Extended Maceration

Extended maceration, which the AWRI calls extended post-fermentation maceration, means leaving grape skins, seeds and any stems in contact with the wine for a length of time after primary fermentation is complete and before pressing. The AWRI says the technique is almost exclusively used in red winemaking, and that its aim is to increase the extraction of phenolic compounds from the skins, seeds and any stems in order to optimise the color, flavor and tannin structure of the wine. Decanter describes it in the same terms: leaving red wine in contact with skins, stalks and seeds after fermentation has finished. Maceration ends once the skins, seeds and stems are removed, according to Decanter. The practice is old: Roagna, a Barbaresco producer, says that in the Langhe its ancestors would leave the must in contact with the grape skins for months.

• Distinct from a cold soak: Decanter notes that maceration often refers to cold-soaking unfermented grape juice with the crushed skins, seeds and stalks before fermentation, whereas extended maceration comes after fermentation has finished.
• The AWRI calls the length of time that skins and seeds stay in contact with the juice or wine, during both fermentation and any post-fermentation maceration, probably the most critical factor in defining the phenolic profile and sensory properties of the wine, and one of the easiest to control.
• Extended maceration is traditional in Burgundy with Pinot Noir, Bordeaux with Cabernet-family varieties and Piedmont with Nebbiolo, and to a lesser extent in the Rhône Valley with Shiraz and associated varieties, according to the AWRI.

According to the AWRI's 2018 Ask the AWRI column, the greatest changes in wine composition from extended maceration are an increase in total phenolics and a decrease in anthocyanins as they are incorporated into non-bleachable pigments, including pigmented tannins. Some of the anthocyanin loss has also been attributed to oxidative degeneration and to adsorption onto fermentation solids. This can make the color of a young wine appear more advanced, but the AWRI notes that non-bleachable pigments are a more stable form of color than anthocyanins, and one study found minimal differences in color between extended maceration and control wines after 400 days. Contact with seeds can extract seed tannins linked to bitterness: in many studies extended-maceration wines were rated higher for bitterness, which the AWRI says is often attributed to seed tannins or flavan-3-ol monomers such as catechin, and the extraction of these compounds continues throughout the extended maceration.

• Steadily increasing pH and decreasing ethanol with longer maceration have been reported, though the AWRI notes that the ethanol decrease is not seen in all studies and in some cases ethanol increases.
• In one study of Duras cited by the AWRI, the black pepper compound rotundone fell by 23% when maceration was lengthened from eight to 14 days.
• An increase in polysaccharide concentration has also been reported, but the AWRI says the trends differ depending on variety and harvest date.
• Three studies by the Harbertson research group at Washington State University, with 30-day macerations of Cabernet Sauvignon and Merlot, found that between 73% and 79% of the tannins in the wines were derived from the seeds (AWRI, 2018).

The AWRI says post-fermentation maceration is best performed in sealed vessels, because if the cap of skins and seeds is exposed to oxygen or to vinegar flies, acetaldehyde, acetic acid and ethyl acetate may be formed. During fermentation winemakers punch down the cap or pump wine over it, according to Decanter, but once post-fermentation maceration begins the AWRI says the cap is usually submerged and the container topped up so that there is no ullage. In the first few days the volume of wine can rise or fall, mainly with temperature changes and residual fermentation, so the AWRI advises checking the tank regularly and leaving space for expansion. A fine mist of SO2 solution may be sprayed onto the wine's surface before the tank is sealed, and repeated periodically, to discourage film-forming yeast and acetic acid-producing bacteria. The AWRI says malolactic fermentation should be initiated during primary fermentation and is invariably complete by the conclusion of post-fermentation maceration. The technique is usually carried out in the same vessel used for fermentation, so additional fermentation capacity is needed if it is adopted.

• To keep the cap away from oxygen and vinegar flies during extended post-fermentation maceration, the AWRI says the process is best performed in a sealed vessel, with the cap usually submerged and the container topped up so that there is no ullage.
• Tasting alone is an unreliable guide, because the AWRI says it is virtually impossible to obtain a representative sample during extended maceration, which can make the level of extraction very difficult to judge by sensory assessment.
• The AWRI says it is not possible to be prescriptive about the ideal length, because the initial concentration of grape phenolic compounds and their extractability vary with variety and season; previous experience with the variety and region, and recognition of seasonal differences in fruit composition, are important in deciding it.
• A 2009 survey of Australian winemakers by Joscelyne found that more winemakers would use the technique if not for the costs and logistical pressures of needing greater fermentation capacity, according to the AWRI.

The AWRI says extended post-fermentation maceration can result in large changes in both the chemical composition and the sensory characteristics of wine. In many studies, extended-maceration wines were rated higher for bitterness in formal sensory evaluation; the AWRI notes this does not appear to be widely reported in commercial wines but is clearly a potential risk. Increased astringency has also been reported in many studies, and greater astringency would be expected as overall tannin concentration rises. Young wines may appear more advanced in color, because anthocyanins are incorporated into more stable non-bleachable pigments. The AWRI also cites La Follette's 1996 view that it is better to press at dryness than go halfway on a maceration, because tough tannins grip the wine before it smooths out at the end of the extended contact, while noting there appear to be few sensory studies to support that assertion.

• Bitterness and overly astringent tannins are the most commonly reported sensory risks, according to the AWRI.
• Barolo traditionalist Mauro Mascarello told Decanter that he picks very ripe, sometimes a little over-ripe, grapes to avoid bitter tannins from underripe pips when making long-macerated wines.
• The oenologist Donato Lanati, writing to Mauro Mascarello, said long macerations will extract grape-seed tannins, which therefore need to be ripe, and may bring some loss of color (Decanter).

In Piedmont, maceration length divides Barolo producers. Writing in Decanter, Stephen Brook described traditionalists as favouring a long, slow vinification followed by prolonged ageing in large oak casks, and modernists as, by and large, favouring shorter macerations and more overt fruitiness, often with barrique ageing. He wrote that traditionalists such as Mauro Mascarello, Bartolo Mascarello and Giovanni Conterno were prepared to macerate for 30 days or more, which inevitably extracts more tannins than a briefer period. Modernist pioneers including Elio Altare, Domenico Clerico, Roberto Voerzio and Angelo Gaja were persuaded of the virtues of shorter vinifications and barrique ageing by their visits to Burgundy and Bordeaux, according to Brook. In Barbaresco, Roagna says its wines macerate for an average of 60 to 100 days under a submerged cap. Rivetto says its Briccolina Barolo undergoes very long macerations during vinification. In Oregon's Willamette Valley, Fullerton Wines says it left the skins in contact with the finished wine for 100 days in 2013 and has since fine-tuned its extended maceration period to 30 days. In Australia, a 2009 survey found the technique most commonly used with Cabernet Sauvignon, followed by Shiraz, Merlot and Pinot Noir, according to the AWRI.

• Renato Ratti argued, according to Decanter, that the so-called traditional methods were an aberration brought on by labor shortages during periods of war and economic crisis, when breaking up the cap gave way to keeping it submerged, which maximised tannin extraction.
• Roagna says Giovanni Roagna drew off his Nebbiolo wines just before Christmas, sometimes waiting until the January after harvest, using the submerged cap technique of closing the top of the wooden vats with oak planks.
• Fullerton Wines runs its extended maceration in rotator barrels, 500 L puncheons on a rotating stand, and says vintage variation will always require it to monitor and adjust the maceration period.
• The AWRI ran extended post-fermentation maceration treatments of 21 and 60 days in its 2018 Cabernet trial.

Extended maceration sits at the end of a sequence of skin-contact decisions. Before fermentation, a cold soak holds unfermented juice with the crushed skins, seeds and stalks to leach tannins, anthocyanins and flavor compounds, according to Decanter. During fermentation, punching down puts the skins back in contact with the wine and increases extraction of color and phenolics, while pumping over results in less extraction and suits more delicate varieties. After fermentation, the AWRI recommends a cautious approach to extended maceration: start with a small batch and assess the results over time. Blending trials can also be conducted to establish the proportion of extended-maceration wine needed to achieve the desired sensory effects.

• There is no clear formula for the ideal length of maceration, the AWRI says, because it depends on the variety and the season.
• Blending trials help determine how much extended-maceration wine is needed for the desired sensory effect, according to the AWRI.
• One study cited by the AWRI found that total yeast concentration increased until day 40 of a 90-day maceration, with neither Brettanomyces nor acetic acid bacteria detected at any stage.

Primary sources (the Australian Wine Research Institute, and Roagna, Fullerton Wines and Rivetto for their own winemaking): https://www.awri.com.au/industry_support/winemaking_resources/winemaking-practices/winemaking-treatment-extended-post-fermentation-maceration/, https://www.awri.com.au/wp-content/uploads/2018/11/s2045.pdf, https://www.roagna.com/en/manifesto-roagna/macerazione-lunga-a-cappello-sommerso/, https://fullertonwines.com/rotator-barrels-labor-of-love/, https://rivetto.it/en/vini/barolo-docg-briccolina/. Secondary: https://www.decanter.com/learn/what-does-maceration-mean-ask-decanter-442910/, https://www.decanter.com/premium/barolo-ancient-and-modern-247758/. Last verified 2026-09-29