Short ripening times raise the possibility of agrochemical residues if chemical withholding periods (WHP) are not met. The AWRI website has a large amount of information which may assist growers and winemakers alike with regard to potential issues. In particular, the maximum residue limits (MRL) are listed for 36 key export markets. These limits should be satisfied when the WHP recommendations in the ‘Dogbook’ are followed. If fruit is harvested earlier than expected and the recommended WHP has not been met, all is not lost.
The first step is to contact your grape purchaser or winery and let them know. It may be that the fruit is not destined for export or is going to countries that have an MRL equal to Australia’s. In this instance, the WHP you need to have met is the one on the label. To see the export market MRLs for chemicals registered in Australia, visit the AWRI website.
If the fruit is destined for a market that has a lower MRL than Australia, the only way to be sure that your wine meets the regulations is through residue testing. Testing can be done on fruit prior to harvest or post-fermentation. Post-fermentation measurements are usually (but not always) lower than that observed in the fruit. Testing grapes might be necessary as the results might influence how the fruit is managed in the winery however in many cases it is the residue in the final wine that counts and this is what is analysed.
The recommended WHPs are listed in the ‘Dogbook’ and this can be accessed on-line.
For further information on withholding periods or maximum residue limits, contact the AWRI by email or by telephone on: 08 8313 6600. The AWRI Commercial Services also offers residue testing on grapes and wine. Visit the AWRI Commercial Services website or contact the AWRI Commercial Services for further information by email or by telephone on: 08 8313 6600.