Racking (Soutirage) — Timing, Frequency & Wine Style Impact

Racking is the controlled transfer of wine from one vessel (barrel, tank, or carboy) to another, leaving behind settled solids including dead yeast cells forming the gross lees, tartrate crystals, and other particulates. Alexis Lichine's Encyclopedia of Wines and Spirits defines racking as siphoning wine off the lees into a new, clean barrel or other vessel. The process is also known as soutirage or soutirage traditionnel in French, Abstich in German, and travaso in Italian. It is distinct from bottling-time decanting because racking occurs at planned winemaking intervals, often paired with SO₂ additions, and uses gravity-fed or pump-assisted systems to control oxygen exposure.

• Separates clear wine from gross lees (heavy sediment: grape seeds, skins, and dead yeast) and fine lees (lighter colloidal yeast particles that settle more slowly)
• Performed using gravity, siphon tubes with a racking cane, or pumps; a sight glass allows the winemaker to halt transfer before sediment is drawn up
• Timing and aeration level vary greatly: aggressive splash racking for young reds versus protective submerged-hose racking for delicate whites

Dissolved oxygen (DO) uptake is the critical variable in every racking. Splash racking, where wine is discharged against the side of the receiving vessel, introduces dramatically more oxygen than submerged-hose racking, with research citing a difference of 12-fold or more between the two techniques. Dissolved oxygen during racking can approach saturation at 6 to 9 mg/L depending on temperature and equipment. Winemakers can minimise oxygen uptake by purging transfer lines and receiving vessels with inert gas. CO₂ and argon (both denser than air) are the most practical choices for blanketing headspace; nitrogen, though widely used to push hose lines in commercial cellars, has a similar density to air and is less effective for headspace blanketing. Inert gas management, paired with careful pump maintenance to prevent leaky seals, is essential for producing reductive-style whites and premium Pinot Noirs.

• Gross lees settle within 24 to 48 hours post-pressing; fine lees settle more slowly and may take several weeks, offering winemakers a choice about how long to delay racking
• Oxygen uptake during racking triggers tannin polymerization and anthocyanin stabilization in red wines, softening texture and deepening color over time
• Protective racking under CO₂ or argon blanket introduces minimal DO, preserving reductive, fruit-forward aromatics in whites and light reds

Racking frequency and technique fundamentally shape wine character. Frequent racking accelerates oxidative aging, promotes tannin polymerization, softens astringency, and deepens color stability, all desirable for age-worthy reds. This process also removes CO₂, which can be beneficial for red wines but detrimental to whites and rosés where some dissolved gas provides freshness and a protective buffer. Low-racking or minimal-racking approaches preserve reductive, fruit-forward aromatics and brighter acidity, common in natural wine production and for aromatic white varieties. Extended lees contact (sur lie), where racking off fine lees is delayed or omitted, releases mannoproteins and polysaccharides through autolysis, adding creamy mouthfeel and yeasty complexity, as famously seen in Muscadet, white Burgundy, and Champagne.

• Frequent racking with aeration: deeper color, suppler tannins, earlier approachability, and slower primary fruit degradation in red wines
• Minimal racking: fresher fruit, higher perceived acidity, more primary aromatics, and a more reductive character at release
• Sur lie (no or delayed racking of fine lees): autolytic notes of brioche, almond, and cream; mannoproteins improve texture; risk of hydrogen sulfide if gross lees are not removed promptly

Racking timing is calibrated to fermentation progress, lees settlement, and malolactic fermentation (MLF) status. For red wines, an initial rack typically follows pressing, allowing gross lees to settle for a day or two before the wine moves to the aging vessel. Many winemakers delay further racking until MLF is complete, as lees provide nutrients for lactic acid bacteria and maintain a reductive environment that MLF bacteria prefer. In Bordeaux, the benchmark is racking every three to four months during barrel aging. For most white wines, racking is kept to a minimum to limit oxygen exposure; the reference clarification approach is cold settling by gravity for 24 to 48 hours (débourbage) followed by a protective rack into the fermentation vessel. Wines destined for extended lees contact, such as Chablis, Muscadet, and barrel-fermented Chardonnay, may remain on fine lees for months with periodic batonnage rather than racking.

• Post-pressing rack for reds: after one to two days of gross lees settling, before or after MLF depending on style
• Bordeaux benchmark: racking every three to four months during barrel aging to clear lees and add controlled oxygen
• White wine débourbage: cold settling at 10 to 15°C for 24 to 48 hours removes 60 to 80% of suspended solids before fermentation begins

In Burgundy, red wines spend between 12 and 24 months in barrel and whites between 8 and 16 months, with racking decisions left to each producer. The winemaker decides how many times the wine needs to be racked to produce the desired aromas, and the process is used both to remove lees and to add controlled oxygen. In Bordeaux, during barrel aging the wine is racked to clear it of lees, though some producers are now challenging this practice, finding that lees contact adds richness. Minimal-intervention and natural wine producers may rack only once or not at all after MLF, deliberately preserving fine lees to maintain a reductive environment and encourage autolytic complexity. Micro-oxygenation has emerged in Bordeaux as an alternative to racking, allowing oxygen to be added in precisely controlled amounts during elevage, something racking cannot achieve with the same precision.

• Burgundy: red wines aged 12 to 24 months in barrel; whites 8 to 16 months; racking frequency varies by producer style and appellation
• Bordeaux: racking every three to four months is the benchmark; estates in Pomerol and St-Emilion still use gravity-fed soutirage traditionnel
• Natural and minimal-intervention producers: reduced racking to preserve fine lees, primary aromatics, and a reductive winemaking environment

Racking is routinely paired with SO₂ additions to protect wine from oxidation and spoilage microbes. Each racking event that exposes wine to oxygen will consume approximately 10 to 12 ppm of free SO₂, so additions are planned accordingly. A common approach is to add 30 to 50 ppm free SO₂ at the first post-fermentation rack, then monitor and top up at subsequent racks to maintain target free SO₂ levels. Wines destined for MLF should not receive SO₂ at first racking, as lactic acid bacteria are highly sensitive to sulfite; SO₂ is added after MLF is confirmed complete. Extended lees contact is timed around MLF completion for wines like white Burgundy, Chablis, and Muscadet, where fine lees add texture and reductive protection. Conversely, early removal from gross lees is recommended to prevent hydrogen sulfide formation, since H2S develops when yeast cells under stress or on heavy lees produce sulfide compounds detectable at levels as low as 1 to 2 micrograms per liter.

• SO₂ management at racking: approximately 10 to 12 ppm free SO₂ consumed per racking event; additions of 30 to 50 ppm typically made at first post-fermentation rack
• MLF timing: racking delayed until MLF is complete for wines seeking secondary fermentation; SO₂ withheld until MLF is confirmed to avoid inhibiting lactic acid bacteria
• Hydrogen sulfide prevention: early removal from gross lees, adequate yeast-assimilable nitrogen (YAN) during fermentation, and prompt racking reduce risk of reductive off-aromas