Most ingredients scale linearly with a recipe: double the servings, double the amount. A few ingredients don't. Salt, leaveners, seasonings, and some fats can be too strong (or wasted) at full scale when you cook a larger batch. The per-ingredient scaling factor lets you set a multiplier on a single ingredient so it grows or shrinks less (or more) than the rest of the recipe when scaling.
What the Scale × field does
Each ingredient row in the recipe editor has a Scale × field. The default is 1, which means the ingredient scales the same as the recipe. Lower the number (e.g. 0.7) to make the ingredient scale more slowly. Raise it (e.g. 1.2) to make it scale faster.
When the recipe is scaled, each ingredient amount is calculated as:
base amount × recipe scaling factor × ingredient Scale ×
At the recipe's original yield (recipe scaling factor = 1), the Scale × field has no effect — the amount you see is the base amount. The factor only kicks in when the recipe is scaled up or down.
A worked example
A chili recipe yields 50 servings and calls for 2 tsp of salt. You want to make 100 servings. Without per-ingredient scaling, the calculator gives you 4 tsp of salt — but in your kitchen, 100 servings only needs about 2.8 tsp because flavor concentrates as you scale up.
Set the Scale × on the salt row to 0.7. Now when the recipe is scaled to 100 servings:
Other ingredients double (recipe factor 2× × ingredient factor 1 = 2×).
Salt grows by 1.4× instead (2× × 0.7 = 1.4), giving you 2.8 tsp.
When to use it
Salt and seasoning blends — flavor concentrates at larger batch sizes.
Leaveners (baking powder, baking soda, yeast) — large batches need proportionally less.
Strong spices like cayenne, garlic powder, or smoke flavoring.
Fats or liquids with carryover — some recipes need less added fat as batch volume increases.
Refer to Setting a Scaling Factor for step by step instructions.
Duplicates, edits, and republishes
Duplicating a recipe carries the Scale × values over.
Editing a published recipe and republishing carries the values over.
Removing the factor (or setting it back to 1) returns the ingredient to linear scaling.
Validation
The factor must be between 0 and 5. Values outside that range are rejected with an error so you can correct the entry.
See also: Scale & Print Recipe for how the scaling calculator works overall.