Wine glass
A wine glass is a type of glass that is used to drink and taste wine. Most wine glasses are stemware, i.e. goblets composed of three parts: the bowl, stem, and foot. Shapes. The effect of glass shape on the taste of wine has not been demonstrated decisively by any scientific study and remains a matter of debate. One study suggests that the shape of the glass is important, as it concentrates the flavour and aroma (or bouquet) to emphasize the varietal's characteristic. One common belief is that the shape of the glass directs the wine itself  into the best area of the mouth for the varietal despite flavour being perceived by olfaction in the upper nasal cavity, not the mouth. The importance of wine glass shape could also be based on false ideas about the arrangement of different taste buds on the tongue, such as the thoroughly discredited tongue map. Most wine glasses are stemware, that is they are goblets composed of three parts: the bowl, stem, and foot. In some designs, the opening of the glass is narrower than the widest part of the bowl (to concentrate the aroma), others are more conical. In addition , "stemless" wine glasses (tumblers) are available in a variety of sizes and shapes. The latter are typically used more casually than their traditional counterparts, as they negate the benefits of using stemmed wine glasses. Some common types of wine glasses are described below. Red wine glasses. Glasses for red wine are characterized by their rounder, wider bowl, which increases the rate of oxidation. As oxygen from the air chemically interacts with the wine, flavor and aroma are believed to be subtly altered. This process of oxidation is generally considered more compatible with red wines, whose complex flavours are said to  be smoothed out after being exposed to air. Red wine glasses can have particular styles of their own, such as White wine glasses. White wine glasses vary enormously in size and shape, from the delicately tapered Champagne flute, to the wide and shallow glasses used to drink Chardonnay. Different shaped glasses are used to accentuate the unique characteristics of different styles of wine. Wide-mouthed glasses function similarly to red wine glasses discussed above, promoting rapid oxidation which alters the flavor of the wine. White wines which are best served slightly oxidized are generally full-flavored wines, such as oaked  chardonnay. For lighter, fresher styles of white wine, oxidation is less desirable as it is seen to mask the delicate nuances of the wine. To preserve a crisp, clean flavored wine, many white wine glasses will have a smaller mouth, which reduces surface area and in turn, the rate of oxidization. In the case of sparkling wine, such as Champagne or Asti, an even smaller mouth is used to keep the wine sparkling longer in the glass. Champagne flutes. Champagne flutes are characterised by a long stem with a tall, narrow bowl on top. The shape is designed to keep  sparkling wine desirable during its consumption. Just as with wine glasses, the flute is designed to be held by the stem to help prevent the heat from the hand from warming the liquid inside. The bowl itself is designed in a manner to help retain the signature carbonation in the beverage. This is achieved by reducing the surface area at the opening of the bowl. Additionally, the flute design adds to the aesthetic appeal of champagne, allowing the bubbles to travel further due to the narrow design, giving a more pleasant visual appeal. Sherry glass. A sherry glass or schooner  is drinkware generally used for serving aromatic alcoholic beverages, such as sherry, port, aperitifs, and liqueurs, and layered shooters. The "copita", with its aroma-enhancing narrow taper, is a type of sherry glass. Boccalino. A boccalino is a mug used in Ticino, Switzerland, to drink local wine (Merlot or similar). It has a volume of approximately 200 ml. Use. Some authors recommend one holds the glass by the stem, to avoid warming the wine and smudging the bowl. Materials. High quality wine glasses once were made of lead glass, which has a higher index of refraction and is heavier than  ordinary glass, but health concerns regarding the ingestion of lead resulted in their being replaced by lead-free glass. Wine glasses, with the exception of the hock glass, are generally not coloured or frosted as doing so would diminish appreciation of the wine's colour. There used to be an ISO standard (ISO/PAS IWA 8:2009) for glass clarity and freedom from lead and other heavy metals, but it was withdrawn. Some producers of high-end wine glasses such as Schott Zwiesel have pioneered methods of infusing titanium into the glass to increase its durability and reduce the likelihood of  the glass breaking. Decoration. In the 18th Century, glass makers would draw spiral patterns in the stem as they made the glass. If they used air bubbles it was called an airtwist; if they used threads, either white or coloured, it would be called opaque twist. ISO wine tasting glass. The International Organization for Standardization has a specification (ISO 3591:1977) for a wine-tasting glass. It consists of a cup (an "elongated egg") supported on a stem resting on a base. The glass must be lead crystal (9% lead). Its dimensions give it a total volume between 210 mL and  225 mL, they are defined as follows: The opening is narrower than the convex part so as to concentrate the bouquet. The capacity is approximately 215 ml, but it is intended to take a 50 ml pour. Some glasses of a similar shape, but with different capacities, may be loosely referred to as ISO glasses, but they form no part of the ISO specification. Measures in licensed premises. In the UK there has been a steady trend away from serving wine in the standard size of 125 ml, towards the larger size of 250 ml, even though, since 1 October  2010, alcohol retailers have been obliged by law to offer customers the choice of a smaller measure. A code of practice, introduced in April 2010 as an extension to the Licensing Act 2003, contains five mandatory conditions for the sale of alcohol, including an obligation for the licensee to make the customer aware that small measures are available. Capacity measure. As a supplemental unit of apothecary measure, the wineglass (also known as "wineglassful", pl. "wineglassesful", or "cyathus vinarius" in pharmaceutical Latin) was defined as of a pint, (2 fluid ounces by US measure, or 2 fluid ounces by imperial measure ). An older version (before c. 1800) was 1 fluid ounces. These units bear little relation to the capacity of most contemporary wineglasses, or to the ancient Roman cyathus.