Craftable supports a variety of Yield methods for you to use depending on the situation. Yields should primarily be applied at the recipe level, as that is typically the point at which you will be yielding the item. Craftable does however support an Item Yield as well, which can be used if your item is yielded before inventory - for instance if you trim the item upon receipt from your vendor, so only inventory the trimmed version. See below for a deep dive into these two different yield types, and more!
Item Yield can be set against the item itself, on the Item tab of the Item Panel. By default this is set to 100% and shouldn't be changed unless you trim or yield the item upon receipt of it from your vendor and before inventorying it. This is important to keep in mind because the application of an Item Yield less than 100% will have an impact on the CU Price of the item, which is how the item is valued on the platform.
For instance if you were to apply a 90% Item Yield to an item and you purchase 100lbs of the item for $100, upon receiving that item on an invoice the system would calculate that due to the Item Yield, the 100lbs only adds 90lbs to your inventory, and instead of each pound costing you $1, each pound costs you $1.11, as you really only got 90lbs, but still paid $100 for it.
As you can see from this example, while Item Yield has its use, if you are not trimming your item prior to inventorying it, then you should always keep your Item Yield (%) value set to 100.
Recipe Yield per Ingredient
Within each item in a recipe you can set a Yield % - this percentage will be applied to the RU Size (Recipe Unit Size). So if you add 8oz of an item to a recipe but apply a 90% yield, technically only 7.2oz of weight will be added to the overall weight of the recipe. This yield will not impact the cost of the ingredient in the recipe because the yield is applied after the amount of the item.
If the yield should be applied beforehand (e.g. I need the patty to be 8oz of beef after I lose 10% with my yield), then you should make my RU Size higher to compensate for the loss.
Recipe - Size Override
If you don't want to apply a yield against each individual ingredient in the recipe, you can also apply a size override to the total recipe, which will have a similar effect.
Craftable will attempt to calculate the total weight or volume of your recipe, and you will be able to see this calculation at the bottom right of the recipe, below the total cost. The system is only able to calculate this value when every ingredient in the recipe has a conversion for that method of measurement. So if all items are counted by a weight measure or have a weight conversion, then the recipe will display an auto-calculated total Weight. You can click the pencil icon to the left of this calculation to enter an override.
This override is quite useful so you don't have to necessarily enter a yield against each ingredient. If you know what the recipe produces in total you can leave your yields of each ingredient at 100%, and then enter an override size so that the system understands how much is yielded in total. This is especially useful if you plan to use the recipe as a subrecipe, the system will use that override size to calculate the amount that is required of each ingredient for depletion purposes.
Setting a Default Recipe Yield %
You can set a default "Recipe Yield (%)" against each item on the Recipes tab of the Item Panel. This setting does not change the item within any recipes, it just means that when you add the item as an ingredient in a recipe the Yield % within that recipe will default to this amount, but you can always change it. As mentioned above, recipe yield affects how much of the item remains after the recipe is cooked/prepared. It does not affect RU cost or how much goes into the recipe.