Pomace (/ˈpʌməs/PUM-əs), ormarc (/ˈmɑːrk/; from Frenchmarc[maʁ]), is the solid remains ofgrapes,olives, or otherfruit afterpressing forjuice oroil. It contains the skins, pulp, seeds, and stems of the fruit.
Grape pomace has traditionally been used to producepomace brandy (such asgrappa,orujo,törkölypálinka,tsipouro,tsikoudia,zivania). Today, it is mostly used asfodder, asfertilizer, or for the extraction of bioactive compounds likepolyphenols.[1]
TheEnglish wordpomace derives fromMedieval Latinpomaceum ("cider") andpomaceus ("pomaceous, appley"), fromClassical Latinpomum ("fruit,apple").[2] The word was originally used for cider and only later applied to the apple mash before or after pressing, via various cognate terms in northernFrenchdialects, before being used for such byproducts more generally.[2]
Theancient Greeks andRomans used grape pomace to create an inferior class ofwine given toslaves and laborers. The grapes were first pressed twice and the resulting pomace was then soaked in water for another day and pressed a third time andfermented. The resulting liquid produced a thin, weak, and thirst-quenching wine with analcohol content around 3 or 4%, now known aspiquette in English and French and asgraspia orvin piccolo inItalian.[3] Piquette was also widely available during theMiddle Ages. As medieval wines were not usually fermented todryness, medieval piquette retained a degree ofresidual sugar.
Pomace from various sources—particularly fish andcastor beans—was also used in theearly modern period forfertilizer.[2]
Olive pomace, the byproduct ofolive oil extraction, was widely used throughoutclassical antiquity as an alternativefuel source towood andcharcoal.[4] Use of olive pomace peaked in theRoman era, when, due tourban growth andproto-industrial activity,markets forimported olive pomace developed.[4] Olive pomace may besun-dried or made into charcoal for use as fuel.[4]
Apple pomace is often used to producepectin and can be used to makeciderkin, a weakcider, as well aswhite cider, a strong and colourless alcoholic drink.[5]
Grape pomace is used to producepomace brandy andpiquette. Most wine-producing cultures began making some type of pomace brandy after the principles ofdistillation were understood.
Pomace inwinemaking differs, depending upon whether white wine 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 ofgravity) is poured off, leaving behind dark blackish-red pomace consisting of grape skins and stems. The color of red wine is derived from skin contact during themaceration period, which sometimes includes partial fermentation. The resulting pomace is more alcoholic andtannic than pomace produced from white wine production. Pomace from the Italian wineAmarone is macerated inValpolicella wine to produceRipasso.[citation needed]
In white wine production, grapes are separated from their skins, then pressed to obtain juice. The skin pomace is a pale, greenish-brown color, and containsresidual sugars andtannins. This pomace is used in brandy production.[6]
Pomace is produced in large quantities in wine production, making its disposal an important environmental consideration. Some wineries use the material as fertilizer, while others are selling it tobiogas companies forrenewable energy. As envisioned, pomace would be introduced intoanaerobic digesters that containmicroorganisms that aid in itsdecomposition and producemethane gas that could be burnt to generate power.[7]
Specificpolyphenols in red wine pomace may be beneficial fordental hygiene. A study conducted at the Eastman Dental Center found that these polyphenols interfere withStreptococcus mutans, thebacterium in the mouth that causestooth decay. ProfessorHyun Koo, the lead researcher of the study, hoped as of 2008 to isolate these polyphenols to produce newmouthwashes that will help protect against cavities.[8]
Grape pomace is also used in the oil and gas industry as alost circulation material in oil-based drilling muds due to the pomace being fibrous and tannin-rich.
A 2004 study conducted byErciyes University inTurkey found that pomace can also act as a naturalfood preservative that interferes withE. coli,Salmonella andStaphylococcus bacteria. Researchers pulverised the dried pomace from the whiteTurkish wine grapeEmir Karasi and redKalecik Karasi grapes; this was mixed withethyl acetate,methanol or water and exposed to 14 different types of food bacteria. 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 Kalecik Karasi grape was the most effective; the researchers believed this was due to the higher concentration of polyphenols in red wine grape skins.[9]
Oenocyanin, a natural red dye and food-coloring agent, is produced from grape pomace. Tartrates (potassium bitartrate, 'cream of tartar') andgrape polyphenols can also be manufactured from grape pomace.[6]
Apple pomace has long been a traditional feed for various kinds of livestock.[10] The use of grape pomace as livestock feed is encouraged in order to reduce the release of grape processing residues in the environment, which can lead to serious pollution.[11]
Apple pomace was used, in conjunction withwhey, to flavor the first iteration ofFanta soft drink inGermany duringWorld War II. This was done because wartime embargoes limitedCoca-Cola of Germany's ability to import and manufacture the American beverage.
Apple pomace can also be milled in order to createapple flour, also known as apple pomace flour.
Pomace was once used as an ingredient in somepaints, but today such use is limited toartisanal paints in such applications asfine arts orarchitectural restoration, whereas for industrial and commercial paints it is now superfluouspetrochemically.
According to the CanadianFood and Drug Regulations, pomace can be a potable alcoholic distillate or a mixture of potable alcoholic distillates obtained by distilled skin and pulp of sound ripe fruit after removal of the fruit juice, wine or fruit wine. Pomace may contain caramel, fruit, botanical substances, flavoring and flavoring preparations. Pomace may be described on its label as "(name of the fruit) Pomace" or "(name of the fruit) Marc" if all of the skin and pulp of the fruit used to make the pomace originate from the particular fruit.[12]
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