Acids in wineThe acids in wine are an important component in both winemaking and the finished product of wine. They are present in both grapes and wine, having direct influences on the color, balance and taste of the wine as well as the growth and vitality of yeast during fermentation and protecting the wine from bacteria. The measure of the amount of acidity in wine is known as the “titratable acidity” or “total acidity”, which refers to the test that yields the total of all acids present, while strength of acidity is measured according to pH, with most wines having a pH between 2.
Pressing (wine)In winemaking, pressing is the process where juice is extracted from the grapes with the aid of a wine-press, by hand, or even by the weight of the grape berries and clusters. Historically, intact grape clusters were trodden by feet but in most wineries today the grapes are sent through a crusher/destemmer, which removes the individual grape berries from the stems and breaks the skins, releasing some juice, prior to being pressed.
Asti wineAsti (also known as Asti Spumante) is a sparkling white Italian wine that is produced throughout southeastern Piedmont but is particularly focused around the towns of Asti and Alba. Since 1993 the wine has been classified as a Denominazione di Origine Controllata e Garantita (DOCG) and as of 2004 was Italy's largest producing appellation. On an average vintage more than ten times as much Asti is produced in Piedmont than the more well-known Piedmontese red wine Barolo.
Malolactic fermentationMalolactic conversion (also known as malolactic fermentation or MLF) 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.
WineWine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are major factors in different styles of wine. These differences result from the complex interactions between the biochemical development of the grape, the reactions involved in fermentation, the grape's growing environment (terroir), and the wine production process.
Wine faultA 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 (e.g., an off-odor) might arise from more than one wine fault. Wine faults may result from poor winemaking practices or storage conditions that lead to wine spoilage.
Fortified wineFortified wine is a wine to which a distilled spirit, usually brandy, has been added. In the course of some centuries, winemakers have developed many different styles of fortified wine, including port, sherry, madeira, Marsala, Commandaria wine, and the aromatised wine vermouth. One reason for fortifying wine was to preserve it, since ethanol is also a natural antiseptic. Even though other preservation methods now exist, fortification continues to be used because the process can add distinct flavors to the finished product.
Yeast assimilable nitrogenYeast assimilable nitrogen or YAN is the combination of free amino nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for a yeast, e.g. the wine yeast Saccharomyces cerevisiae, to use during fermentation. Outside of the fermentable sugars glucose and fructose, nitrogen is the most important nutrient needed to carry out a successful fermentation that doesn't end prior to the intended point of dryness or sees the development of off-odors and related wine faults.
Madeira wineMadeira is a fortified wine made on the Portuguese Madeira Islands, off the coast of Africa. Madeira is produced in a variety of styles ranging from dry wines which can be consumed on their own, as an apéritif, to sweet wines usually consumed with dessert. Cheaper cooking versions are often flavoured with salt and pepper for use in cooking, but these are not fit for consumption as a beverage.