Doneness & Temps

Beverage Temperatures

Must Fermentation Temperature Ranges

Also: wine fermentation temperature, alcoholic fermentation temp, primary fermentation temperature, winemaking fermentation range

The temperature window during which grape must ferments alcoholically — cool for white-wine aromatics, warmer for red-wine colour and tannin extraction.

Must fermentation temperature is one of the most consequential decisions in winemaking. White and sparkling musts ferment cool, typically 12–18°C, to preserve volatile aromatic esters (isoamyl acetate, ethyl hexanoate) and delicate floral thiols that would be driven off at higher temperatures. Red musts ferment warmer, typically 25–30°C, because heat favours colour and tannin extraction from grape skins via enhanced anthocyanin and phenolic solubility, and because red wines tolerate — often benefit from — Maillard-adjacent complexity. Ambient temperature also strongly influences yeast strain selection and pacing.

In photos

Must Fermentation Temperature Ranges at White/sparkling must: 12–18°C (54–64°F); Red must: 25–30°C (77–86°F); Rosé: 14–18°C (57–64°F). Yeast (primarily Saccharomyces cerevisiae) converts glucose and fructose to ethanol and CO₂. Visual cues: Active fermentation: vigorous CO₂ bubbling in a white fermenter indicates healthy yeast at 15–18°C, Aroma profile developing — floral, fruity esters signal correct cool-temperature white fermentation, Red fermenting cap (grape skins) rises within 12–24 hours of inoculation at correct warm temperature.
Must Fermentation Temperature Ranges at White/sparkling must: 12–18°C (54–64°F); Red must: 25–30°C (77–86°F); Rosé: 14–18°C (57–64°F). Yeast (primarily Saccharomyces cerevisiae) converts glucose and fructose to ethanol and CO₂. Visual cues: Active fermentation: vigorous CO₂ bubbling in a white fermenter indicates healthy yeast at 15–18°C, Aroma profile developing — floral, fruity esters signal correct cool-temperature white fermentation, Red fermenting cap (grape skins) rises within 12–24 hours of inoculation at correct warm temperature.
Must Fermentation Temperature Ranges in context — the stages just below and above, side-by-side. Must fermentation temperature is one of the most consequential decisions in winemaking. Target reference White/sparkling must: 12–18°C (54–64°F); Red must: 25–30°C (77–86°F); Rosé: 14–18°C (57–64°F).
Must Fermentation Temperature Ranges in context — the stages just below and above, side-by-side. Must fermentation temperature is one of the most consequential decisions in winemaking. Target reference White/sparkling must: 12–18°C (54–64°F); Red must: 25–30°C (77–86°F); Rosé: 14–18°C (57–64°F).
Must Fermentation Temperature Ranges in practice — Chardonnay fermentation (cool tank, 14–16°C for Chablis style; warmer barrel for Burgundian style). Different commercial yeast strains have different optimal temperature ranges.
Must Fermentation Temperature Ranges in practice — Chardonnay fermentation (cool tank, 14–16°C for Chablis style; warmer barrel for Burgundian style). Different commercial yeast strains have different optimal temperature ranges.

What happens

Yeast (primarily Saccharomyces cerevisiae) converts glucose and fructose to ethanol and CO₂. At cool temperatures, yeast metabolism slows, ester synthesis pathways are favoured, and volatile aromatic compounds are retained in solution rather than stripped by CO₂ evolution. At warmer temperatures, yeast metabolism accelerates, phenolic extraction from skins is enhanced (skins are macerated in red fermentation), and a broader range of fermentation by-products — including glycerol contributing to body — forms. Above 35°C, fermentation risks 'sticking' as yeast die; below 10°C, fermentation may not start or will stall.

What to look for

  • Active fermentation: vigorous CO₂ bubbling in a white fermenter indicates healthy yeast at 15–18°C
  • Aroma profile developing — floral, fruity esters signal correct cool-temperature white fermentation
  • Red fermenting cap (grape skins) rises within 12–24 hours of inoculation at correct warm temperature
  • Must temperature rising rapidly (more than 2–3°C per hour) signals a runaway fermentation requiring cooling
  • Colour in red must deepens visibly day by day as anthocyanins extract at 25–30°C

How to check

  • Stainless steel tanks: read the jacketed cooling system thermostat; verify with a probe thermometer inserted into the must
  • Oak barrels or open-top fermenters: use a waterproof digital thermometer pushed below the surface, away from the CO₂-generating cap
  • Monitor twice daily — fermentation generates heat (exothermic); active ferment can raise temperature 5–8°C above ambient without cooling
  • For home winemaking, a floating wine thermometer in the carboy gives adequate readings

The science behind it

  • Saccharomyces cerevisiae

    Primary wine yeast; optimal activity range 15–30°C, dies above 35°C

  • Malolactic fermentation (MLF)

    Secondary bacterial fermentation (Oenococcus oeni) converting malic to lactic acid; occurs after primary at 18–22°C

  • Anthocyanin extraction

    Colour compounds from red grape skins are more soluble at warmer temperatures; the basis for warm red fermentation

  • Ester formation

    Fruity aromatic esters synthesised by yeast are more volatile at high temperatures and are retained better with cool fermentation

  • Stuck fermentation

    Fermentation that halts prematurely due to excess heat, nutrient deficiency, or alcohol toxicity

Appears in

Chardonnay fermentation (cool tank, 14–16°C for Chablis style; warmer barrel for Burgundian style)Sauvignon Blanc fermentation (12–14°C to preserve thiols)Champagne base wine fermentation (10–15°C)Cabernet Sauvignon red fermentation with pump-overs (28–30°C)Pinot Noir open-top fermentation with punch-downs (26–28°C)Carbonic maceration (Beaujolais Nouveau) at 30–32°C in whole-cluster CO₂ environment

References

  1. 1.Winemaking: From Grape Growing to Marketplace — Richard P. Vine et al.
  2. 2.The Science of Wine: From Vine to Glass — Jamie Goode
  3. 3.Understanding Wine Technology — David Bird MW
  4. 4.Wine Production and Quality — Keith Grainger & Hazel Tattersall

Confidence: high

Notes

Yeast strain sensitivity

Different commercial yeast strains have different optimal temperature ranges. EC-1118 (used in Champagne) is cold-tolerant and can ferment at 10°C; Rhône strains for red wine are bred for activity at 28–32°C. Matching strain to target temperature is as important as the temperature itself.

Maceration and temperature interplay in reds

Red fermentation temperature governs not just fermentation rate but extraction kinetics. A winemaker can choose a warm, short fermentation (3–5 days at 30°C) for fresh-fruity reds, or a cool, extended maceration (10–14 days at 22–25°C) for structured wines — the temperature is a dial controlling the tannin-to-fruit ratio as much as fermentation pace.