiced in order to break down cell walls and make starches more available, thus raising the extraction efficiency. This rest can also reduces the amount of β-glucan in the final beer for those looking to reduce this complex sugar due to gluten intolerance or Celiac Disease.

A Rest just for Hefs?
Mashing at 110 °F is said to aid in the hydrolysis of ferulic acid. The yeast use ferulic acid to produce 4-vinyl guaiacol, which is the phenolic (clove-like) flavor compound that is so often sought in this style.

Protease Rest
Protein degradation via a proteolytic rest done between 122°F and 129°F plays many roles: production of free-amino nitrogen (FAN) for yeast nutrition, freeing of small proteins from larger proteins for foam stability in the finished product, and reduction of haze-causing proteins for easier filtration and increased beer clarity. In all-malt beers, the malt already provides enough protein for good head retention, and the brewer needs to worry more about more FAN being produced than the yeast can metabolize, leading to off flavors. The haze causing proteins are also more prevalent in all-malt beers, and the brewer must strike a balance between breaking down these proteins and limiting FAN production.

Amylase Rests
The amylase rests are responsible for the production of free fermentable and nonfermentable sugar from starch in a mash. Starch is an enormous molecule made up of branching chains of glucose molecules.

By mashing between 144°F and 152°F, β-amylase breaks down these chains from the end molecules forming links of two glucose molecules, i.e. maltose. β-amylase cannot break down the branch points, although some help is found here through low α-amylase activity and enzymes such as dextrinase. The maltose will be the yeast's main food source during fermentation. During this rest starches also cluster together forming visible bodies in the mash. This clustering eases the lautering process.

The α-amylase rest between 150°F and 161°F is also known as the saccharification rest, because during this rest the α-amylase breaks down the starches from the inside, and starts cutting off links of glucose one to four glucose molecules in length. The longer glucose chains, sometimes called dextrins or maltodextrins, along with the remaining branched chains, give body and fullness to the beer.

Because of the closeness in temperatures of peak activity of α-amylase and β-amylase, the two rests are often performed at once, with the time and temperature of the rest determining the ratio of fermentable to nonfermentable sugars in the wort and hence the final sweetness of the fermented drink; a hotter rest gives a fuller-bodied, sweeter beer as α-amylase produces more unfermentable sugars. (see Mash Chart)

Diastatic Power
Diastatic power is a measure of how much starch-converting enzyme any given malt contains for use during the amylase rests. When you make the jump from extract brewing to all-grain, you’ll want to make sure you have enough diastatic power in your grist to convert the starches to sugar. If you don’t, your mash will fall short of its intended starting gravity and the residual starches will cause clarity problems as well as a food source for bacteria. Fortunately, modern base malts usually have plenty of diastatic power. You will really only need to worry about a shortage of diastatic power when your recipe has a large amount of grains without any diastatic power.

Diastatic power (DP) is measured in degrees Lintner. As a general rule of thumb, you want to make sure your mash averages 70 Linter or above. With most recipes, this isn’t too hard to do. Also note that heat above 161°F can destroy the diastatic power in the malt. If this is your first mashing attempt where your temperature targeting could be a bit off, I suggest you keep the diastatic power above 100 to be safe.

Note that some malts have a lot of diastatic power. 6-row malt is the highest. Others don’t have any, such as crystal malts, and anything that falls into the category of “unmalted” (as is the case with flaked grains). Specialty malts such as Munich malt are at the low end of the range. Since most recipes use a lot of diastatic-containing malt and only small amount of non-diastatic, the total diastatic power is seldom a problem. The good news is that this is very easy to calculate before you mash in. Just multiply the diastatic power of the base malts by the number of pounds of that grain and divide by the total pounds of grain in your recipe.

Take a typical Pale Ale for example. If you use 6 pounds of 2-row malt (DP = 140) and 1 pounds of crystal malt (DP = 0) your average is 120 and you should have nothing to worry about. This mash will work fine.

Another example, take a Witbier recipe, which has 3.5 lb Pilsner malt (DP = 130), 1.5 lb 6-row malt (DP = 180) and 5 lb of unmalted wheat (DP = 0). Note that in this example, fully half of the grain had no diastatic power. This averaged out to 72 Lintner. Again, no worries. However if you dropped the 6-row and use 5 pounds of Pilsner malt your average would only be 65 Lintner. Here the amylase enzymes should still get the job done, but your mash duration may have to be extended for full starch conversion. Now if you substituted Munich malt (DP = 40) for the Pilsner your average would only be 20 Lintner and chances are you are in for serious starch conversion trouble regardless of what your brewing software might predict for this grist. What to do? In such cases you will need to add additional amylase enzymes in the form of a product such as Termamyl Liquid Endo-Alpha Amylase.

Specialty Malts
While many factors create a beer’s overall flavor, the specialty malts you choose for your brew may have the biggest impact on how it is perceived.

Most all-grain beer recipes consist of 60 to 90 percent two- or six-row malt. The rest of the grain bill consists of one or more specialty malts. Your choice of specialty malts will have a dramatic impact on the flavor, mouthfeel and color of the beer. Specialty malts range in flavor from the light and sweet Crystal Malts to the robust flavor and color packed Roasted Malts.

Crystal (Caramel) Malts
Crystal malts are malts that the maltster mashes in the kernel. In other words the maltster takes green malt without crushing it and hydrates it. He then heats the water-malt mixture to a mash temperature of 140° to 160° F. This causes the malt enzymes to degrade the starch in the kernel, thus effectively mashing each individual kernel. The maltster then dries the mashed malt kernels at a given temperature from 180° to 350° F. This causes the sugars to crystallize. It also causes the sugars and nitrogen-based compounds (mostly amino acids and proteins) to combine to form melanoidins (brown to red color agents). The higher the drying temperature, the darker the color will be. Caramelization is the formation of brown color from the rearrangement of sugar molecules without the help of nitrogen-based molecules. Caramelization aslo occurs during this malting process which is why these malts are interchangeably referred to as caramel malts.
Crystal malts range in color (measured in degrees Lovibond) anywhere from 1.5°L (Carapils) to 220°L (Special B) and can be used from 5% to 25% of the grist in a given recipe.

Roasted Malts
Most of these dark, flavorful malts undergo the same traditional “mashed in the kernel process” as crystal malts do (the exception being Roasted Barley), but they are then slowly drum-roasted to varying gradations between 300 and over 450 degrees Fahrenheit, giving each its characteristic taste, color, and aroma. The spectrum of roasted flavors depending on degree of roast.
The dark, flavorful malts range in color anywhere from 200°L (Pale Chocolate) to 550°L (Midnight Wheat) and are generally kept from 3% to 10% of the grist in a given recipe.
The trick in brewing with roasted grains lies in extracting their smooth, bitter, roasted notes without summoning undesirable astringency and harshness. When subjected to persistent, high temperatures and/or excessive amounts of sparge water, the husk surrounding barley grains can be responsible for mouth-puckering off-flavors. While de-husked roasted grains, such as Carafa, are blissful additions that circumvent this problem, the husked versions are far more common, but when handled correctly pose no off-flavor risk. As no temperature-specific enzymatic activity is necessary to convert the sugars they do not need to be added to the tun right from the get-go. In fact, they do not need to be added to the tun at all. There are several mashing techniques can be used to extract their flavors.

Hot steeping
Place your crushed roasted grains in a grain bag and steep in a separate kettle for 30 minutes between 150 and 160 degrees Fahrenheit at a water-to-grist ratio of 2 quarts per 1 pound. The most positive aspects of this method are that it can be performed concurrently with your main mash, the brew bag makes your grist easy to remove, and you can add your steeped liquid to your brew kettle in precisely controlled amounts and whenever you want during the boil. The longer you boil your roasted grain liquid, the more prominent flavors, colors, and aromas you develop.
Cold Steeping
Place your crushed roasted grains in a grain bag and steep overnight at room temperature in a separate kettle of cold water at a water-to-grist ratio of 2 quarts per 1 pound. On brewing day, simply remove your grain bag and add your liquid to your main kettle for boiling. By steeping your grains cold for an extended period of time, you avoid astringent or harsh flavors derived from hot steeping, while retaining the ability to add your roasted grain liquid to your boil at your leisure.
Adding Roasted Grains at Mash-Out
Whether you use direct heat or you infuse your mash with hot water additions to raise the temperature, simply add your quantity of roasted grains during your mash-out phase and lauter and sparge as usual. This is by far my favorite method to brew with roasted grains even though it requires the most care. Adding your roasted grains at mash-out requires no additional equipment compared to the other two processes. By adding your roasted grains at mash-out and proceeding with your regular lautering and sparging programs you also minimize the time your roasted grains are exposed to high . This method adds clean, developed, roasted flavor without much additional hassle.
Huskless Grains
Wheat Rye (Carafa)

Rice hulls anyone?
Unmalted Grains and other Non-Grain Options
Flaked Barley Flaked Wheat Flaked Oats Flaked Corn Wheat
Potatoes Sweet Potatoes Yams Pumpkin Squash
Generally no cereal mash required. Rice hulls recommended!!
Corn/Hominy Rice
Cereal mash required to gelatinize starches and make them available to the enzymes present in the mash

How to do a cereal mash
To do a cereal mash, combine your "cereal" — whether, it's corn or rice, an unmalted grain or other starchy food — with about 10% six-row barley malt or 15% two-row barley malt. The malt should be crushed and — if your cereal is another grain — crush that too. Slice, dice or otherwise reduce the size of other starchy foods to small enough pieces so that they will hydrate quickly. You can go higher on the barley percentage if you want, up to around 30% if you wish.

Add water and begin heating the cereal mash. Shoot for a thin gruel-like consistency. Some foods will take on water as they cook, so don't be afraid to add water as you go if the cereal mash gets too gooey.

Bring the cereal mash to the high end of the starch conversion range, around 158 °F and hold for 5 minutes. The barley malt in the mix will attempt to convert any stray starches at this point, but the bulk of the starches will be converted in the main mash.

After the five-minute rest, bring the cereal mash to a boil. This step is to gelatinize the starches and to obtain better extraction. You will need to stir nearly constantly as it heats and boils to prevent scorching. Boil the mash for 30 minutes. When the cereal mash is done, stir it into your main mash. At this point, the starches in the cereal mash will be exposed to the amylase enzymes in the main mash and degraded.














Reference Citations and Follow Up Research Resources:

http://byo.com/mead/item/710-grain-on-the-brain

http://www.beercolor.com/malt_descriptions.htm

http://www.brewingwithbriess.com/Assets ... alysis.pdf

http://www.beeradvocate.com/beer/101/malts/

http://braukaiser.com/wiki/index.php/Braukaiser.com

http://en.wikipedia.org/wiki/Mash_ingredients

http://www.highgravitybrew.com/productc ... -p3099.htm

http://brewwiki.com/index.php/Main_Page

http://www.aperfectpint.net/Brewing%20Grains.pdf

http://www.whatsbrewingsupply.com/Grainlist.pdf

http://www.beertools.com/html/ingredien ... iew=grains

https://byo.com/soda-pop/item/1395-spec ... sted-malts

http://www.brew-monkey.com/brewschool/maltguide.php

https://byo.com/mashing/item/442-cereal ... techniques

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