Sinner's circle describes the four factors that together determine the cleaning result: chemistry, mechanics, temperature and time. If you increase one factor, you can reduce another. Here is how the factors interact, concrete examples per task type, the limits you cannot go below — and the connection to cost and the Ecolabel's chemical reduction.
Introduction
Sinner's circle is a model for what determines the cleaning result. It is based on four factors: chemistry (the choice of cleaning agent and dosage), mechanics (the physical effort — scrubbing, rubbing, mopping), temperature (the heat of the working solution) and time (contact time). The model is often shown as a circle, where the four factors together make up 100% — if you increase one, you can typically reduce another. The model is attributed to chemical engineer Herbert Sinner (Henkel, 1959) and is also called TACT after the English words Time, Action, Chemical and Temperature.
The Four Factors
| Factor | What it means in practice |
|---|---|
| Chemistry | Cleaning agent, pH and dosage. Wrong dosage gives either too weak effect or unnecessary consumption. Follow the label. |
| Mechanics | Rubbing, scrubbing, rinsing — the physical energy you apply. Microfibre contributes mechanical scraping. |
| Temperature | A warmer working solution increases chemical reactivity and loosens grease faster. Be mindful of what the surface can withstand. |
| Time | Contact time: the longer a product is allowed to work, the easier the dirt loosens. Critical in disinfection (dwell time). |
How the factors affect each other
The factors are not independent. Temperature is the one that most clearly helps the others: warmer working solution makes grease more fluid and increases the reactivity of surfactants and chemicals, so dirt comes loose faster. Chemicals work via pH and surfactants (see the article on pH) — but more agent is not equal to better result once the lime is bound and the dirt is emulsified; overdosing just gives film and foam. Mechanics supply energy directly (scrubbing, microfibre's scraping), and time lets the chemicals work. If you cannot turn up one, you must up one or more of the others.
Cases: turn on the right factor
| Assignment | Turn UP | Screw DOWN |
|---|---|---|
| Burnt-on kitchen grease | Temperature + alkaline chemistry (degreasers) + a little time | Doesn't need violent mechanics if chemistry/heat is allowed to work |
| Lime on fixture/toilet | Acidic chemistry (descaler) + time | Mechanics and temperature are secondary — it's the acid that dissolves the lime |
| Daily dust and light dirt | Mechanics (microfibre) — often just water | Chemistry can be kept very low; no high temperature needed |
| Surface disinfection | Correct chemistry + fixed contact time | The time can NOT be shortened with more mechanics or heat |
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