water temperature in wash cycle

Question

Hi all, no fault to report , just water temperature up for discussion during wash cycle.

washing machine 2020 Series 5 Samsung 9kg front loader:

wash cycle: mixed 40'C

Time: 1hr 30mins

Weight: around 1/4 to half full drum

options: 'intense'

3 rinses

1000rpm spin speed

Cold fill only washing machine.

Incoming cold water mains temperature: 8.8'c

Time to reach temperature: over half an hour

Maximum Temperature achieved (40'c wash) : 38.0'c

time washing at around 38'c around 5 minutes before first rinse cycle

so there we have it - machine set to 40'c , and the washing machine only spent around 5 minutes actually washing at a temp of 38.0'c water. - make you wonder what is the point really if most of your washing is done with cold/lukewarm water anyway ... might as well just use a no heat wash??

amazingly the washing machine has a 15 minute quick wash (including wash, rinses and spin)  and you can select up to 40'c temperature!! - of course its not going to get anywhere near that temperature if it takes over half an hour just to heat water to 38'c .

In the old days of hot and cold fill I think at least you (if you had an immersion heater tank in the cupboard) the tank would heat up to around 60'c - the washing machine would have hot and cold fill water inlets . The machine would open hot solenoid and fill up the drum with hot water from the immersion tank - if got to hot (because remember if you are doing a 40'c wash you dont want the drum full of 60'c water) then the cold water  solenoid valve opened to let cold into the drum. - if needed the heating element inside the actual machine only cut in if the water in the drum was under 40'c (on a 40'c wash cycle) ... and then start washing (revolving drum , sloshing around clothes in 40'c temperature) from the start of the  wash! (and also dissolving the powder detergent because the water coming into the soap drawer was hot / lukewarm and not freezing cold mains water.

here was my little test set up using a digital thermometer :

38'c maximum temperature with 54 minutes left to finish cycle (wash including rinses & spin) - 5 minutes from reaching 38'c the drum emptied and then started going into its rinse cycle!!

I suppose our only saving grace these days (seeing as it seems most of the time you do your washing is in cold/lukewarm water until it reaches set  temperature of the wash cycle ) is that with the advancement of science etc a load of soap powders and liquids these days say (claim) on the front of the packaging that they get to work even at low temperatures (as low as 30'c or 15'c) bear in mind in the winter as its very cold outside that your mains water can be around 8'c and lower entering your washing machine drum, so it takes a bit of time to actually heat up to 15'c or 30'c.

I would love to hear other peoples views on this I have raised.  and also do people think that the washing machines these days should still be hot and cold fill instead of cold fill (even though apparently not an economical way of doing things) - did you find your older washing machines with Hot & Cold fill were better/better results at cleaning than these ones these days that just have cold fill?

Thank you for taking the time out to read.

Andy.

Whitegoodshelp · Accepted Answer

Hi Andy, my understanding is that modern detergents are designed to work most effectively when cold water is slowly heated to 40 degrees. This is definitely true for biological detergents, but may also be true for normal detergent. By the time the temperature reached 40 degrees, the laundry is clean.

This is why it's a bad idea to artificially add hot water to the wash cycle, as it will just cause the wash section to finish much earlier – before the laundry is properly clean.

Whitegoodshelp · Answer

When it comes to 60 degree wash cycles though, which are necessary for killing bacteria and germs,  some washing machines definitely fail

Some washing machines not getting to the right temperature

Whitegoodshelp · Answer

I wouldn't have thought it was that long,  but at least several minutes to be sure. If they can't survive at 60 degrees it's likely they would die quite quickly.

I think for the washing at 40 though the modern detergent starts working straight away and so probably doesn't need to be at 40 for long. They keep saying you can wash at 30  and even 20 degrees now.

Whitegoodshelp · Answer

I would expect so yes

andyr12345 · Answer

yes what is the official science , its not only that the water should be 60c and above to kill bacteria and germs, duration of the heat is also important isnt it?

Isnt it something like an hour or something like that at 60'c and above to kill them? - I think it is something like that.

andyr12345 · Answer

in the old days people used to boil re-usable nappys (cotton were they?) in 100'c boiling bubbling water to kill the germs and bacteria and get rid of stains... some machines only go up to 90'c these days if your lucky .

I suppose a mixture of eco / energy ratings / stop glass bowl shattering / stop people burning themselves on the glass bowl door / perishing rubber door gasket with high temperatures is the reason washing machines don't go up to 100'c these days like the old ones did?

Whitegoodshelp · Answer

Hi Andy. I don't remember any washing machines going up to 100°. The White's cottons temperature has always been 90°, at least since the 1960s. 90° is insanely hot, I doubt if many people use them any more but back in the 70s when I first started, many people routinely used the White's cottons wash cycle at 90° because everyone used cotton nappies.

I can definitely say that using the white cotton wash at 90° (which was often referred to as the boil wash) severely shorten the life of washing machines. Door seals used to last just 2 or 3 years, especially when they used that corrosive stuff called nappysan.

I've been doing a bit of research about killing viruses and germs since you wrote this article. And it seems that although some people seem to be a bit paranoid about it, I've seen where they said that tests have shown that just washing at 60° with good quality detergent is enough.

Speaking of which, I think you should do your test again but on the 60° cycle to see how it fares relating to the article I linked to which claimed that many washing machines either do not even reach 60°, or only wash at 60° for an extremely short time.

andyr12345 · Answer

Thanks Andy. I must be getting mixed up I thought the older hotpoint ones what I had in the 80's had 100'c on the dial. It must have been 90 or 95 then.

Yeah next 60'c wash I am planning to get the temp meter out again and see how long it takes to get to 60 and how long it washes for at 60.

I should imagine not much longer to get from 40'c to 60'c as it does from 9'c to 40'c? - in other words would water heat up quicker once its hot / warm rather than from stone cold?

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water temperature in wash cycle

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40°C wash only briefly reaches 38°C on Samsung Series 5 cold-fill machine

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