South Africa Wine Technical Yearbook 2025

Contents

OENOLOGY

81

Authors / Contributors................................................................3 Foreword....................................................................................... 4 VITICULTURE 6 Winery wastewater irrigation (Part 1): Annual dynamics of volumes and quality at two wineries.....7 Winery wastewater irrigation (Part 2): Soil chemical responses on poorly drained soils....................14 Winery wastewater irrigation (Part 3): Soil chemical responses on a well-drained soil......................20 Winery wastewater irrigation (Part 4): Evaluation of a pot experiment on four differently textured soils...............................................................................27 Winery wastewater irrigation (Part 5): Effect on soil K, Na and pH (KCl) ................................................. 31 Winery wastewater irrigation (Part 6): Effect on soil phosphorus .......................................................... 38 Winery wastewater irrigation (Part 7): Effect on soil enzyme activities ................................................. 41 Winery wastewater irrigation (Part 8): Vulnerability of selected soils in areas with different rainfall .......................................................................... 46 Grape marc – a game-changer for greener dairies?..............53 The fascinating world of terroir in winemaking (Part 1): How nature, tradition and science come together ................. 55 The fascinating world of terroir in winemaking (Part 2): How nature, tradition and science come together ................. 58 Resistance of grapevine rootstocks to nematodes – the status quo in South Africa...................................................61 Near-real-time characterisation of vines ................................. 63 Rooted in research – what science says about regenerative viticulture. Part 1: Organic soil amendments, biostimulants and biological control agents...........................65 Rooted in research – what science says about regenerative viticulture. Part 2: Cover cropping and weed management.............................................................69 Rooted in research – what science says about regenerative viticulture. Part 3: Functional biodiversity enhancement.........................................................73 Soil texture’s influence on soil biological health indicators –implications for vineyard management.............77 Sunscreen for Sauvignon blanc................................................79

Cultural insights in wine aroma descriptions in South Africa, France and Portugal . ..................................... 82 OTR and long-term ageing of Sauvignon blanc wines..........84

Specific bioprotection against Brettanomyces : Naturally controlling Brettanomyces at the onset

of wine production with LEVEL 2 SALVA™............................ 87 Wine yeasts and energy saving in wineries............................94 Yeast-derived acidification of red wines .................................. 96 Q&A. Tackling calcium crystals in wine................................100 PRACTICAL IN THE VINEYARD 103 Post-harvest strategy for maximum reserve accumulation in grapevines....................................................104 Irrigation duration – time to give water... but how much is enough?.......................................................108 Profile pit stories with Johan ..................................................111 Watt’s up with row direction?.................................................115 Grapevine fanleaf virus............................................................117 Sunburn in the Paarl and Swartland regions........................119 Grapevine-associated Aspergilli .............................................122 PRACTICAL IN THE CELLAR 124 Tips to avoid the most common cellar mistakes (Part 1)...125 Tips to avoid the most common cellar mistakes (Part 2)...128 Guidelines for the management of barrel storage rooms....130 Post-harvest cleaning of equipment......................................132 Post-harvest reflection .............................................................134 Who is ultimately responsible for a task?.............................136 Checklists. .................................................................................138 New life ......................................................................................140 Benefits of ergonomics . ...........................................................142 GENERAL 144 Understanding CCC: South Africa’s trusted carbon footprint calculator for the fruit and wine industry.............145 Haygrove case study. Maximising sustainability: The synergy between SHERPA and CCC . ............................148

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TECHNICAL YEARBOOK 2025