The short answer is: Mostly malted barley
In our last post, we wrote about what malt actually is. For this post, we’ll discuss how it’s made and a bit about what it does. Malt is responsible for providing the sugar that Brewer’s yeast use
Malt is also responsible for the charachteristics in beer most easily described as the flavors of“baked goods”. Think of bread, all kinds. Think of caramel sweetness, roasted coffee, Chocolate, biscuits and toast. There are many more but those homey, familiar flavors are a good start to the galaxy of contributions which malt makes to finished beer.
Lately, it’s been an underappreciated contributing ingredient to the flavor of beer, outside of huge “imperial” styles. That’s all well and good but, in my opinion, malt is best used and appreciated in more subtle, delicate applications. The soft, clean, bready flavors of a perfectly made German Helles bring the flavors of the malt right down to the field it was grown in . The round, caramel and biscuit notes in a 5% abv Scottish ale, like our ten penny bit are a great representation of the subtelty of the maltsters craft. Of course you can taste the malt in a 10% behemoth, but I prefer a high-five to a punch in the face any day. Maybe it’s just me.
Malt gives beer more than flavor and aroma, because the kilning process used by maltsters also has a great deal to do with the color of the finished beer. Just as highly kilned coffee makes for a robust, darker brew, highly kilned malts, even when used as a small percentage of the overall grain bill (the part of the beer recipe which has to do with cereal grains), can provide similar roasted flavors and colors. So, how does a brewer know which malt to use in order to brew a beer with the flavor and color he or she desires?
Malt is categorized in a few ways in order to indicate to a brewer what it should be, do and provide, more or less. The specific type of Barley (working name and quality grade) from which the malt was produced matters a great deal, but is only really considered in modern craft breweries in a few cases, and mostly only for the “base malt” used in a given beer. Base Malt is used for between around 70%-100% of the grain bill of most beers; even dark black monsters like imperial stout. In the cases of Pale and Pilsner malt, the maltster takes great care to treat the grain very gently throughout the process, creating a malt which is not only delicate in flavor, but also contains all of the natural enzymes and available sugars the brewer will need to make a perfect environment for his or her yeast to work.
The process of malting is commonly broken down into 4 steps: Steeping/germination, Withering, Curing and, in the case of malts intended to add color to beer, Roasting.
The beginning of the malting process – Steeping and Germination – is one whereby grain is soaked and allowed to begin growth under moist, warm conditions in order to allow each kernel to begin the natural conversion of starch into sugar. That conversion process is stopped when the maltster deems that the ratio of sugar to starch in the grain is sufficient to its intended use. Brewers malt, for example, is less converted than distillers malt, so that the remaining starch in the grain will help to give the resulting beer a fuller mouthfeel and more robust character. Since distilled beverages do not require those qualities from malt, the malt distillers use is allowed to convert as completely as possible. Once the malt has converted to the maltsters satisfaction, it heads to the kiln for the next step of the process, called withering or drying. The kiln is essentially a large room where temperature and humidity (ventilation) can be strictly controlled.
In most cases, Withering takes the moisture content of the germinated seed down from 45% to about 4.5%. Usually this is done at 90 to 115 derees farenheit and takes about 2 days. At the end of this stage, the rootles and acrospire which have grown out of the kernel as part of germination are shaken off, and the kernel looks remarkably similar to its former self before the germination process began. Withering is not always included as a seperate step in descriptions of the malting process, as not all malt must be withered. For example, in the case of Munich, Vienna, and particularly Crystal/Cara malt, ventilation and temperature are tightly controlled so that a moist malt can be “stewed” in the next steps. We’ll cover those types more in the sections below.
The third step, Curing, takes place at higher temperatures than withering. Generally the curing phase takes about 5 hours. Ventilation is more or less high, and temperature is generally the most controlled variable. For example Munich, Vienna and Aromatic are cured at much higher temperatures (210 to 240 F) in order to achieve their depth of character. Pils or Pale Malts are cured at 175 to 200F in order to preserve the flavor of the “pure malt”.
At this point, malts which require no further “roasting” (Pilsner and Pale, among many others) are finished and can be packaged for sale to brewers.
The next step is for potential “high carbon” (chocolate, black patent, etc.) malts, which give notes of coffee, chocolate and other “dark” flavors, is Roasting. Roasting is most commonly performed in a large, rotating drum. Think about a huge clothes dyer that gets really hot and you’ve got it, more or less. Spray nozzles are installed in the drum to quickly regulate temperature and as a fire prevention system. Unmalted barley can skip the previous costly steps and is used to make black and roasted barley in this step.
So-called “toasting” is also carried out in the Roaster, but uses lower Temperature for varying amounts of time. Biscuit and Victory, among other malt types, are “toasted” malts and are famnous for their assertive, deep character.
“Crystal Malts”: As mentioned above Crystal malts are unique and differ from other forms of malt in both the way that they are made in the malthouse and used in the brewhouse. Crystal malts can be made in a kiln or in a special roasting drum. In either case, the withering step is abbrevieated or abandoned entirely so that moist (green) malt can be put directly into the kiln or roaster from the germination tanks or withering step. In the case of these special malts, the moisture in the kiln or drum is kept very high with absolutely no ventilation. Frequent water additions are sprayed to keep the moisture high during this step. The temperature is raised to 140 – 160F for 30 to 40 minutes. Then the temperature is raised to 305F and normal ventilation is resumed for 1 to 2 hours, depending on how much caramelization is desired (i.e. depending on whether 10L (light) crystal or 90L (darker) crystal is being made). This results in a glassy interior and a malt rich in Dextrin, which is an unfermentable sugar that lends sweetness and some body to the finished beer.
If prepared in the kiln, further drying of the Cara malt will be necessary [DeClerck, p242]. Crystal malts are finished after drying, and no roasting is performed on these Dextrin and color rich malts.
Enzymatic and Diastatic power are considerations which maltsers and brewers must be concious of. If, for example, a brewer wanted to use a great deal of biscuit malt in his or her brew, they would need to be aware that biscuit malt has no ability to further “convert” starch into sugar in the mash, so aid might be needed in the form of raw barley or a high diastaic power Pils or Pale malt. Aromatic malt, on the other hand, can convert itself after the malting process, though not as well as a base malt might.
More on that and how different malts play into recipe writing in another post…