Pasteurization
Developed by the famous French scientist Louis Pasteur while investigating the reasons why beer and wine spoil, pasteurization is the process of killing bacteria via heating the fluid then quickly chilling it. Ironically, wines are not commonly pasteurized because bacteria are necessary for wines to properly age. Some simpler wines that are designed to be enjoyed young are occasionally pasteurized.

Pedro Ximenez (peh'-dro hee-meh'-nez)
Produced most commonly in southern Spain, Pedro Ximenez is a grape varietal used to make white wines. The grape's name is the Spanish translation of Peter Siemens, a German who originally introduced this varietal to Spain's wine country. It is used to make Sherry as well as some unpretentious white wines in Spain and other parts of the world, including Australia and Argentina.

Perfume
A wine tasting term referring to a noticeable floral fragrance and flavor in certain wines. Perfume can also be synonymous with aroma, especially when a wine's aroma is favorable.

Petillant (France)
Lightly effervescent; slightly sparkling. Pétillance is found sometimes in wines not meant to sparkle but which are often bottled with some left-over CO2 - German Rieslings, for example. In Germany, the term for petillant is spritzig, while in Italy it is known as frizzante.

Petite Sirah (peh-teet see-rah)
This grape varietal is also known as Durif, after Francois Durif, the Frenchman who developed the grape in the late 19th Century. The result of a chance cross pollination between Syrah and the French grape Peloursin, Petite Sirah is now grown mainly in California, and increasingly in Australia. Make no mistake, there is nothing petite about Petite Sirah, which produces rich, powerful, and very tannic wines. Often best enjoyed within its first 5 years, it can also benefit from extensive bottle aging which can soften its sometimes extreme tannins.

pH
On a scale of zero to fourteen, pH is the standard for measuring the acidity or alkalinity of a substance. The scale's midpoint of seven is neutral. A pH below seven indicates acidity. Table wines measure, ideally, approximately 3.0 to 3.6. Below 3, a wine becomes sharp; it becomes flabby above 3.6. The pH scale measures the concentration of the acid as opposed to the volume of acid. If the pH is too low or too high, the wine won't be well balanced even if the volume of acid is appropriate. Both determine a wine's potential quality. Low pH also hinders the growth of bacteria which is essential in wines if they're going to age well.

Phylloxera (fil-lox'-er-ra)
The most disastrous plague to ever afflict the wine industry resulted from the Phylloxera, a small insect related to aphids. Indigenous to North America, the phylloxera louse survives by consuming the leaves of North American grape vines. Unfortunately, the louse was inadvertently sent to Europe where it discovered the vinifera variety of grape had delicious appendages - the roots. Phylloxera stopped feeding upon leaves and became a root devouring machine. Given that the lice were feeding underground as opposed to on the leaves, the insects were harder to detect and eliminate. The latter part of the 1800s saw this insect ravage the vineyards of Europe and make its way back to wine producing areas in America, where, for the first time, it attacked vinifera and came close to destroying the wine making business before a solution was finally found. Root stock, native to North America and resistant to the tiny louse, was grafted to vinifera vines around the world, and the industry was spared decimation. Today the grafting technique is still used worldwide and as a result phylloxera is mostly controlled. Occasionally a wine maker, thinking perhaps the threat has diminished and that he can save a few bucks by using non-resistant root stock, plants non-resistant root stock with disastrous results. In California in the 1980s and 90s an epidemic of phylloxera occurred in Napa Valley reminding winemakers to be ever vigilant.

Piedmont / Piemonte (peed-mont / p'yay-mon'-tay)
Called Piemonte in Italian, the name Piedmont translates as "foot of the mountains" and appropriately describes a significant area of wine production in Italy lying at the foot of the Alps where the mountains form natural boundaries between Italy, Switzerland and France. The powerful red wines Barolo and Barbaresco are produced here, as are the light sparkling wines Asti Spumante and Moscato d'Asti. Popular grape varietals include Barbera, Nebbiolo, and Moscato.

Pinot Blanc (pee-no blahnc)
A white wine grape related to Pinot Noir that is grown widely in California, Oregon, and the French region of Alsace. Once, this varietal was prolific within Burgundy where it was planted adjacent to Chardonnay. It seems that much of the supposed Pinot Blanc that winemakers took away from Burgundy to be grown elsewhere actually turned out to be Chardonnay. In particular, many Italian growers of "Pinot Blanco" have been pleasantly surprised to discover they have actually been growing the more popular Chardonnay and they've acted quickly to correctly name their wine. Pinot Blanc grapes are now uncommon in Burgundy. Wines made from Pinot Blanc don't typically age as well as Chardonnays, though better versions will benefit from aging and develop honey-like flavors. They're crisper due to high acid levels, and as a result are finding their way into more and more sparkling wines.

Pinot Grigio (pee-no gree-jee-o)
A wine produced in northern Italy from the grape of the same name. The grape is also called Pinot Gris (France) and Rulander (Germany). Most of this popular wine is dry, crisp, and light, and there are a number of appellations in Italy, such as Colli Orientali and Alto-Adige, that are famous for their excellent Pinot Grigio. There are also some richer, honeyed examples primarily from the Alsace area of France. Grown also in areas of Central and Eastern Europe, Pinot Grigio is not commonly planted in the U.S., except for a small number of growers in California and Oregon.

Pinot Gris (pee-no gree)
See Pinot Grigio. Oregon has recently become well known for its daring, flavorful Pinot Gris.

Pinot Noir (pee-no nwahr)
Native to Burgundy, France, this grape is now planted all over the New World and has become one of the most successful red wine varietals on the planet. California and Oregon produce tremendous examples, and, more recently, New Zealand is fast becoming renowned for fine Pinot Noirs. The grape is also grown for use in many top-end Champagnes and other sparkling wines outside the Champagne region. Wine makers discovered that they could press the grape softly to prevent the red pigment from the skin of the grape from leeching into the juice, so the bubbly produced from Pinot Noir is basically clear and "champagne" in color. Rosé Champagne's color is generally produced through the addition of red wine and is usually not due to the color of the main grape's skin. Pinot Noir is typically low in tannins while offering high acidity, making it both easy to drink when young as well as the perfect complement for a meal. Pinot Noir is a challenging grape, both in the vineyard and in the winery. This causes fluctuations in quality to be commonplace, and leads to disappointing products from some winemakers, even in a good year.