Can selling a glass of wine deplete the right fraction of a bottle?
Find recipe ingredients in product inventory settings.
Recipes is the inventory setting for ingredient deductions. Its help text describes a quantity of another product's inventory to deduct per sale.
Open your sublocation from Locations, select Configure Products, and open the product's Inventory tab. Enable Track Inventory, then Recipes, to reveal Add ingredient product....
Select a tracked ingredient from Add ingredient product.... Products without stock tracking are labelled Inventory not tracked.
The ingredient row has a Qty: field, initially 1. It accepts decimal values such as 0.2 for the quantity to deduct per sale. Check how the ingredient’s inventory is measured before setting the quantity; the row does not provide a separate unit selector.
Select Create Product to save a new recipe product. To check its saved recipe, reopen More → Edit Product → Inventory.