Both Winery Operations and Inventory processes will allow you to add costs after they have been completed.
Search for the stock item or wine via the Quick Search and view the relevant operation in the History tab.
Click Add Cost for the operation.
On the Add costs screen, enter the Cost item and set an appropriate Quantity and Unit cost to work out the total cost to be added. Double check the Effective date to save this cost as of.
Next head into the Cost Admin Console, accessed via Accounts > Costs admin and search for the item. You will see that the cost is linked directly to the selected operation.