Photo by Behnam Norouzi on Unsplash
Winemakers control the duration of fermentation by managing several key factors that influence how long the yeast remains active in converting the sugar in the grape juice to alcohol.
Here’s are some ways a wine maker can control the length of fermentation:
— Controlling Fermentation Temperature:
Cooler temperatures (e.g., 10–15°C or 50–59°F) slow down fermentation thus extending the process
Warmer temperatures (e.g., 20–30°C or 68–86°F) speed up the fermentation rate
— Selecting the Yeast Strain:
Different strains of yeast have different fermentation rates and tolerances
Some yeasts ferment quickly and efficiently, while others work more slowly or produce more complex flavors
— Adjusting the Sugar Content (Brix Level):
Winemakers can adjust this by harvesting grapes at different ripeness levels or by adding sugar (a.k.a., chaptalization) which is rarely done
More sugar means a longer fermentation, since the yeast has more to consume
— Adding Nutrients:
Adding nutrients, such as nitrogen, can keep yeast healthy and extend or support the fermentation process
A lack of nutrients can cause fermentation to end early
— Limiting Oxygen Exposure:
Yeast needs a small amount of oxygen early on in order to multiply. Limiting the fermenting grapes oxygen exposure later in the process can help finish fermentation more efficiently
— Intentionally Stopping Fermentation:
Winemakers can stop fermentation early to retain sweetness by:
Lowering the temperature rapidly
Adding sulfur dioxide (SO₂) or alcohol to kill or inhibit yeast
Filtration to physically remove the yeast
While typical wine fermentation durations vary depending on the type of wine, fermentation temperature, and winemaking goals, here are general guidelines:
Red Wines: Primary fermentation: 5 to 10 days
White Wines: Primary fermentation: 10 to 21 days
Rosé Wines: Typically similar to white wine fermentation in duration and temperature: 10 to 14 days
Sparkling Wines (Traditional Method):
Primary fermentation: like white wines, 10 to 21 days
Secondary fermentation: 1 to 3 months, followed by aging on lees for months or years