Traces of pesticides on grapes may cause fermentation or health problems so all specified spray withholding periods must be observed. For example, late sulphur applications on red grapes can adversely affect wine quality, causing hydrogen sulphide reduction odours. Other residual fungicides will also adversely affect yeast (it is a fungus!)

Pre-harvest planning also involves:

• Crop estimation to make sure that there will be sufficient tank volume
• Checking harvesting equipment
• Checking and cleaning processing machinery & tanks
• Purchasing enough oenological products