Liquid Malt Extract (Lme) is concentrated, unfermented brewery wort, a viscous syrup used in brewing—especially homebrewing—as well as in the food industry. LME is a common ingredient in baked goods, confectionery, breakfast cereals, malt beverages, dairy products, and condiments. It is often used as a caramel substitute. Just as wort is produced in many different colors and flavors, so is LME. It may be hop flavored or not. The production of LME through milling, mashing, mash separation, and wort boiling is very similar to that of conventional beer wort. See boiling, lautering, mash, and milling. Depending on the desired color and flavor, the grist bill for LME is either made up of just one malt type or is a varied mixture of pale and specialty malts. See, for instance, black malt, caramel malts, and crystal malt. Mash separation is ideally achieved using a mash filter rather than a traditional lauter tun because wort can be recovered at a notably higher gravity, which reduces the time, energy, and cost during the concentration phase. Once the wort has been boiled, it is usually concentrated further by evaporation until it is made up of roughly 70% to 80% solids. See malt syrup. If it is reduced further, to a powdered from, it is called dried malt extract or spray malt. See dried malt extract. Finally, the LME is aseptically packaged, usually in a metal can or a plastic Jerry can, for distribution.

Because LME is simply unfermented, concentrated postboil wort, its content is proportionally identical to wort (except, of course, for the water content) and it has all of the normal wort trace elements, including zinc, iron, manganese, potassium, calcium, copper, and magnesium, as well as vitamins and lipids. LME, therefore, can enable yeast growth and sustain its metabolism just as well as any normal wort. Most of the fermentable sugar in LME is in the form of maltose (about 60% to 70%). For brewing, LME needs to be diluted with hot water to the required gravity, heated to sterilize, and then cooled and fermented like regular wort. LME is available in a large range of formulations, especially for homebrewers, who can choose among many beer style-specific varieties, including wheat, Munich, amber, pils, porter, and stout. Many homebrewers also mix various packaged LMEs for even greater variability. Some LMEs contain additions of diastatic enzymes to allow for the use of unmalted starch adjuncts in the brewing process. See adjuncts, amylases, diastatic power, and enzymes. Such LMEs, however, must not be heated above 74°C (approximately 165°F) before any desired starch conversion because the heat would denature the necessary enzymes.

Commercial brewers, too, have found many uses for LMEs. Small start-up microbreweries and brewpubs, for instance, may defer the cost purchasing of a mash and lauter tun by brewing with LMEs. Likewise, breweries may find it more efficient to mash and lauter only one wort, usually pale, and blend different LMEs with it in the brew kettle to produce several different beer styles. One special application is the addition of a specially formulated maltodextrin LME, which is rich in unfermentable sugars, to a wort intended for a low-alcohol beers. The unfermentable sugars give the resulting beer a fuller body and enhance its mouthfeel.

See also dextrins.