ISO 5703:1979

Overview

ISO 5703:1979 - "Equipment for vine cultivation and wine making - Grape presses - Methods of test" specifies standardized test methods for evaluating grape presses used in viticulture and wine making. It applies to both continuous and discontinuous (batch) presses and defines how to compare the technological, analytical and sensory quality of must or wine obtained from a press against a reference (standard) press. The standard includes procedural details, sampling rules and required test equipment, with supporting annexes (A–E) that provide an example overall evaluation, inspection sheets, vat sketches and an example hydraulic press description.

Key topics and requirements

• Scope and definitions: Terms such as load, yield, gross/net output, overall evaluation and specific energy consumption are defined for press testing.
• Test principle: Press performance is established by pressing paired samples (test press vs. reference standard press) and comparing volumes, compositions and sensory properties.
• Pressing programmes: Recommended extraction sequences for different grape types:
  • Whole grapes - staged extraction (e.g., first fractions at up to 400 kPa, subsequent fractions up to 600 kPa).
  • Fermented grapes and pomace - staged extractions (example: first fractions ~400 kPa, later up to 1 000 kPa).
  • Non-fermented/destalked/crushed grapes and soaked grapes - specific pressure steps and volumes are prescribed.
• Sampling and preparation: Requirements for representative samples, static draining (up to 30 min), and pre-test homogenization; washing of fruit to assess soil/contaminants.
• Analytical tests: Centrifuging (20 000 g, 30 min, 20 °C), turbidity, density, dry extract, total acidity, volatile acidity, reducing sugars, polyphenols, mineral content and other oenological analyses.
• Mechanical/electrical measurements: Power consumption, rotation speed, pressing pressures, pressing chamber volume, and time/chronometric records.
• Reporting and inspection: Use of inspection sheets (Annexes B and C), tables for direct comparison with the standard press, and an overall evaluation method (Annex A).

Applications

• Standardized evaluation of new or modified grape press designs (manufacturers and R&D).
• Comparative performance testing in oenological test stations and independent laboratories.
• Purchase specifications and acceptance testing for wineries, cooperatives and equipment buyers.
• Regulatory or certification testing where reproducible press performance metrics (yield, energy use, must quality) are required.

Who uses this standard

• Grape press manufacturers and designers
• Wine equipment test laboratories and oenology institutes
• Wineries and cooperatives specifying or validating press performance
• Technical inspectors and conformity assessment bodies

Related standards

• ISO 3835 (Equipment for vine cultivation and wine making - Vocabulary), referenced for terminology used in ISO 5703.

Keywords: ISO 5703, grape presses, methods of test, wine making equipment, press testing, continuous press, discontinuous press, inspection sheet, overall evaluation, oenological analysis.