Grapes harvested from organically grown vines vary significantly from those harvested from conventionally or SWNZ grown vines. Organic vines compete with grasses for minerals and water because weeds and grasses are not killed using chemical herbicides. Vigour is naturally curbed, plants are less active at harvest time and therefore deliver lower yields and around two weeks later than conventionally grown grapes.
With Sauvignon Blanc for instance, the flavour profile at harvest is less pungent for various reasons.
Once harvested and in the winery, Organic Certification directs a low intervention regime that rejects using certain compounds routinely used in winemaking. Only organically certified products can be used, including yeasts and fining products
Additionally, fewer yeasts are admissible and sulphur levels (preservative) cannot exceed 100mg/L. Sulphur is used routinely in conventional winemaking as well as SWNZ. In the case of Sauvignon, the addition of sulphur at the harvester under these regimes captures and enhances the aromatics and protects the grapes from the trauma of the picking.
With limited yeasts available to capture a wider flavour spectrum and a lot of fining agents out of bounds, the organic winemakers’ toolbox is a lot more limited. In all cases, organic wine is a pure expression of the vineyard site and the handprint of the winemaker is much smaller. Winemakers have to be more careful, the flavours are more fragile and the thread of balance striven for in the vineyard needs to be retained. The wines are processed in a small Organically Certified Winery, developing at their own pace.