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  Mould In Washing Machines

Lately we have been receiving more and more reports of lumps of mould, slime, gunk or grime being deposited on laundry inside washing machines. In this article we will try to explain some reasons that we suspect this is on the increase, how to solve the problem and how it is related to smelly washing machines, foul odours and other things you really should know.

Zanussi washer dryer drum assemblyCertain machines appear to be more prone to this phenomena than others and, in our experience, it tends to be more of a problem on machines that have a plastic outer tank. To understand this there is a diagram of a typical modern washing machine's innards to the right, in this instance from a washer dryer by Zanussi picked at random.

What is shows is the inner drum, the stainless steel part sometimes referred to as a "basket", where you put your laundry shown as item 250 but this is full of holes to allow the water to flow in and, back out after the washing process. 

The part that we're referring to here is shown as item 150A as the rear outer tank or tub and item number 150, the front section of the tank. 

The outer tank or tub is the part surrounding the drum you put clothes into and holds the water used to wash the clothing in. This is what we're interested in.

  Plastic Versus Stainless Steel Tanks

The reality is that, we can't think of a smelly washing machine problem, mouldy lumps or gunk issue from a washing machine that has a stainless steel outer tank. Not a single one. And, we see a fair few washing machines.

We can't prove this beyond doubt of course and, we doubt anyone really could categorically prove it one way or the other due to the hugely wide variations in use, tank design, water, detergents used, laundry washed and so on but we're pretty sure based on a massive amount of experience with these issues.

Our theory is very, very simple and, usually, the most obvious and simplest explanation is correct.

Stainless steel is completely inert, exceptionally smooth, hypoallergenic and all of that, that's why we use it for cooking with, surgical procedures and so on. The fact that it's also highly recyclable is also nice, but that's another topic for another time and place.

It therefore makes a huge amount of sense to use stainless steel where you are putting in mucky clothing covered in goodness knows what, from skin grease, bed mites, food, excrement... you name it, even if you don't see it there's some of it in your washing. 

The thing is, not many washing machines now do have a stainless steel outer tank, most of them are plastic.

Washing machine rear tub section with bearingsPlastic is, by comparison to stainless steel, a rough surface. 

But, worse than that, in order to save on materials and weight a lot of plastic tanks have sections that are cut out of them as shown in the image, again picked totally at random.

What you can see there is that there are "splines" for want of a better way to describe it, that we think are just great big bacteria traps.

So, before we even kick a ball there's two major issues with a plastic tank. The fact that the surface is rough, more rough than stainless steel and the second is that we have these bacteria traps but, that's not the end of it. That's just the start of the problems.

  Low Temperature Washing

Loads of people these days are washing at lower and lower temperatures.

Without getting into a debate over how effective that is, even with the so-called low temperature detergents you can get these days, the fact is that low temperatures as in "cool" washes don't kill bugs and bacteria. Simple fact that most people, when they actually stop and think, completely understand.

So if you combine low temperature washing which isn't killing any bacteria with a plastic outer tank with a surface that the bugs can get a grip of and lovely nooks and crannies that they can breed in you can see why we think that these plastic outer tanks could be an issue and a major contribution to the problem of mould and bad smells.

The story isn't over yet though.

  Liquid Detergent And Washing Machines

Many people use liquid detergent, for some people that's all that they use. Completely oblivious to the fact that no liquid detergent can have any bleach in it at all.

The reason for this is that bleach is "heavy" and would sink to the bottom of the package so unless you shook it every time before use you would end up with a portion of concentrated bleach at the bottom of the pack. People won't shake it and clothes would get bleached, detergent manufacturers would get claims for damage and so, they just omit the bleach and then don't have the problem.

Instead there is "optical brighteners" in liquid detergents. 

There are no ingredients in a liquid detergent that provide any sanitisation whatsoever. None.

  The Net Effect

Mouldy washing machine that smells terribleIf you wash with liquid detergent only in a machine with a plastic outer tank, don't do any maintenance washes, leave the door closed on the washing machine all the time or don't clean it regularly with a cleaner like Affresh then you will almost without a single shadow of doubt have a washing machine that, inside, is caked with mould.

The image to the right shows a mild case.

This mould or gunk is bacteria, solid lumps of the stuff. Usually it will appear as black lumps of "gunk" after a wash or you see it as black spots on the laundry.

The black spots aren't an actual problem with the washing machine as it is doing exactly what was intended, it's just the side effects of use that are causing the issue.

You have to think however that you are actually washing your clothes or your children's clothing perhaps, in a solution that contains a mountain of bacteria and you probably don't even know it. It's really not a very pleasant thought at all made all the less pleasant when you see some of the cases we have.

When this is bad the smell can be so bad that you almost cannot tolerate being in the same room as the washing machine is. 

When we open up a machine that has this stuff in it you can quite literally be left retching as it is utterly, utterly disgusting and, people wash their clothing in it to get it clean!

To learn more about how to avoid this and a stinking washing machine full of bacteria you should also read Smelly Washing Machines, Brighter Whites and the Maintenance Wash articles.

  Cost Driven Washing Machine Culture

The obvious question to ask for most people is, "why don't they just make them all from stainless steel so we don't have this problem?".

Well, there is of course that in really extreme cases with no education that it could, possibly, perhaps happen in a washing machine that has a stainless steel outer tank but we doubt it.

No, the problem is cost. 

A stainless steel outer tank will add about £200 to the current price of a washing machine at the time of writing and, stainless steel is an expensive material to use. The fact of the matter is, some people think that they can buy a washing machine for less than £200 never mind pay that for just one element of the washing machine.

On balance however, most reasonable people understand this when it's explained to them and understand that a stainless steel outer tank in a washing machine for a lot of people, especially those washing for people with issues that mean soiled laundry or babies when you wash towel nappies, it's really not an option. But that is when people know, sadly most people don't.

Most people probably wouldn't even ask and just find out when they have a problem and find the likes of this article on the internet when trying to find a cure for the problem.

My washing machine isn't smelling (thankfully) but has been leaving brown deposits on the clothes. Initially it was just a few specs, so I did a maintenance wash. I then did a wool wash, but the clothes came out covered in far more bits of gunge than I'd seen before. I did another maintenance wash, brushed as much of the gunge off the clothes as I could and did another wool wash. The woollen items have just come out with more gunge on them than ever and I can see gunge on the inside of the washing machine drum. I've cleaned as much of it off as I can with kitchen paper and am thinking of doing another maintenance wash. Am I doing the right thing? I'm worried about the fact that there's far more gunge after the maintenance wash than there was before it. Will it eventually go if I keep doing maintenance washes? How many will it take, I wonder?
Kenneth Watt
Hi Clare,I am unaware of any integrated ones with a stainless inner drum these days.
clare prebble
Pleased can you recommend a washing machine with a steel drum, thank you. We have one at the moment which is Swedish but want to purchase an integrated machine.
Kenneth Watt
Hi jill,The temperature rises gradually and that allows the enzymes to work. Just as they would on a normal load with clothes in it.There is no definitive proof that the porous surfaces are causing the problem but lots of circumstantial evidence points in that direction.Affresh works well used correctly but, like any solution, it's more of a management for the problem than a once only permanent cure, which doesn't exist I'm afraid.I don't know what the active ingredient is, the formulation is not an open standard.
Jill Butler
Your advice on solving slimy gunk btween the drum & casing is to do a maintenance wash with a bio/ bleach containing washing powder.:-A hot wash will destroy the effect of any enzymes so how is that beneficial?Also I have been told that bleach is ineffective against moulds, (which I think are the main source of the problem as there is no smell), where they exist on a rough/porous surface, because it penetrates the surface and the moulds actually feed on the bleach . You imply that it is the rougher nature of the plastic outer casing that is the root cause of the problemDo products such as Affresh actually kill moulds?..(There are very few substances active against moulds)..What is the active ingredient? Is there a solution to the problem?

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