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Isohumulone
Isohumulones are chemical compounds that contribute to the bitter taste of beer and are in the class of compounds known as iso-alpha acids. They are found in hops. Beer The bitterness of beer is measured according to the International Bitterness Units scale, with one IBU corresponding to one part-per-million of isohumulone. When beer is exposed to light, these compounds can decompose in a reaction catalyzed by riboflavin to generate free-radical species by the homolytic cleavage of the exocyclic carbon-carbon bond. The cleaved acyl side-chain radical then decomposes further, expelling carbon monoxide and generating 1,1-dimethylallyl radical. This radical can finally react with sulfur-containing amino acids, such as cysteine, to create 3-methylbut-2-ene-1-thiol, a thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beer Chemistry
The chemical compounds in beer give it a distinctive taste, smell and appearance. The majority of compounds in beer come from the metabolic activities of plants and yeast and so are covered by the fields of biochemistry and organic chemistry. The main exception is that beer contains over 90% water and the mineral ions in the water (hardness) can have a significant effect upon the taste. Four main ingredients Four main ingredients are used for making beer in the process of brewing: carbohydrates (from malt), hops, yeast, and water. Carbohydrates (from malt) The carbohydrate source is an essential part of the beer because unicellular yeast organisms convert carbohydrates into energy to live. Yeast metabolize the carbohydrate source to form a number of compounds including ethanol. The process of brewing beer starts with malting and mashing, which breaks down the long carbohydrates in the barley grain into more simple sugars. This is important because yeast can only metabo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humulone
Humulone (α-lupulic acid), a vinylogous type of organic acid, is a bitter-tasting chemical compound found in the resin of mature hops (''Humulus lupulus''). Humulone is a prevalent member of the class of compounds known as alpha acids, which collectively give hopped beer its characteristic bitter flavor. Chemistry In terms of structure, humulone is a phloroglucinol derivative with three isoprenoid side-chains. Two side-chains are prenyl groups and one is an isovaleryl group. The acidity of the ring enol moieties that give rise to its designation as an acid lie in their vinylogous relationship with the ring and side chain carbonyl functional groups. Isohumulone During the brewing process, humulone degrades to ''cis-'' and ''trans-''isohumulone. These “alpha acids” survive the boiling process, although numerous oxidized derivatives are produced. The iso-alpha acids are significantly more soluble than humulone at the pH levels typically present in the brewing process. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hops
Hops are the flowers (also called seed cones or strobiles) of the hop plant ''Humulus lupulus'', a member of the Cannabaceae family of flowering plants. They are used primarily as a bittering, flavouring, and stability agent in beer, to which, in addition to bitterness, they impart floral, fruity, or citrus flavours and aromas. Hops are also used for various purposes in other beverages and herbal medicine. The hops plants have separate female and male plants, and only female plants are used for commercial production. The hop plant is a vigorous, climbing, herbaceous perennial, usually trained to grow up strings in a field called a hopfield, hop garden (in the South of England), or hop yard (in the West Country and United States) when grown commercially. Many different varieties of hops are grown by farmers around the world, with different types used for particular styles of beer. The first documented use of hops in beer is from the 9th century, though Hildegard of Bingen, 30 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compounds
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beer
Beer is one of the oldest and the most widely consumed type of alcoholic drink in the world, and the third most popular drink overall after water and tea. It is produced by the brewing and fermentation of starches, mainly derived from cereal grains—most commonly from malted barley, though wheat, maize (corn), rice, and oats are also used. During the brewing process, fermentation of the starch sugars in the wort produces ethanol and carbonation in the resulting beer.Barth, Roger. ''The Chemistry of Beer: The Science in the Suds'', Wiley 2013: . Most modern beer is brewed with hops, which add bitterness and other flavours and act as a natural preservative and stabilizing agent. Other flavouring agents such as gruit, herbs, or fruits may be included or used instead of hops. In commercial brewing, the natural carbonation effect is often removed during processing and replaced with forced carbonation. Some of humanity's earliest known writings refer to the production and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iso-alpha Acid
Alpha acids (α acids) are a class of chemical compounds primarily of importance to the production of beer. They are found in the resin glands of the flowers of the hop plant and are the source of hop bitterness. Alpha acids may be isomerized to form iso-alpha acids by the application of heat in solution. Iso-alpha acids (iso-α-acids) are typically produced in beer from the addition of hops to the boiling wort. The degree of isomerization and the amount of bitter flavor produced by the addition of hops is highly dependent on the length of time the hops are boiled. Longer boil times will result in isomerization of more alpha acids and thus increased bitterness. Common alpha acids include humulone, adhumulone, cohumulone, posthumulone, and prehumulone. The most common iso-α-acids are ''cis''- and ''trans''-isohumulone. Bittering The alpha acid "rating" on hops indicates the amount of alpha acid as a percentage of total weight of the hop. Hops with a higher alpha ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Bitterness Units Scale
When drinking beer, there are many factors to be considered. Principal among them are bitterness, the variety of flavours present in the beverage and their intensity, alcohol content, and colour. Standards for those characteristics allow a more objective and uniform determination to be made on the overall qualities of any beer. Colour "Degrees Lovibond" or "°L" scale is a measure of the colour of a substance, usually beer, whiskey, or sugar solutions. The determination of the degrees Lovibond takes place by comparing the colour of the substance to a series of amber to brown glass slides, usually by a colorimeter. The scale was devised by Joseph Williams Lovibond. The Standard Reference Method (SRM) and European Brewery Convention (EBC) methods have largely replaced it, with the SRM giving results approximately equal to the °L. The Standard Reference Method or SRM is a system modern brewers use to measure colour intensity, roughly darkness, of a beer or wort. The method i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parts-per Notation
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, ), parts-per-billion (ppb, ), parts-per-trillion (ppt, ) and parts-per-quadrillion (ppq, ). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous. Overview Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL. Therefore, it is common to equat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalyze
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some stag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riboflavin
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in energy metabolism, cellular respiration, and antibody production, as well as normal growth and development. The coenzymes are also required for the metabolism of niacin, vitamin B6, and folate. Riboflavin is prescribed to treat corneal thinning, and taken orally, may reduce the incidence of migraine headaches in adults. Riboflavin deficiency is rare and is usually accompanied by deficiencies of other vitamins and nutrients. It may be prevented or treated by oral supplements or by injections. As a water-soluble vitamin, any riboflavin consumed in excess of nutritional requirements is not stored; it is either not absorbed or is absorbed and quickly excreted in urine, causing the urine to have a bright yellow tint. Natural sources of rib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiol
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in the hydroxyl () group of an alcohol), and the word is a blend of "''thio-''" with "alcohol". Many thiols have strong odors resembling that of garlic or rotten eggs. Thiols are used as odorants to assist in the detection of natural gas (which in pure form is odorless), and the "smell of natural gas" is due to the smell of the thiol used as the odorant. Thiols are sometimes referred to as mercaptans () or mercapto compounds, a term introduced in 1832 by William Christopher Zeise and is derived from the Latin ('capturing mercury')''Oxford American Dictionaries'' (Mac OS X Leopard). because the thiolate group () bonds very strong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beer Bottle
A beer bottle is a bottle designed as a container for beer. Such designs vary greatly in size and shape, but the glass commonly is brown or green to reduce spoilage from light, especially ultraviolet. The most widely established alternatives to glass containers for beer in retail sales are beverage cans and aluminium bottles; for larger volumes kegs are in common use. Bottling lines Bottling lines are production lines that fill beer into bottles on a large scale. The process is typically as follows: # Filling a bottle in a filling machine (''filler'') typically involves drawing beer from a holding tank # Capping the bottle, labeling it # Packing the bottles into cases or cartons Many smaller breweries send their bulk beer to large facilities for contract bottling—though some will bottle by hand. The first step in bottling beer is ''depalletising'', where the empty bottles are removed from the original packaging delivered from the manufacturer, so that individual bottles ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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