°Lintner or degrees Lintner is a unit used to measure the ability of a

malt Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as "malting". Malted grain is used to make beer, whisky, malted milk, malt vinegar, ...

to reduce

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

, that is, its diastatic power. Degrees Lintner is an intensive unit, not an extensive one; it is independent of the quantity of malt used. While the measurement is applicable to any

amylase An amylase () is an enzyme that catalysis, catalyses the hydrolysis of starch (Latin ') into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large ...

, in general it refers to the combined α-amylase and β-amylase used in

brewing Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and #Fermenting, fermenting the resulting sweet liquid with Yeast#Beer, yeast. It may be done in a brewery ...

. The term is also generalized to diastatic

malt extract Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as " malting". Malted grain is used to make beer, whisky, malted milk, malt vinegar ...

s and separately prepared brewing enzymes. The abbreviation °L is official, but in brewing applications it may conflict with °L used for degrees Lovibond. JECFA, the Joint FAO/WHO Expert Committee on Food Additives, defines the degree Lintner as follows: :''A malt has a diastatic power of 100 °L if 0.1 cc of a clear 5% infusion of the malt, acting on 100cc of a 2%

solution at 20°C for one

hour An hour (symbol: h; also abbreviated hr) is a unit of time historically reckoned as of a day and defined contemporarily as exactly 3,600 seconds ( SI). There are 60 minutes in an hour, and 24 hours in a day. The hour was initially establis ...

, produces sufficient reducing sugars to reduce completely 5cc of Fehling's solution.'' Note that the amylases used in brewing reach their peak efficiencies around 66 °C. One can convert this definition to the number of international enzyme units (IU, enzyme activity that produces 1 μmole of product per minute) per gram of grain, for example. Maltose, the main sugar produced in mashing, is a disaccharide of glucose with one reducing equivalent (one reactive aldehyde group). One maltose will reduce two Cu²⁺ in the Fehling reaction. The concentration of Cu²⁺ in Fehling’s solution is 0.14 M, which is capable of oxidizing 0.070 M maltose. 5 mL of Fehling’s solution can oxidize 0.070 M x 0.005 L = 0.00035 moles of maltose. A 100 °L malt extract produces 0.00035 mol maltose in 60 min, or 5.8 μmol/min, or 5.8 IU of enzyme activity in 0.1 mL of a 5 g/100 mL (5%) infusion. The 0.1 mL of this infusion is equivalent to 0.005 g of malt. Therefore, 5.8 IU/0.005 g of malt = 1160 IU/gram of malt. 100 °L is equivalent to 1160 IU per gram of malt (or 526,176 IU per pound). This value is useful if alternatives to Fehling's reaction are being used to determine the amylase activity. Evaluation of a malt or extract is usually done by the manufacturer rather than by the end user; as a rule of thumb, the total grain bill of a mash should have a diastatic power of at least 40 °L in order to guarantee efficient conversion of all the starches in the mash to sugars. The most active

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

malts currently available have a diastatic activity of 110 - 160 °Lintner (385 - 520 °WK). In Europe, diastatic activity is often stated in Windisch–Kolbach units (°WK). These are related approximately to °Lintner by: :

^\circ\mbox = \frac

^\circ\mbox = \left ( 3.5 \times ^\circ\mbox{Lintner} \right ) - 16

References

External links

"Malt Carbohydrase", JECFA, 1971.
Gives definitions and procedures for measuring diastatic activity. Brewing Units of catalytic activity