Vin-Q
Brut Nature rosé record
Production document

Step 2 — Fermentation

The fermentation as run, including the microbial decision and the assemblage or blending gate.

Source: products/cava/02_process/step2_ferment/INDEX.md Download the original

02 Process Step 2 — Fermentation & Assemblage: Cava — El Celestial Ouroboros Mark III

Process Summary

Three parallel fermentations (T1 reductive, T2 wild-complexity, Garnatxa standard) → Universal Acidification Triage (Escudo Ácido) at <8°C, pH 3.25 → Lees Sélection (T1 smell-check; T2 fine-layer only, CO₂ blanket) → Bio-Integration in 1,800 L tank, 7-day window → Tirage with EC1118 → 36-month bottle aging.

This step covers everything from the start of fermentation through the assemblage and the in-tank bio-integration. The bottle aging is covered in step3_bottling.

Process Stages

  1. Parallel fermentations (T1 at 25–27°C; T2 cold-soak then 22–24°C; Garnatxa moderate)
  2. Día 0: Acid Shield — cool all tanks <8°C; acidify each to pH 3.25
  3. Día 1: Garnatxa integration — wine + lías to main assemblage tank
  4. Día 1: T1 selection — smell-check; if H₂S, splash-rack and discard lías; if clean, pump wine + lías
  5. Día 1: T2 critical step — NO splash; CO₂ blanket; keep only fine lías, discard sludge
  6. 24–72 hours: Bio-integration — 1,800 L at 8°C, pH 3.25; gentle bâtonnage with inert gas
  7. Day 1–7: Sensory window — daily smell check; if ethyl acetate appears, abort and bottle
  8. Day 7: Tirage — rack off lías; add Liqueur de Tirage with EC1118; bottle

Five Levers of Control (this step)

  • Time: 7-day bio-integration (preferred under strict anaerobic control)
  • Temperature: <8°C acidification; 12–14°C aging begins after tirage
  • Oxygen: Master lever. CO₂ blanket for T2 transfer; crown cap; no splash; anaerobic tank
  • Extraction: None in assemblage; only gentle bâtonnage for lías suspension
  • Vessel: Stainless steel temperature-controlled tanks; sealed bottle

Assets

FilenameDescriptionStage
Adding 22pp Garnatxa to Trepat improves wineThe signature assemblage moment — 22% Garnatxa being addedAssemblage
elemination of skins from tankSkins removal (T2 selection)T2 sélection
fermentation processActive fermentationParallel
fermentation_process_ bubblesFermentation bubbles (CO₂ release)Parallel
transfusionRacking transferTriage
wine in tube_transfusionTransfer via tubingTriage
Trepat in the tank flowingTrepat into tankParallel
macerationMaceration / lías suspensionBio-integration
fermentation_with_clusters_on_topClusters on must surfacePre-press
Plot_of_fermentation processFermentation plotDocumentation
filterFilter mediaDocumentation
taking samplesSamplingMonitoring
taking_samples_microbiologyMicrobiology samplingMonitoring
Taking samples for microbiologyMicrobiology sampling videoMonitoring