Pomace winemaking Flashcards
What are the three core principles of winemaking?
Selecting appropriate grapes, processing grapes into juice, managing fermentation to produce the desired wine style.
What are the key differences between pomace and pulp winemaking?
Pomace uses skin contact (especially in red wines), requiring management of maceration, cap, and phenolic extraction.
What are the main steps in pomace winemaking?
1) Pre-fermentation processing (de-stemming/crushing), 2) Alcoholic fermentation with skin contact, 3) Draining and pressing, and often 4) Malolactic fermentation (MLF).
Why are grapevine stems generally removed in pomace winemaking?
They are high in bitter tannins, potassium (which reduces acidity), and water (which dilutes wine); they also absorb colour and alcohol.
Why might stems be retained or added back in pomace winemaking?
To reduce cap compaction, assist heat dissipation, and add tannin or flavour (especially from ripe stems).
What are the goals of crushing in pomace winemaking?
Release juice for yeast, increase phenolic extraction, aerate must for fermentation start.
What are some crushing methods used in pomace winemaking?
Crusher rollers, must pumps, and traditional foot stomping.
Why must crushing be gentle?
To avoid releasing harsh tannins from stems/pips and prevent excessive lees or difficult processing.
What technique uses uncrushed grapes for unique flavours?
Carbonic maceration.
How is pomace fermentation similar to pulp fermentation?
Both follow the same yeast growth phases (lag, growth, stationary, decline) and are affected by pH, temp, SO₂, ethanol.
What are the major differences between pomace and pulp fermentations?
Fermentation temperature, pH/acidity changes, and monitoring/management needs.
Why is pomace fermentation generally warmer?
To promote extraction of colour, tannin, and flavour; typically between 20–30 °C.
Why can temperature control be challenging in red/pomace ferments?
Yeast generate heat, caps insulate, and fast fermentation increases heat load, making control difficult.
What ions in grape skins affect pH during pomace fermentation?
Potassium, which contributes to bitartrate formation and can raise pH.
What risks come with elevated pH after MLF in pomace wines?
Poor colour and flavour, reduced microbiological stability, increased oxidation, and reduced SO₂ effectiveness.
What pH management strategy helps stabilize pomace ferments?
Keep pH < 3.5 to encourage bitartrate precipitation and lower pH.
What problems can caps cause during fermentation?
Insulation (heat buildup), high yeast levels, drained liquid (poor extraction), and spoilage risk.
What are the benefits of cap management?
Removes heat, extracts tannin/colour/flavour, and prevents spoilage or wine faults.
