How Wine Is Made
A complete Level 1 overview of the winemaking process from grape to glass
Learning Objectives
- Describe the main stages of winemaking from harvest to bottling
- Explain what happens during alcoholic fermentation
- Distinguish between how red and white wines are made differently
- Identify the role of oak, acidity, and tannin in finished wines
From Grape to Must
Winemaking begins at harvest, when grapes are picked either by hand or machine. The timing of harvest is critical — earlier picking preserves acidity and freshness, while later picking develops sugar, flavour, and potential alcohol. Once harvested, grapes are destemmed and crushed to release juice, known as must. For white wines, the skins are typically removed at this stage before fermentation begins.
Alcoholic Fermentation
Fermentation is the conversion of grape sugars into alcohol and carbon dioxide by yeasts. It typically takes place in stainless steel tanks or oak barrels. Winemakers can use wild (indigenous) yeasts naturally present on the grape skins, or add cultured commercial yeasts for consistency. Fermentation generates heat, so temperature control is important — cooler temperatures preserve delicate aromas, while warmer temperatures extract more colour and tannin.
Red vs White Winemaking
The key difference between red and white winemaking is skin contact. For red wines, the skins remain in contact with the juice throughout fermentation to extract colour, tannin, and flavour compounds (phenolics). Winemakers use techniques like pumping over (remontage) or punching down (pigeage) to keep the skins submerged. White wines ferment without their skins, giving lighter colour and less tannin. Rosé wines are made either by brief skin contact or by blending.
Maturation and Finishing
After fermentation, wines are matured in containers — stainless steel preserves freshness, while oak barrels add complexity, vanilla, and spice. Many red wines and some whites undergo malolactic fermentation (MLF), which converts sharp malic acid into softer lactic acid, reducing perceived acidity and adding buttery texture. Finally, wines may be fined (to clarify) and filtered before bottling.
Key Vocabulary
Exam Question Examples
Describe two differences in the winemaking process for red and white wines.
Approach
Focus on skin contact (maceration for reds, none for whites) and fermentation temperature. Mention tannin and colour extraction from skins as the key consequence for red wines.
What is malolactic fermentation and what effect does it have on wine style?
Approach
Define MLF as bacterial conversion of malic to lactic acid. State that it softens acidity and adds a creamy, buttery texture. Note that it is common in red wines and some fuller white wines like Chardonnay.
Quick Summary
- 1.Harvest timing affects sugar, acidity, and flavour concentration
- 2.Alcoholic fermentation converts sugars to alcohol via yeasts
- 3.Red wines ferment with skins for colour and tannin; white wines do not
- 4.Malolactic fermentation softens acidity and adds a buttery texture
- 5.Maturation in oak adds complexity; stainless steel preserves freshness
Practice questions on this topic
Frequently Asked Questions
- What is the difference between fermentation and maceration?
- Fermentation is the conversion of sugars into alcohol by yeasts. Maceration is the process of steeping grape skins in the must or wine to extract colour, tannin, and flavour compounds. For red wines, both happen simultaneously during primary fermentation.
- Why do some wines taste buttery?
- A buttery flavour in wine typically comes from malolactic fermentation (MLF), which produces a compound called diacetyl. Chardonnay is the most famous example of a white wine with buttery character from MLF, especially those aged in oak.
- What is the purpose of fining wine?
- Fining removes unwanted particles, proteins, and tannins that could cause cloudiness or off-flavours. Common fining agents include bentonite (clay), egg white, and isinglass (fish gelatin). Fined wines are clearer and more stable.
Consolidate your knowledge
Use Vinlecta to practise exam-style questions on how wine is made and related topics under timed conditions.
Related study guides: