pomace

Pomace in a bladder press. These are Chardonnay grapes left over after pressing.

Pomace (pronounced /ˈpʌmɪs/, PUM-is) is the solid remains of grapes, olives, or other fruit after pressing for juice or oil. It contains the skins, pulp, seeds, and stems of the fruit. The OED cites the term marc as having the same meaning.

Grape pomace has traditionally been used to produce pomace brandy — the OED also uses the term marc brandy — (such as grappa) and grapeseed oil. Today, it is mostly used as fodder or fertilizer.

Oenocyanin, a natural red dye and food coloring agent, is produced from grape pomace. Some companies also recover tartrates (cream of tartar) and grape polyphenols from grape pomace.^[1]

History

“Pomace” is derived from the Latin “pomum” (apple). The English were the first to use the term “pomace” to refer to the byproduct of cider production.^[1]

Look up faux in Wiktionary, the free dictionary.

In the Middle Ages, pomace wine with a low alcohol content of three or four percent was widely available. This faux wine was made by adding water to pomace and then fermenting it. Generally, medieval wines were not fermented to dryness; consequently the pomace would retain some residual sugar after fermenting.

Piquette

The Ancient Greeks and Romans would use pomace to create a wine later known as piquette. This was a low-end wine that was normally given to slaves and common workers. After the wine grapes were pressed twice, the pomace was soaked in water for a day and pressed for a third time. The resulting liquid was mixed with more water to produce a thin, weak wine.^[2]

Wines & brandies

Apple pomace is often used to produce pectin, or can be used to make ciderkin, a weak cider, while grape pomace is used to produce pomace wine and pomace brandy, such as grappa (in Italy), marc (in France), zivania (in Cyprus), lozovača or komovica (in Croatia), Arak (in Iran), Raki (in Turkey and Albania), Orujo (in Spain), Tsikoudia (in Crete), Tsipouro in northern Greece or bagaço (in Portugal). There are many other local names and variants such as the English "press cake".^[1] Essentially all wine-producing cultures started making some form of pomace brandy once the principles of distillation were understood.

Winemaking

The components of pomace in winemaking differs on whether white or red wine is being produced. In red wine production, pomace is produced after the free run juice (the juice created before pressing by the weight of gravity) is poured off, leaving behind dark blackish-red debris consisting of grape skins, stems, as well as dead yeast cells. The color of red wine is derived from skin contact during the maceration period which can sometime include partial fermentation. The resulting pomace is more alcoholic and tannic than pomace produced from white wine production. In white wine production, the grapes are quickly pressed after crushing in order to avoid skin contact with pomace being a byproduct of the pressing. The resulting debris is a pale, greenish-brown color and contains more residual sugars than it contains tannins and alcohol. This is the pomace normally used in brandy production.^[1]

Other uses

Grape pomace from wineries in the Barossa Valley, South Australia. Top, white grape pomace; bottom, red grape pomace.

Pomace is produced in large quantities in wine production with the issue of disposal being an important environmental consideration. Some wineries will reuse the material as fertilizer while others are exploring options of selling the used pomace to biogas companies to be used in the creation of renewable energy. As envisioned, pomace would be introduced into anaerobic digesters that contain microorganisms that aid in its decomposition and produce methane gas that could be combusted to generate power.^[3] However, such digesters of pomace are not yet commercially viable.^{[citation needed]}

Studies have also shown that specific polyphenols in red wine pomace may be beneficial for dental hygiene. A study conducted at the Eastman Dental Center found that these polyphenols interfere with Streptococcus mutans, the bacteria in the mouth which causes tooth decay. Professor Hyun Koo, the lead researcher of the study, hopes to isolate these polyphenols to produce new mouthwashes that will help protect against cavities.^[4]

A 2004 study conducted by Erciyes University in Turkey found that pomace can also act as a natural food preservative that interferes with E. coli, Salmonella and Staphylococcus bacteria. Researchers used the dried pomace from the white Turkish wine grape Emir Karasi and red Kalecik Karasi to produce a powder that was mixed with ethyl acetate, methanol or water and exposed to 14 different types of food bacteria. The results showed that all 14 bacteria were inhibited to some degree by the pomace — depending on the grape variety and the concentration of the extract. The red wine grape Kalecik Karasi was shown to be the most effective; the study researchers believed this was due to the higher concentration of polyphenols in red wine grape skins.^[5]

See also

• Biodegradable waste
• Ancient Greek cuisine
• Brös
• Fruit wine

References

External links

• Alison Crowe "The Pomace Predicament" WineMaker Magazine, August 2005
• Y. D. Hang and E. E. Woodams "Grape pomace: A novel substrate for microbial production of citric acid" Biotechnology Letters, Volume 7, Number 4 / April, 1985
• Definition of marc as synonym from winesoftheworld.com