On 2018-01-24, Andrew Gabriel wrote:

In article ,
Scott writes:

I thought biological detergents worked best at low temperatures?

The enzymes only work up to about 40C, after which they're destroyed.
The detergent in the powder will work hotter.
So, a modern machine (last 35 years) should fill at no more than 40C
anyway, and for a hot wash, it will crank the temperature up in stages.
There are other reasons too not to dunk clothes directly in 60 or 90
degree washes, but to work up to that in stages - some dirt which
is removable at lower temps will cook on at higher temps and be more
difficult to remove.

We had a hot-and-cold-fill machine until about 10 or 15 years ago.
Would it have filled with a mixture of hot and cold water even for the
60° or 90° programmes?