Nachklärung

Nachklärung is a term used in winemaking for the phase of further clarification after the initial fermentation and/or primary clarification. It involves allowing the wine to rest so suspended particles, lees, proteins, and other turbidity-causing substances settle out by gravity, resulting in a clearer wine before bottling or additional processing.

Purpose and effects

The main aim of Nachklärung is to improve clarity and stability by reducing turbidity and the amount of sedimentable material in the wine. It can influence mouthfeel and aromatic perception by removing certain colloids. The extent of clarification depends on factors such as temperature, vessel geometry, and the composition of the wine. Nachklärung is typically performed before final filtration or bottling and may occur in stainless steel tanks, wooden casks, or other vessels.

Methods

- Gravity settling and racking: allow the wine to settle and then carefully transfer clear liquid away from the sediment (lees).

- Temperature management: cooler conditions can enhance settling in some wines.

- Fining agents: in some cases, gentle fining agents (for example, bentonite, gelatin, or other approved substances) may be used to help remove specific components; selection depends on wine style, regulatory constraints, and vegan or allergen considerations.

- Post-Nachklärung steps: after sufficient settling, the wine may undergo filtration or stabilization as part of final processing.

Relation to other processes

Nachklärung is distinct from primary clarification and from filtration or stabilization steps, though it often precedes them. It is one stage within the broader set of clarification practices used to achieve a stable, marketable wine with desired clarity.

Limitations and notes

Over-clearing can strip some aroma and body, and not all compounds are removed during Nachklärung. Choices regarding fining agents and processing aim to balance clarity with sensory quality.