Filling In Ingredient Concentration Ranges for Soap

Cold process soap makers hit a specific wall when they get to the concentration field on the Cosmetic Notification Form, because soap doesn't behave like a lotion where you weigh out 2.5% of an active and it stays 2.5% every batch. Your olive oil percentage might shift half a point between batches depending on how you scaled the recipe, your lye discount changes the free alkalinity, and your superfat is a range by design, not a fixed number. The CNF actually anticipates this. Ingredients can be listed by INCI name with a concentration or a concentration range, and for soap, the range is usually the honest answer.

Why a single number is often wrong for soap

Saponification isn't a precise stoichiometric event in the way a lab synthesis is. You calculate your lye amount against a saponification value for each oil, but those values are themselves ranges published by suppliers, oils vary batch to batch in their fatty acid profile, and most soap makers build in an intentional superfat, meaning some percentage of oil is left deliberately unreacted. That unreacted oil isn't a fixed quantity either.

So when you're filling in Sodium Cocoate, Sodium Olivate, or Sodium Tallowate on your CNF, giving an exact single percentage implies a precision that doesn't exist in the actual bar. A range that reflects your normal batch-to-batch variation is more accurate and, frankly, easier to defend if anyone ever asks how you arrived at the number.

Working out a reasonable range

Start from your base recipe as formulated, then think about the realistic spread across your normal production runs.

• Base oils and their sodium/potassium salts: calculate the theoretical yield from your recipe's oil weights and saponification values, then build in a few percentage points of range to cover normal batch variation and superfat adjustments.
• Unreacted superfat oil: if you superfat at 5%, but you sometimes run 3% and sometimes 8% depending on the recipe, your range should span that, not just your most common setting.
• Water content: this drops during cure, so decide whether you're filing based on fresh-poured or cured weight, and be consistent about which one you're using across your whole lineup.
• Additives like clays, oats, or exfoliants: these are usually more consistent since they're measured by weight against a fixed batch size, so a tighter range or even a single value may be appropriate.

A sample layout

Ingredient (INCI)	Typical role	Reasonable range to file
Sodium Olivate	Cleansing base from olive oil	e.g., 20-28%
Sodium Cocoate	Lather/cleansing from coconut oil	e.g., 15-22%
Aqua	Solvent/carrier	e.g., 30-38%
Glycerin	Humectant (natural saponification byproduct)	e.g., 4-9%
Kaolin	Additive, slip and mild exfoliation	e.g., 1-3%

These numbers are illustrative only. Your actual ranges depend entirely on your specific recipe, oils, and process, so run your own saponification calculations rather than borrowing someone else's table.

Keeping ranges honest without making them meaningless

There's a temptation to file an enormous range, like 5 to 40%, just to avoid ever being wrong. Resist that. A range so wide it covers every possible formulation isn't really telling anyone anything useful, and it undercuts the point of the disclosure. Aim for a range that reflects your actual recorded batches, pulled from your real production notes rather than a worst-case guess.

If you keep batch records, and you should regardless of filing requirements, go back through a handful of recent batches and use the actual spread you find. That gives you a defensible, evidence-based range instead of a number invented at the kitchen table the night before you sit down to file.

When to redo the range

An amendment is warranted whenever your formula changes meaningfully, not just when you change the final scent. If you switch a base oil supplier and your saponification value shifts, or you change your standard superfat target, revisit the range rather than assuming the old filing still covers the new normal.

Cosmetic Comply can help here by letting you duplicate a past filing when you're launching a close variant, so you're adjusting an existing range rather than rebuilding the whole percentage breakdown from scratch every time a new scent joins the lineup. For anything genuinely uncertain in your specific recipe, cross-check against Health Canada's current CNF guidance rather than relying on habit alone.