How a kosher run works
The model by which kosher wine is produced at ordinary European wineries.
Kosher wine requires no special grapes and no special technology. The requirement concerns people: from crushing until the bottle is sealed, the wine must be handled by Sabbath-observant Jews.
Hence the practical arrangement used across Europe. The estate halts its line, equipment is cleaned and kashered, a crew and a representative of the certifying body arrive, and the batch runs its full cycle in the crew's hands while the staff winemaker directs but does not touch the wine.
The constraints that set the economics: metal and plastic can be kashered, wood cannot, so barrels that held non-kosher wine are unusable and new ones are needed. Halting the line costs the estate time at the peak of the season. Small batches are therefore uneconomic; a kosher run starts to pay off from several thousand bottles.
Ingredients fall under the requirements too: fining agents such as gelatin, casein, isinglass and egg albumin must be kosher or be replaced by mineral and plant alternatives. For that reason wine composition is tracked separately in the registry.