Cork is an impermeable buoyant material. It is the phellem layer of bark tissue which is harvested for commercial use primarily from Quercus suber, which is native to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance. Because of its impermeable, buoyant, elastic, and fire retardant properties, it is used in a variety of products, the most common of which is wine stoppers.
An aroma compound, also known as an odorant, aroma, fragrance or flavoring, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently volatile for transmission via the air to the olfactory system in the upper part of the nose. As examples, various fragrant fruits have diverse aroma compounds, particularly strawberries which are commercially cultivated to have appealing aromas, and contain several hundred aroma compounds.
Brettanomyces is a non-spore forming genus of yeast in the family Saccharomycetaceae, and is often colloquially referred to as "Brett". The genus name Dekkera is used interchangeably with Brettanomyces, as it describes the teleomorph or spore forming form of the yeast, but is considered deprecated under the one fungus, one name change. The cellular morphology of the yeast can vary from ovoid to long "sausage" shaped cells. The yeast is acidogenic, and when grown on glucose rich media under aerobic conditions, produces large amounts of acetic acid. Brettanomyces is important to both the brewing and wine industries due to the sensory compounds it produces.
Malolactic conversion is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and common for some white grape varieties such as Chardonnay, where it can impart a "buttery" flavor from diacetyl, a byproduct of the reaction.
Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether with a methyl and phenyl group attached. Anisole is a standard reagent of both practical and pedagogical value.
2,4,6-Trichloroanisole (TCA) is an organic compound with the formula CH3OC6H2Cl3. It is the symmetric isomer of trichloroanisole. It is a colorless solid.
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.
Wine corks are a stopper used to seal wine bottles. They are typically made from cork, though synthetic materials can be used. Common alternative wine closures include screw caps and glass stoppers. 68 percent of all cork is produced for wine bottle stoppers.
Alternative wine closures are substitute closures used in the wine industry for sealing wine bottles in place of traditional cork closures. The emergence of these alternatives has grown in response to quality control efforts by winemakers to protect against "cork taint" caused by the presence of the chemical trichloroanisole (TCA).
2,4,6-Trichlorophenol, also known as TCP, phenaclor, Dowicide 2S, Dowcide 2S, omal, is a chlorinated phenol that has been used as a fungicide, herbicide, insecticide, antiseptic, defoliant, and glue preservative. It is a clear to yellowish crystalline solid with a strong, phenolic odor. It decomposes on heating to produce toxic and corrosive fumes including hydrogen chloride and chlorine.
The aging of wine is potentially able to improve the quality of wine. This distinguishes wine from most other consumable goods. While wine is perishable and capable of deteriorating, complex chemical reactions involving a wine's sugars, acids and phenolic compounds can alter the aroma, color, mouthfeel and taste of the wine in a way that may be more pleasing to the taster. The ability of a wine to age is influenced by many factors including grape variety, vintage, viticultural practices, wine region and winemaking style. The condition that the wine is kept in after bottling can also influence how well a wine ages and may require significant time and financial investment. The quality of an aged wine varies significantly bottle-by-bottle, depending on the conditions under which it was stored, and the condition of the bottle and cork, and thus it is said that rather than good old vintages, there are good old bottles. There is a significant mystique around the aging of wine, as its chemistry was not understood for a long time, and old wines are often sold for extraordinary prices. However, the vast majority of wine is not aged, and even wine that is aged is rarely aged for long; it is estimated that 90% of wine is meant to be consumed within a year of production, and 99% of wine within 5 years.
This glossary of winemaking terms lists some of terms and definitions involved in making wine, fruit wine, and mead.
In winemaking, clarification and stabilization are the processes by which insoluble matter suspended in the wine is removed before bottling. This matter may include dead yeast cells (lees), bacteria, tartrates, proteins, pectins, various tannins and other phenolic compounds, as well as pieces of grape skin, pulp, stems and gums. Clarification and stabilization may involve fining, filtration, centrifugation, flotation, refrigeration, pasteurization, and/or barrel maturation and racking.
Storage of wine is an important consideration for wine that is being kept for long-term aging. While most wine is consumed within 24 hours of purchase, fine wines are often set aside for long-term storage. Wine is one of the few commodities that can improve in flavour and value with age, but it can also rapidly deteriorate if kept in inadequate conditions.
Organoleptic properties are the aspects of food, water or other substances as apprehended via the senses—including taste, sight, smell, and touch.
A screw cap is a metal, normally aluminium, cap that screws onto threads on the neck of a wine bottle, generally with a metal skirt down the neck to resemble the traditional wine capsule ("foil"). A layer of plastic, cork, rubber, or other soft material is used as wad to make a seal with the mouth of the bottle. Its use as an alternative to cork for sealing wine bottles is gaining increasing support. In markets such as Australia and New Zealand screw caps on bottles have overtaken cork to become the most common means of sealing bottles.
2,4,6-Tribromoanisole (TBA) is a chemical compound that is a brominated derivative of anisole. It is one of the chemicals responsible for cork taint.
Nomacorc now known as Vinventions, is a company producing engineered synthetic corks for wine bottles. Nomacorc closures are co-extruded to manage the oxygen transfer rate for wine, reducing 2,4,6-trichloroanisole (TCA), more commonly known as cork taint.
Adsorbable organic halides (AOX) is a measure of the organic halogen load at a sampling site such as soil from a land fill, water, or sewage waste. The procedure measures chlorine, bromine, and iodine as equivalent halogens, but does not measure fluorine levels in the sample.
Smoke taint is a broad term for a set of smoke imparted compounds found in affected wines, constituting a wine fault. Increasing incidences of smoke tainted wines are an important issue, given the recent occurrences of wildfires or bushfires in wine grape producing regions during the growing seasons. Examples of wildfires resulting in smoke tainted wines include the fires in South Africa in late 2017, October 2017 Northern California wildfires, the 2019–20 Australian bushfire season, and the 2020 Glass Fire in Northern California.
