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 enzymes required to modify the grain's starches into sugars, including monosaccharides such as glucose or fructose, and disaccharides, such as sucrose or maltose. It also develops other enzymes, such as proteases, which break down the proteins in the grain into forms which can be used by yeast.
Malted grain is used to make beer, whisky, malted shakes, malt vinegar, confections such as Maltesers and Whoppers, flavored drinks such as Horlicks, Ovaltine and Milo, and some baked goods, such as malt loaf. Malted grain which has been ground into a coarse meal is known as "sweet meal". Various cereals are malted, though barley is the most common. A high-protein form of malted barley is often a label-listed ingredient in blended flours typically used in the manufacture of yeast breads and other baked goods.
The term "malt" refers to several products of the process: the grains to which this process has been applied, for example malted barley; the sugar, heavy in maltose, derived from such grains, such as the baker's malt used in various cereals; or a product based on malted milk, similar to a malted milkshake (i.e., "malts").
Malting is the process of converting barley into malt, for use in brewing or distilling, and takes place in a maltings, sometimes called a malthouse, or a malting floor. The sprouted barley is kiln-dried by spreading it on a perforated wooden floor. Smoke, coming from an oasting fireplace (via smoke channels) is then used to heat the wooden floor and the sprouted grains. The temperature is usually around 55 °C (131 °F). A typical floor maltings is a long, single-story building with a floor that slopes slightly from one end of the building to the other. Floor maltings began to be phased out in the 1940s in favour of "pneumatic plants". Here, large industrial fans are used to blow air through the germinating grain beds and to pass hot air through the malt being kilned. Like floor maltings, these pneumatic plants are batch processes, but of considerably greater size, typically 100 tonne batches compared with 20 tonne batches for floor malting.
The malting process starts with drying the grains to a moisture content below 14%, and then storing for around six weeks to overcome seed dormancy. When ready, the grain is immersed or "steeped" in water two or three times over two or three days to allow the grain to absorb moisture and to start to sprout. When the grain has a moisture content of around 46%, it is transferred to the malting or germination floor, where it is constantly turned over for around five days while it is air dried. The grain at this point is called "green malt". The green malt is then kiln dried to the desired colour and specification. Malts range in colour from very pale through crystal and amber to chocolate or black malts.
Barley is the most commonly malted grain, in part because of its high diastatic power or enzyme content, though wheat and rye are also used. Also very important is the retention of the grain's husk, even after threshing, unlike the bare seeds of threshed wheat or rye. This protects the growing acrospire (developing plant embryo) from damage during malting, which can easily lead to mould growth. It also allows the mash of converted grain to create a filter bed during lautering (see brewing). Malt is often divided into two categories by brewers: base malts and specialty malts. Base malts have enough diastatic power to convert their own starch and usually that of some amount of starch from unmalted grain, called adjuncts. Specialty malts have little diastatic power; they are used to provide flavor, color, or "body" (viscosity) to the finished beer. Specialty caramel or crystal malts have been subjected to heat treatment to convert their starches to sugars nonenzymatically. Within these categories are a variety of types distinguished largely by the kilning temperature (see mash ingredients). In addition, malts are distinguished by the two major species of barley used for malting, two-row and six-row.
A new encapsulating technology permits the production of malt granules. Malt granules are the dried liquid extract from malt used in the brewing or distilling process.
Malt extract is also known as extract of malt. It is a sweet, treacly substance given to children and adults as a dietary supplement. It was popular in the first half of the twentieth century as a supplement for the children of the British urban working-class, whose diet was often deficient in vitamins and minerals. Children were given cod liver oil for the same reason but it proved so unpalatable that it was combined with extract of malt to produce "Malt and Cod-Liver Oil." It was given as a "strengthening medicine" by Kanga to Roo and Tigger in The House at Pooh Corner.
The 1907 British Pharmaceutical Codex's instructions for making nutritional extract of malt do not include a mash out at the end of extraction, and include the use of lower mash temperatures than is typical with modern beer brewing practices. The Codex indicates that diastatic activity is to be preserved by the use of temperatures not exceeding 55 °C (131 °F).
Malt extract production
Malt extract is frequently used in the brewing of beer. Its production begins by germinating barley grain in a process known as malting. This procedure entails immersing barley in water to encourage the grain to sprout, then drying the barley to halt the progress when the sprouting begins. The drying step stops the sprouting, but the enzymes remain active due to the low temperatures used in base malt production. In one before-and-after comparison, malting decreased barley's extractable starch content by about 7% on a dry matter basis, and turned that portion into various other carbohydrates.
In the next step, brewers use a process called mashing to extract the sugars. Brewers warm cracked malt in temperature-modulated water, activating the enzymes, which cleave more of the malt's remaining starch into various sugars, the largest percentage of which is maltose. Modern beer mashing practices typically include high enough temperatures at mash-out to deactivate remaining enzymes, thus it is no longer diastatic. The liquid produced from this, wort, is then concentrated by using heat or a vacuum procedure to evaporate water from the mixture.
The concentrated wort is called malt extract. Brewers have the option of using a liquid (LME) or dry (DME) form of it. Each has its pros and cons, so the choice is solely dependent on the individual brewer's preferences.
Liquid malt extract is a thick syrup. Some brewers choose to work only with LME, because they feel it works best for the result they wish to achieve. Also, it requires one less processing step, so it is appealing to those who favor the purest form of product available. However, it is very sticky and therefore, messier to work with, has a shorter shelf life, and some feel the results are just as good with DME.
Scientists aim to discover what goes on inside barley grains as they become malted to help plant breeders produce better malting barley for food and beverage products. Agricultural Research Service scientists are interested in specialized enzymes called serine-class proteases that digest beta-amylases, which convert carbohydrates into "simple sugars" during the sprouting process. The enzyme also breaks down stored proteins into their amino acid derivatives. The balance of proteins and carbohydrates broken down by the enzyme affect the malt’s flavor.
- ^ "How to brew manually by John Palmer
- ^ "Quality Factors for Malting, Brewing and other End-uses". Oregon State University. http://oregonstate.edu/instruct/css/330/five/BarleyOverview.htm#BarleyMaltingQuality. Retrieved 2007-04-13.
- ^ What is malting?
- ^ Kirk-Othmer Food and Feed Technology. New York: Wiley-Interscience. 2007. pp. 116–120. ISBN 0-470-17448-X. http://books.google.com/books?id=f--1V1ftgtsC&pg=PT116&lpg=PT116#v=onepage&q&f=false. Retrieved 2010 July 7.
- ^ Horace Kephart (1922). Our southern highlanders (eBook ed.). New York: The Macmillan Company. p. 134. http://books.google.com/books?id=vuNBAAAAIAAJ&pg=PA134#v=onepage&q&f=false. Retrieved 2011 April 10. "The sprouted corn is then dried and ground into meal. This sweet meal is then made into a mush with boiling water, and is let stand two or three days."
- ^ Mills, Margaret H.; Claus, Peter J.; Diamond, Sarah (2003). South Asian folklore: an encyclopedia: Afghanistan, Bangladesh, India, Nepal, Pakistan, Sri Lanka. New York: Routledge. p. 5. ISBN 0-415-93919-4. http://books.google.com/books?id=ienxrTPHzzwC&pg=PA5#v=onepage&q&f=false. Retrieved 2011 April 10. "The grain's own conversion of stored starch to sugar while sprouting ("malting") results in a sweet meal, which is then cooked for hours with water, oil, and additional wheat flour."
- ^ Evers, A. D.; Kent, N. (1994). Technology of cereals: an introduction for students of food science and agriculture. New York: Pergamon Press. p. 181. ISBN 0-08-040834-6. http://books.google.com/books?id=wUwHtcqoP0YC&pg=PA181#v=onepage&q&f=false. Retrieved 2010 July 7.
- ^ "How Malt is Made". www.ukmalt.com. http://www.ukmalt.com/howmaltismade/maltmade.asp. Retrieved 2011-03-26.
- ^ Michael Lewis, Tom W. Young. Brewing. Springer, 2002. p. 204. http://books.google.co.uk/books?id=cr9Pv0gefCQC&pg=PA204&dq=pale+malt+chocolate+malt#v=onepage&q=pale%20malt%20chocolate%20malt&f=false. Retrieved 2011-03-26.
- ^ "Wheat and Rye Malt Use in Brewing Beer.". www.beer-brewing.com. http://www.beer-brewing.com/beer-brewing/barley_malts/other_malted_grains.htm. Retrieved 2011-03-26.
- ^ Goldhammer, Ted (2008), The Brewer's Handbook, 2nd ed., Apex, ISBN 0-9675212-3-8, pp. 31 ff.
- ^ "Patent EP1385931 Malt Granules". www.freepatentsonline.com. http://www.www.freepatentsonline.com/EP1385931.html. Retrieved 2009-05-25.
- ^ a b British pharmaceutical codex. Pharmaceutical Society of Great Britain. 1907. pp. 401–404. http://books.google.com/books?id=-GBKAAAAMAAJ&pg=PA401#v=onepage&q&f=false. Retrieved 2011 Mar 28. "The extract is given to children and adults for its nutritive properties. ... Extract of malt is used as a vehicle for the administration of cod-liver oil (see Extractum Malti cum Oleo Morrhuae), ..."
- ^ Joseph La Villa (2010). The Wine, Beer, and Spirits Handbook: A Guide to Styles and Service. John Wiley & Sons, Inc.. p. 347. ISBN 978-0-470-53757-2. http://books.google.com/books?id=LvKJKnP2LvgC&pg=PT347#v=onepage&q&f=false. Retrieved 2011 Mar 30. "The base malt in any brewing process is called pale malt. It is dried at around 122°F (50°C). Specialty malts are made by either heating the barley before it is dry, or by roasting the dried malt."
- ^ a b Stevens, Roger; Dennis E. Briggs; Chris Boulton; Brookes, Peter (2004). Brewing: science and practice. Cambridge: Woodhead. p. 123. ISBN 0-8493-2547-1. http://books.google.com/books?id=zV9bpyykNtMC&pg=PA123#v=onepage&q&f=false. Retrieved 2011 March 29. See Tables 4.15 & 4.16
- ^ "How to Brew - By John Palmer - Mashing Defined". http://www.howtobrew.com/section3/chapter14-1.html. Retrieved 2011 Mar 28.
- ^ "Like Malt? You’ll Love This Malting Barley Research!". USDA Agricultural Research Service. February 2, 2010. http://www.ars.usda.gov/is/AR/archive/feb10/malt0210.htm.
- ^ "Secrets to Superb Malting Barleys Explored by ARS Researchers". USDA Agricultural Research Service. February 3, 2010. http://www.ars.usda.gov/is/pr/2010/100203.htm. Retrieved March 7, 2011.
- D.E. Briggs, Malts and Malting, Kluwer Academic / Plenum Publishers (30 September 1998), ISBN 0412298007
- Christine Clark, The British Malting Industry Since 1830, Hambledon Continuum (1 July 1998), ISBN 1852851708
Wikimedia Foundation. 2010.