If you’re washing cottons or linens, always put the machine on a hot wash to make sure they’re hygienically cleaned.
Granny
Well. Back in Granny’s day (before biological washing powder), pretty much the only way to make sure something was hygienically clean was indeed to boil the damn things! However, science has come to the aid of the laundry: the modern biological washing powders use enzymes to attack and break up organic matter – and that process stops working if the enzymes get too hot (just as an egg won’t hatch once you’ve boiled it).
If you use a Bio washing powder, you’ll find it works best at around a 30oC wash. Happily, this is also a temperature that doesn’t need massive quantities of energy to get to so not only does the wash work better, it’s way cheaper – and there’s no chance of shrinking that synthetic-fibre garment that you forgot was mixed in the load. It’s a win-win!
Granted, there are times only a true hot wash will work: if you had a problem with bed bugs or clothes moth, for example, then a hot wash will kill the larvae and eggs without needing to use chemicals – but so would freezing them and, as an added benefit, there’s no risk of things shrinking because of the cold (stop giggling at the back, I’m talking about items like Cashmere or silks that simply won’t tolerate a boil wash).
Boil wash? Turn it down, Granny, this one’s definitely outdated!