The four variables

In detail

Almost every practical question about cleaning is a question about four variables and how they substitute for one another: what chemistry is applied, at what temperature, with how much mechanical action, for how long. Reduce one and something else has to rise for the result to hold. That single idea answers a surprising number of things. A cool wash cleans as well as a hot one only because enzyme chemistry and longer cycle times were developed to replace the missing heat. A delicate fabric that cannot take agitation or temperature needs better chemistry and much more time, which is exactly what a long, cool, gentle programme provides. A soak works because time substitutes for the scrubbing that would damage the surface. And when something is not working, the variable people increase is almost always mechanical action, because it is the one under direct control — and it is the one most likely to damage the surface rather than the soil. The trade documents in this register say the same thing in their own words: work gently, be patient, allow the solution to remain a few minutes, repeat the same step rather than pressing harder.

Why

• Agitation is explained by The four variables
• Pre-treatment is explained by The four variables
• Hot-water extraction is explained by The four variables
• Machine washing is explained by The four variables
• Two-stage degreasing is explained by The four variables
• Soaking is explained by The four variables
• Defoamer is explained by The four variables