The Orthodox Union receives many inquiries about certification of wine. This is a typical response, as written by Rabbi Nahum Rabinowitz, Senior Rabbinic Coordinator.
Thank you for your inquiry and interest in OU kosher certification. Please be advised that although the primary ingredient of wine — the grape — is inherently kosher, kosher wine and grape juice, due to kosher ritual requirements, are among the most kosher sensitive products. In the manufacturing process, subsequent to the point of grape delivery and pressing, all handling and processing is done exclusively by special kosher workers. This restriction remains in effect through the final bottling unless the product is sufficiently heated, such as in pasteurization.
In practical terms, kosher wine production entails having a team of kosher workers for the crushing phase and one kosher worker to be on call for sampling, modification, transfer and bottling of the product.
Depending on your location and the accessibility of kosher workers to the winery, the organization of such a program can be challenging. If you are interested in pursuing kosher certification, the first step would involve an evaluation of the facility at which time the details for your winery can be laid out.
Should you have further questions please do not hesitate to contact me.
Rabbi Nahum Rabinowitz
Senior Rabbinic Coordinator