What is Malt?
When one thinks of beer, one should think of the four primary ingredients: water, malt, hops, and yeast.
But what is malt?
Malt, or malted grain, is the sugar source that yeast converts into carbon dioxide and ethanol. Cereal grains, such as barley, wheat, oats, and rye, are germinated, which allows the proteins in the endosperm to be broken down and various enzymes are converted or developed. This process is also known as modification.
Malts that are highly modified mean the β-glucans and proteins in the endosperm of the grain kernels are broken down and the amylase enzymes are produced. Malts that are less modified or under modified retain more β-glucans and proteins, which can be addressed in the mash.
There are several types of malt used in brewing. Additionally, unmalted grains can also be employed in recipes. Here, we’ll discuss base malts, specialty malts, and the unmalted grains typically used in brewing beer.
This article was originally published at brewthelookingglass.com.
Terminology: Conversion, Extract Potential, and Color
Conversion – Diastatic Power, °L
In order for the starches amylose and amylopectin to be broken down into smaller sugars or saccharides, amylase enzymes need to be present in the mash. The ability of a particular malt to do this task (i.e. the total activity of malt enzymes that break down, or hydrolyze, starch) is measured by a value called diastatic power.
This value is measured in °Lintner, °L (not to be confused with °Lovibond, also °L, which we’ll discuss later) and high levels of DP (>30 °L) in the mash are needed to convert the starches into sugar.
Extract Potential – What’s your Target SG?
When building recipes, a brewer needs to know how much grain to add to reach a target ABV. Working backwards, the brewer needs to know how much sugar she can extract from the grain. A malt’s “extract potential” is a metric expressed as specific gravity that results from 1 lb of malt in 1 gallon of water.
For example, 1 lb of sucrose in 1 gallon of water will produce a specific gravity of 1.04621. On a malt’s certificate of analysis (CoA), you’ll find an extract value, sometimes shown as extract dry basis fine grind, DBFG. This is usually expressed as a percentage. For example, for Weyermann’s pilsner malt, the specification sheet (which the CoA uses to show how to report results and what the acceptable measured values should be) shows the minimum extract (dry substance) should be at least 80.5%. To find out the extract potential in terms of specific gravity, we’ll use the following equation:
Extract Potential (SG) = 1 + (Dry Basis Fine Grind/100) x 0.04621.
So, for the pilsner malt, at the minimum value acceptable per the specification, the minimum extract potential would be:
1 + (85/100) x 0.04621 = 1.03928 or 1.039.
Another way of saying this is a brewer can expect a minimum 39 points per pound per gallon (ppg) for this malt, assuming 100% efficiency of the brewer’s brew system:
ppg = (SG – 1) x 1000 x efficiency
Color – °L (Lovibond), SRM, or EBC
The color of malt can be presented in three different units: °Lovibond (°L), Standard Reference Method (SRM), or European Brewers Convention (EBC). Determining degrees Lovibond is performed by using a colorimeter to compare the color of a substance to a series of amber or brown glass slides. Both the SRM and EBC methods for determining color are spectrophotometric methods.
In the United States, the color of malt is typically represented in °L, which will be what we report below.
Base Malts
We use base malts to lay the foundation of our beer recipes. They account for 60% to 100% of the entire grain bill, or grist, by weight. These grains provide fermentable sugars (e.g., glucose, maltose, maltotriose, etc.) and free amino nitrogen (FAN) that are used by yeast during fermentation.
In beer brewing, barley is typically the grain of choice, with many of the base malts being malted barley that has been kilned to various degrees of color. There are two types of barley used; 2-row and 6-row. Two-row barley has larger and more consistently sized kernels than 6-row. Malt from 6-row barley is only used in the United States for brewing. Elsewhere, it is used for livestock feed.
From here, we’ll discuss different malts made from 2-row barley:
2-row or Pale Malt
Two-row, also known as “pale malt”, is a common base for ale recipes. Light in color, around 2 °L, this malt provides a very light grain, bread crust, or cracker flavor.
Pale Ale Malt
Not to be confused with “pale malt”, pale ale malt is kilned at a higher temperature than pale malt. These malts are typically 2-3 °L. This provides a nutty and biscuity (digestive cookie) flavor or toast-like character.
There are a few common “brands” of pale ale malt in the UK: Maris Otter and Golden Promise. Maris Otter is a winter barley variety. Golden Promise is a spring barley variety.
Pilsner Malt
Pilsner malt (1-2 °L) has a soft sweetness, providing a light bready or cracker flavor.
Mild Malt
Mild malt is a lightly toasted malt (3 °L) that imparts a nutty flavor. It is typically used in milds, porters, and stouts.
Munich Malt
Often found in light and dark versions, Munich malt is a highly kilned base malt that imparts a range of aromas including caramel, honey, and bread, and a malty flavor. It provides a light copper hue in beer, due to the 5–10 °L color of the malt.
Vienna Malt
Vienna malt is roasted further than pilsner or pale malt, which means it provides a lower amount of diastatic power. It has enough diastatic power to convert its own starches but be careful when adding a lot of adjuncts in your recipes.
At 3 to 3.5 °L, Vienna malt provides a nice golden to amber color to beer. The flavor is sweet, rich malt with a toasty character.
What Makes You So Special – Specialty Malts
Base malts offer a nice foundation for a beer recipe, however, specialty malts are an incredibly diverse and useful set of tools available to the artistic brewer.
Acidulated Malt
Acidulated malt or acid malt is a pale-colored malt that has been subjected to lactic acid fermentation prior to kilning. The resulting lactic acid is used to reduce the mash pH. In order to drop the pH of the mash 0.1 pH units, 1% of acidulated malt by weight of the total grain bill (e.g., 50 g in a 5 kg batch).
Typically, acidulated malt is used up to 5% of the total grist in ales and lagers, depending on the residual alkalinity of the water used in brewing. Notably, acidulated malt is widely used in Germany (or for those following the Reinheitsgebot) to manage pH.
Amber Malt
Amber malt offers a warm, toasty, biscuit flavor to beer. Coming in around 20 °L, it can impart a brown hue to beer.
Amber malt can be used up to 20% of the total grist.
Aromatic Malt
Aromatic malt, also known as aroma malt, is a highly kilned malt (25 °L) that imparts rich, sweet, and toasted flavors.
Aromatic malt can be used up to 50% of the total grist.
Biscuit Malt
Biscuit malt (~25 °L) provides a cracker and bread-like aroma and imparts a light brown color.
Biscuit malt can be used up to 15% of the total grist.
Black Malt
Black malt is kilned at very high temperatures, resulting in a malt that is around 500 °L. When used in small amounts, it can impart a red color to the beer. However, a little goes a long way—too much will impart an astringent, dry-burnt bitterness that is rather unpleasant to most palates.
Note: Use carefully. Black malt can be used up to 5% of the grist.
Caramel or Crystal Malts
Caramel or crystal malts come in a broad range of colors, which leads to a broad range of flavors. The lightest caramel malts impart a light caramel, biscuit, or honey flavor. The darker the caramel malt, the more pronounced flavors like raisins, dates, and burnt sugars.
Most caramel/crystal malts can be used from 5% to 25% of the total grist. However, certain maltsters have recommended maximums outside of this range. For instance, CaraMunich can be used up to 40%.
Under this category, I’ll also mention Special B, which is a dark Belgian specialty malt that imparts raisin, cherry, plum, and burnt sugar flavors. Special B can be used up to 5% of the grist.
Chocolate Malt
Chocolate malts are kilned at a high temperature to obtain a chocolate color (400+ °L). They can impart a nutty, toasted aroma and flavors. These can be used to adjust the color of beer to provide an amber or red hue when used in small amounts.
I’ll add the Carafa malts from Weyermann here. They come in standard and de-husked (Special) varieties. The de-husked varieties can eliminate some of the astringency typically produced by darker roasted malts with their husks intact.
Chocolate malts are typically used as up to 5% of the total grist.
Dextrin Malts
Dextrin malts add dextrins, or unfermentable sugars, to the wort and are used to help boost body and mouthfeel. They can also be used to boost head retention, although the verdict is still out as to the extent to which dextrin malts are foam stability positive or negative.
Dextrin malts are typically used between 5% to 15% of the grist, however, malts like Carafoam can be used up to 40%. Check with the particular maltster to see their recommendations.
Oat Malt
Oat malt imparts a silky smooth mouthfeel to beer. Lightly kilned, oat malts are 1–2 °L.
Oat malt is typically used between 5% and 20% of the total grist.
Rye Malt
Rye malt (2-4 °L) imparts a spicy aroma and flavor. It can be added to “dry out” a beer and can add a creamy head. Rye malt has a high concentration of β-glucans, so the addition of rice hulls or performing a protein rest (as described here) can be useful.
Typically rye malt can be used up to 30% of the total grist.
Wheat Malt
Now, whether or not wheat malt is considered a true base malt is up for debate, but one could make a beer with 100% wheat malt. One downside of using 100% wheat malt is that wheat contains a lot of protein and β-glucans, which tend to make mashes and the resulting sparge rather sticky. The addition of rice hulls or performing a protein rest can be useful.
Wheat malt comes in two varieties: white and red. White wheat malt is made from a winter variety, whereas red wheat malt is made from a spring variety.
Wheat malt can boost head or foam stability in beers.
Adjuncts – Why use them?
Sometimes specialty grains and base malts get a brewer most of the way to their dreamed creation, but adjuncts can be the finishing touch that the brewer is seeking.
Flaked (Unmalted) Grains
Flaked grains are usually pre-cooked or pregelatinized to make the starches readily soluble, which eliminates the need to perform a separate cereal mash prior to the addition of the unmalted grains to the mash.
Barley
Flaked barley offers a slightly grainy flavor and can be used to boost body and head retention. It is typically used up to 25% of the total grist.
Corn/Maize
Flaked corn or maize add fermentable sugars and promote a dry finishing beer. It can be used up to 40% of the total grist.
Oats
Flaked oats impart a silky and creamy mouthfeel. It is typically used between 5% and 20% of the total grist.
Rice
Flaked rice adds fermentable sugars and promotes a crisp finishing beer. It can be used up to 40% of the total grist.
Rye
Flaked rye imparts a crisp, spicy character. It is typically used between 5% and 10% of the total grist, however, it can be used up to 40% for rye beer styles.
Wheat
Flaked wheat can boost head retention and mouthfeel, as well as impart more turbidity or haze to a beer. It is typically used between 5% and 10% of the total grist.
Other adjuncts
Roasted Barley
Roasted barley (~500 °L) provides chocolate and coffee flavors. Like black malt, it can be used to adjust the hue of beers to amber or red.
Roasted barley can be used up to 15% of the total grist.
Sugars
Corn Sugar (Dextrose)
Dextrose, also known as glucose, is used as an adjunct to boost ABV without adding any body. It is also commonly used as priming sugar when bottling beer.
Sucrose
Sucrose, a disaccharide composed of glucose and fructose, is an inexpensive alternative to dextrose. You’ll find sucrose as table sugar, beet sugar, or cane sugar.
Belgian candi sugar
Belgian candi sugar is a caramelized invert sugar typically produced from beet sugar. It is usually supplied in one of three forms: soft, syrup, or rock. Like caramel malts, Belgian candi sugar comes in a range of colors, which provide a range of flavors, from no flavor (clear) to toffee, molasses, honey, raisin/dates, and dark treacle (dark).
Belgian candi sugars are typically used at up to 20% of the total grist.
Honey and Other Syrups
Honey, maple syrup, and agave syrup are common adjuncts used in brewing. They are almost completely fermentable and can add subtle flavors and aromas to beer.
Lactose
Lactose is an unfermentable sugar that increases the residual sweetness and body of a beer. It is typically used up to 10% of the total grist.
Produce
Fruits and culinary vegetables (such as pumpkins) can be used as adjuncts in beer. Typically added for flavor, it should be noted that not all fruits will come across equally in the finished beer. Fruits like raspberries and passionfruit can be bold, whereas blueberries and strawberries can easily be hidden by other strong flavors.
Conclusions
We have discussed some common base malts, specialty malts, and adjuncts used in brewing. What are your favorites to use in your brew?