Names | |
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Preferred IUPAC name 2-Methoxy-3-(propan-2-yl)pyrazine | |
Other names 2-Isopropyl-3-methoxypyrazine | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.042.946 |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C8H12N2O | |
Molar mass | 152.19 g/mol |
Hazards | |
GHS labelling: [1] | |
Warning | |
H315, H319, H335 | |
P302+P352, P305+P351+P338 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Isopropyl methoxypyrazine (IPMP) is a methoxypyrazine, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the Asian lady beetle or by the actinomycete Streptomyces sp. [2] It can be detected by human taste at concentrations of as low as 2 nanograms per litre. [3]
The odor of IPMP tends to be undesirable in the case of certain wines. [4]
Cabernet Sauvignon has high levels of methoxypyrazines. [5] [6] Two methoxypyrazine compounds, 3-isobutyl-2-methoxypyrazine (IBMP) and 3-isopropyl-2-methoxypyrazine, are considered to be important determinants of green flavours in Sauvignon blanc wines. [7]
IPMP is also an important flavour compound in coffee and is responsible for causing an off-taste called "potato taste" in East African coffee. [8] The insects Antestiopsis are also implicated in causing the taste. [9]
Merlot is a dark blue–colored wine grape variety that is used as both a blending grape and for varietal wines. The name Merlot is thought to be a diminutive of merle, the French name for the blackbird, probably a reference to the color of the grape. Its softness and "fleshiness," combined with its earlier ripening, make Merlot a popular grape for blending with the sterner, later-ripening Cabernet Sauvignon, which tends to be higher in tannin.
Cabernet Sauvignon is one of the world's most widely recognized red wine grape varieties. It is grown in nearly every major wine producing country among a diverse spectrum of climates from Australia and British Columbia, Canada to Lebanon's Beqaa Valley. Cabernet Sauvignon became internationally recognized through its prominence in Bordeaux wines, where it is often blended with Merlot and Cabernet Franc. From France and Spain, the grape spread across Europe and to the New World where it found new homes in places like California's Napa Valley, New Zealand's Hawke's Bay, South Africa's Stellenbosch region, Australia's Margaret River, McLaren Vale and Coonawarra regions, and Chile's Maipo Valley and Colchagua. For most of the 20th century, it was the world's most widely planted premium red wine grape until it was surpassed by Merlot in the 1990s. However, by 2015, Cabernet Sauvignon had once again become the most widely planted wine grape, with a total of 341,000 hectares (3,410 km2) under vine worldwide.
Sauvignon blanc is a green-skinned grape variety that originates from the city of Bordeaux in France. The grape most likely gets its name from the French words sauvage ("wild") and blanc ("white") due to its early origins as an indigenous grape in South West France. It is possibly a descendant of Savagnin. Sauvignon blanc is planted in many of the world's wine regions, producing a crisp, dry, and refreshing white varietal wine. The grape is also a component of the famous dessert wines from Sauternes and Barsac. Sauvignon blanc is widely cultivated in France, Chile, Romania, Canada, Australia, New Zealand, South Africa, Bulgaria, the states of Oregon, Washington, and California in the US. Some New World Sauvignon blancs, particularly from California, may also be called "Fumé Blanc", a marketing term coined by Robert Mondavi in reference to Pouilly-Fumé.
White wine is a wine that is fermented without skin contact. The colour can be straw-yellow, yellow-green, or yellow-gold. It is produced by the alcoholic fermentation of the non-coloured pulp of grapes, which may have a skin of any colour. White wine has existed for at least 4,000 years.
Browning is the process of food turning brown due to the chemical reactions that take place within. The process of browning is one of the chemical reactions that take place in food chemistry and represents an interesting research topic regarding health, nutrition, and food technology. Though there are many different ways food chemically changes over time, browning in particular falls into two main categories: enzymatic versus non-enzymatic browning processes.
Sémillon is a golden-skinned grape used to make dry and sweet white wines, mostly in France and Australia. Its thin skin and susceptibility to botrytis make it dominate the sweet wine region Sauternes AOC and Barsac AOC.
A coffee bean is a seed from the Coffea plant and the source for coffee. It is the pip inside the red or purple fruit. This fruit is often referred to as a coffee cherry, and like the cherry, it is a fruit with a pip. Even though the coffee beans are not technically beans, they are referred to as such because of their resemblance to true beans. The fruits most commonly contain two stones with their flat sides together. A small percentage of cherries contain a single seed, instead of the usual two, called a "peaberry". The peaberry occurs only between 10% and 15% of the time, and it is a fairly common belief that they have more flavour than normal coffee beans. Like Brazil nuts and white rice, coffee beans consist mostly of endosperm.
Sancerre is a French wine Appellation d'origine contrôlée (AOC) for wine produced in the area of Sancerre in the eastern part of the Loire valley, southeast of Orléans. Almost all of the appellation lies on the left bank of the Loire, opposite Pouilly-Fumé. It is well regarded for and primarily associated with Sauvignon blanc. Some Pinot noir is also grown, accounting for around 20% of the region's production, making mostly light red wines under the designation of Sancerre Rouge. A rosé style from Pinot noir is also produced in a style similar to Beaujolais, which is produced from the Gamay grape.
Italian wine is produced in every region of Italy. Italy is the world's largest wine producer, as well as the country with the widest variety of indigenous grapevine in the world, with an area of 702,000 hectares under vineyard cultivation, and contributing a 2013–2017 annual average of 48.3 million hl of wine. In 2018 Italy accounted for 19 per cent of global production, ahead of France and Spain. Italian wine is both exported around the world and popular domestically among Italians, who consume an average of 42 litres per capita, ranking fifth in world wine consumption.
A wine fault is a sensory-associated (organoleptic) characteristic of a wine that is unpleasant, and may include elements of taste, smell, or appearance, elements that may arise from a "chemical or a microbial origin", where particular sensory experiences might arise from more than one wine fault. Wine faults may result from poor winemaking practices or storage conditions that lead to wine spoilage.
South African wine has a history dating back to 1659 with the first bottle being produced in Cape Town by its founder and governor Jan van Riebeeck. Access to international markets led to new investment in the South African wine market. Production is concentrated around Cape Town and almost exclusively located within the Western Cape province, with major vineyard and production centres at Constantia, Paarl, Stellenbosch and Worcester.
Methoxypyrazines are a class of chemical compounds that produce odors. The odors tend to be undesirable, as in the case of certain wines, or as defensive chemicals used by insects such as Harmonia axyridis which produces isopropyl methoxy pyrazine (IPMP). They have also been identified as additives in cigarette manufacture. Detection thresholds are very low, typically near 2 parts per trillion (1 ng/L).
3-Mercapto-3-methylbutan-1-ol, also known as MMB, is a common odorant found in food and cat urine. The aromas ascribed to MMB include catty, roasty, broth-like, meaty, and savory, or similar to cooked leeks.
Ann C. Noble is a sensory chemist and retired professor from the University of California, Davis. During her time at the UC Davis Department of Viticulture and Enology, Noble invented the "Aroma Wheel" which is credited with enhancing the public understanding of wine tasting and terminology. At the time of her hiring at UC Davis in 1974, Noble was the first woman hired as a faculty member of the Viticulture department. Noble retired from Davis in 2002 and in 2003 was named Emeritus Professor of Enology. Since retirement she has participated as a judge in the San Francisco Chronicle Wine Competition.
Alkylpyrazines are chemical compounds based on pyrazine with different substitution patterns. Some alkylpyrazines are naturally occurring highly aromatic substances which often have a very low odor threshold and contribute to the taste and aroma of various foods including cocoa, baked goods, coffee and wines. Alkylpyrazines are also formed during the cooking of some foods via Maillard reactions.
The aromas of wine are more diverse than its flavours. The human tongue is limited to the primary tastes perceived by taste receptors on the tongue – sourness, bitterness, saltiness, sweetness and savouriness. The wide array of fruit, earthy, leathery, floral, herbal, mineral, and woodsy flavour present in wine are derived from aroma notes sensed by the olfactory bulb. In wine tasting, wine is sometimes smelled before taking a sip in order to identify some components of the wine that may be present. Different terms are used to describe what is being smelled. The most basic term is aroma which generally refers to a "pleasant" smell as opposed to odour which refers to an unpleasant smell or possible wine fault. The term aroma may be further distinguished from bouquet which generally refers to the smells that arise from the chemical reactions of fermentation and aging of the wine.
Antestiopsis is a genus of shield bug in the tribe Antestiini: commonly known as antestia or variegated coffee bugs. Several species in eastern Africa are pests of coffee plants, giving the coffee beans a distinctive 'potato taste'.
Merlot blanc is a white French wine grape variety that came from a natural crossing of the Bordeaux wine grape Merlot and the Cognac grape Folle blanche. The grape is distinct from Merlot gris which is a pink-skinned color mutation of the red wine grape Merlot and is sometimes used in vin gris and rosé wines. Plantings of Merlot blanc were first discovered in 1891 but cuttings of the vine have not been widely propagated and the variety is very rare. It is not used to make the sweet White Zinfandel-style wine White Merlot that is made by some California wine producers. Those wines are made from a saignee of red Merlot wine.
Cabernet blanc is a white German and Swiss wine grape variety that is a crossing of the French wine grape Cabernet Sauvignon and Regent. The grape was bred by Swiss grape breeder Valentin Blattner in 1991. Cabernet blanc has strong resistance to most grape disease including botrytis bunch rot, downy and powdery mildew and tends to produce loose clusters of small, thick-skinned grape berries which can hang on the vine late into the harvest season to produce dessert wines. Today the grape is found primarily in the Palatinate wine region of Germany with some experimental plantings in Spain and the Netherlands. In France, in the Languedoc, Domaine La Colombette is heavily investing in PIWI grapes. Amongst others the Cabernet Blanc in their cuvée "Au Creux du Nid", is gaining wide acclaim.
3-Isobutyl-2-methoxypyrazine is a methoxypyrazine that is very similar to isopropyl methoxy pyrazine except that the alkyl side-group contains an isobutyl group attached to the carbon alpha to the methoxy sidegroup instead of an isopropyl side-group at that same carbon position.