Detergent use fine tuning

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potatochips

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I have a laundry tub that sometimes I like to let my machines drain in to for fun. This allows me to see the rinsing ability of many different machines when the final rinse draining and spinning starts. One thing Ive noticed is theres a small amount of suds are left over! And this is after following the detergents instructions on how much to put in.

So, I've started to tune how much detergent I put in so that when the final drain/spin starts, theres not much suds action. So far, I need to use about half as much as instructed. The clothes still come out clean, and smell fresh.

So, thoughts? Is this excessive? Under-washing clothes? How do you feel about having suds in the rinse water? Waste of money or is this a moot thought?
 
'Which?' commented upon this decades ago (look in the vintage Which magazines, posted by Vacbear and Paulinroynton).

Which? said that detergent manufacturers were in the business to sell, so never follow the given dosage as gospel. Instead, reduce the amount to a point where acceptable cleaning is still achieved.

AEG used to comment about 'tensides' in the final rinse, in their Oko Lavamat frontloaders. The clothes were apparently still well rinsed.

Hoover once mentioned about reducing the detergent dosage in their New Wave machines. This was probably to help reduce the suds-lock of foam.
 
The softness/hardness of your water comes into play, as well. I've had mechanically softened water all my life--in other words, very soft--and dosages can be cut to almost half for most loads. My self-dosing 2015 Maytag front-loader delivered an amazingly parsimonious dose of liquid Tide Ultra Stain Release and results were pristine. I realized I'd been overdosing detergents for years.
 
I have been using a coffee scoop (two tbsp, I think) of detergent per load with excellent results. Hot water for whites and heavy colors. Warm water for delicate colors. I have a GE PFWS4600 front loader.
 
I watch (and feel the water for slipperiness) during the wash cycle and dose accordingly. This is more indicative of proper detergent concentration. While I don't want to see lasting foam in the sink, remember that the action of the drain pump is likely to over froth the water so it is likely you may some minor sudsing.
 
Suds

I found this when looking through Montpellier's top-loader instruction manual MTL6120W:

"- abundant foam: This is often due to the
anionic surfactants found in the
detergents which are hard to eliminate
from laundry.
In this case, do not re-rinse to eliminate
these effects: it will not help at all.
We suggest conducting a maintenance
wash using a proprietary cleaner."
 
From the same Montpellier manual

A cackhanded disclaimer:

"The manufacturer declines all
responsibility for any printing errors in
the booklet included with this product.
Moreover, it also reserves the right to
make any changes deemed useful to its
products without changing their essential
characteristics."

I am quite sure Which? would delight in tearing them to shreds, especially if duff information was given or important info was left out, which might lead to injury or damage.

They have a duty of care to supply a safe appliance with appropriate instructions. Errors and omissions should be corrected in swift fashion.
 
"- abundant foam: This is often due to the
anionic surfactants found in the
detergents which are hard to eliminate
from laundry.
In this case, do not re-rinse to eliminate
these effects: it will not help at all.
We suggest conducting a maintenance
wash using a proprietary cleaner."

Have found this to be true. After several rinses if froth is still visible best to leave well enough alone and move onto drying. Next time things are laundered use less (or nil) detergent as the residue will provide some cleaning action.

What the anionic surfactants need isn't rinsing to remove IMHO, but oils/something for them to work upon. That is what they are designed to do. It also explains why if one adds fabric softener or anything else with a oil/fat base the froth tends to go away.

Back when purchased first front loader (Malber) made the mistake of using a full (sample) packet of a new Tide liquid. It created froth for ages that simply wouldn't rinse away. Contacted service department as was instructed to remove washing, pour a small amount of olive or some other oil into tub, then restart washer for a full cycle. Suds at once cleared and that was an end to things. Today of course one uses a silicone based anti-foaming product, but the basics remain same.

If you read the "troubleshooting" pages for many front loaders sold today (including IIRC even Miele) where the question of "foam still visible in/after final rinse" comes up; advice given is that does not mean things have not been properly rinsed by machine, but the properties of certain detergents (liquids) cause the issue. If one does not wish to see such froth, it is recommended to switch to powders.
 
Assuming anionic surfactants 'stick' to the laundry even after rinsing, and no fabric conditioner is used in the final rinse, would the aforementioned surfactants impart a degree of protection to the fibres, allowing dirt and stains to be more easily repelled?

Or would the inherent surfactants attract even more dirt?

Or is it a bit of both?
 
Me mum was always grousing about how detergent mfg's would recommend way too much product, intimating that they were trying to rip off customers. We also were the only family I knew in the 1950's that had a front loader (Bendix) so she kept a sharp eye on over-sudsing.

I think the reason the mfg's recommend what can be an excess is not quite so negative, as it's difficult to know all the variables in advance: tub size, water volume, laundry weight, soil level, water hardness, type of soil, etc. So the detergent mfg's tend to err on the side of excess, so that they don't get more complaints that their product doesn't clean well enough.

That said, I also don't like to see suds in the final rinse. Sometimes I'll run four additional rinses for a finished load if there's a lot of excess suds. There is a point of no return, however, as some tap water may be heavy in foam causing components that will result in what looks like suds in the final rinse. Or, the machine may have excess detergent caked into its innards, and that can take a while to flush out.

Oh, and Mum used to refuse to go for the "free towel in every box" promotions. She said towel took up space that should be for detergent... She was from a frugal generation.
 
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