Best Wool Wash Detergent (A stain removal experiment)

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This is an experiment I have been wanting to run for ages. We are an outdoorsy family, with woollen jumpers, base layers, socks, hats and gloves to wash. And our children get messy! Wool wash detergents, being particularly gentle, are not always brilliant at dealing with stains. I wanted to know which wool wash was the best choice for washing woollen garments with marks and stains.

Best Wool Wash: the summary

The overall most effective product for removing stains was the Astonish Stain Remover Bar. This is also the cheapest option per wash.

The Astonish bar was the only stain-removal bar I could find which said it was safe for wool. I’m not a chemist so I can’t verify the ingredients, but I have been using the bar to spot-treat marks on woollen garments for four years without issues.

I would recommend pairing the Astonish bar with a wool detergent, using the Astonish bar to spot-treat stubborn marks.

Buy Astonish Stain Removal Bar on Amazon
The most effective wool-detergent in the experiment was good old Woolite. It performed nearly as well as the Astonish Bar, and was able to make a significant dent in the Sharpie marker I was using to label the sample! However, when used at the recommended dosage, it was the most expensive option. It also needed lots of rinsing, due to the amount of detergent being used.

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If you are looking for a budget option with good cleaning power, Ecover was the cheapest products per wash, and a mid range performer for stain removal. It put in a solid performance against mud, grass and greasy tomato stains. Ecover was only mildly scented and pleasant to use. It is also fairly easy to find in the shops.

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Now on to the detail:

Wool wash: how I tested the products

I tested Ecover, Eucalan, Nikwax, Soak and Woolite wool wash products. I also tested the Astonish stain removal bar.

For each detergent, I mixed up 1 litre of lukewarm water with the recommended product dose, and soaked the fabric for 15 minutes, gently rubbing at the marks at the beginning and end. I then rinsed the fabric 3 times in lukewarm water. For Eucalan and Soak, which are marketed as ‘no-rinse’ products, I tested them with and without rinsing for a fair comparison.

NB: a key feature of wool wash detergents is that they are gentle and do not damage the natural fibres of woollen fabrics. It is hard to test a detergent’s gentleness in a home kitchen! This experiment is primarily focussed on cleaning power.

Best wool wash product: detailed results

All the detergents were significantly more effective than plain water at cleaning the fabric samples. I decided to give each detergent a performance rating of 0-5 for each stain.

  • A rating of 0 meant the stain was no better than washing in plain water
  • A rating of 5 meant the stain was completely removed
Stained wool samples after washing: strawberry and blackberry were the most persistent stains

Here are the results:

Total ScoreSBMGCT
Eucalan (no rinse)11021242
Eucalan (3x rinse)14123242
Soak (no rinse)11111044
Soak (3x rinse)14123044
Astonish stain removal bar19224344
S = Strawberry, B = Blackberry, M = Mud, G = Grass, C = Hot Chocolate, T = Tomato Sauce

  • The Astonish bar and Woolite were the most effective products at removing stains. Both products were also able to significantly fade the Sharpie permanent marker I had used to label the samples, which was impressive! (The reason the top Astonish label is less faded is because I didn’t target that area with the bar)
  • All the wool wash products were significantly more effective than plain water. Both Soak and Eucalan were more effective when rinsed several times, compared to the ‘no-rinse’ sample, so I personally will continue to rinse with these products, even though they say it isn’t necessary.
  • Different detergents performed better at different stains. Soak was excellent at tackling the oily tomato sauce, but no good at grass. Nikwax or Ecover would be a better choice if you are washing a grass-stained cricket sweater, but didn’t make a dent in the strawberry stain.

Price is also a consideration here. There is quite a variety of price per wash between the different products:

Price per wash in GBP*Total Score
Ecover Delicate Laundry Liquid£0.1215
Eucalan (no rinse)£0.1711
Eucalan (3x rinse)£0.1714
Soak (no rinse)£0.2011
Soak (3x rinse)£0.2014
Astonish stain removal barunder 3p/wash19
*Price per wash calculated based on manufacturer’s recommended dosage in 5l/1 gallon, using a standard size bottle of detergent. ** I have been using the same Astonish bar for four years, it is about half used up and still effective.

Reviews of each detergent

Here are my thoughts on each product:

The Astonish bar was a clear winner for stain removal, performing as well as second-best Woolite in every category, and better against mud and strawberry. The Astonish bar is also exceptionally good value for money. It lasts for ages – my bar is still going strong after four years.

The Astonish bar is designed to be used for spot treating stains so you will need to pair it with a standard wool detergent.

Buy Astonish Stain Removal Bar on Amazon

Ingredients: The packaging states that it is suitable for use on most fabrics, including delicates, silk and wool. I looked over the list of ingredients, and could not identify any enzymes, but it does contain an optical brightener (Disodium distyrylbiphenyl disulfonate). I have been using an Astonish bar to treat stains on wool for four years without spotting any fabric damage, so I feel confident to recommend it.
Ecover Wool and Silk was in the middle of the performance range, and at a very reasonable price. It was particularly effective against mud and grass, and was able to fade the sharpie permanent marker. Ecover is scented, but only mildly, and it was pleasant to work with.

A great budget option, and quite readily available in supermarkets.

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Eucalan contains lanolin, which is a wax produced by sheep to protect their wool and make it water repellant. In large doses it is used for waterproofing wool nappy covers. It is great for conditioning wool, because that’s exactly what it does in nature!

Eucalan is marketed as a ‘no-rinse’ washing solution, but I found that it performed better against certain stains when it was rinsed three times. It still performed relatively poorly against tomato stains and grass.

Eucalan is also surprisingly cost effective because only a very small amount (one teaspoon/5L) is used in each wash. It felt very gentle to use, and although it was not a top-performer against stains, I would recommend it for washing very delicate wool products, such as lacey hand knits.

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Nikwax Wool Wash is specifically marketed for sports wool such as merino base layers, and say it is deodorising. Our experiment didn’t cover smells, so unfortunately we can’t verify that claim!

Nikwax Wool Wash was the second-best performing wool detergent after Woolite. It did well on the grass stain, and completely removing hot chocolate. However, Nikwax was relatively expensive, because of the high suggested dosage in each wash.

By Nikwax on Amazon
Soak is a delicates detergent, which comes in a range of pleasant scents. As with Eucalan, it is marketed as a no-rinse product, but I found that it performed better with rinsing.

A full size bottle of Soak is expensive, but only a teaspoon is needed per wash, so it lasts a very long time. If you just want to try Soak, you can buy a pack of travel sachets in different scents.

Soak made no difference to the grass stain compared to plain water, but it did do very well against greasy tomato sauce. Although not a top-performer against stains, it was my favourite product for ‘feel’ (which I know is quite subjective), and I would happily recommend it for blocking hand knits, or as a general wool wash paired with a spot stain remover like the Astonish bar.

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Woolite was the top performing wool detergent against stains, beaten only by the Astonish spot-treatment bar. It is quite striking to see how much it faded the permanent marker I was using to label the samples. It performed well across the board, and was particularly effective against grass and tomato.

I don’t particularly enjoy the ‘feel’ of Woolite, it is pink and slimy. This is exacerbated by the amount of detergent you are advised to use (twelve times as much as Soak and Eucalan!), and it requires lots of rinsing to remove most of the detergent.

That said, it is the detergent I am currently using as my main wool wash product for dirty jumpers, base layers, gloves etc. It is reliable and effective, and I have had no concerns about fabric damage. Many detergent products are marketed at a ludicrously high dosage, and I would like to experiment with reducing the Woolite dosage to see if it is still effective at a lower dose, as this would be more cost effective and require less rinsing.

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Wool wash experiment: the whole story

For those who like to know all the detail, this section contains the full background story of my wool wash experiment!

Wool wash experiment round 1: My first attempt was not a success! I purchased some pure wool woven fabric and carefully stained ten different pieces with a mix of stains: strawberry, mud, tomato passata, grass, olive oil and hot chocolate. The next day, I washed the fabric, starting with the ‘water only’ wash. Alas, nearly all the marks came out straight away!

This was no good – I couldn’t compare wool washes if I could clean the fabric without even needing detergent. I decided that the brand new fabric was probably coated, and I needed to try again with an older material.

Experiment round 2: I bought a second-hand cream lambswool sweater, cut it into sections, and hemmed the edges. I went through the staining process again, and tried to choose some more persistent stains! This time I went for:

  • Strawberry (S)
  • Blackberry (B)
  • Mud (M)
  • Grass (G)
  • Hot Chocolate (C)
  • Tomato – an oily pasta sauce (T)
Grass, mud, hot chocolate, strawberries, blackberries and tomato pasta sauce

These are all marks that my children tend to get on their clothes. This time I left the stains for 4 days to set (after all, I don’t always have time to get to wool wash items straight away), and then started washing with a ‘water only’ control. This time almost all the marks stayed in, with the most persistent being the strawberry, blackberry and tomato. Hurrah!

Unwashed control (left) and water-only (right)

For each detergent, I mixed up 1 litre of lukewarm water with the recommended product dose, and soaked the fabric for 15 minutes, gently rubbing at the marks at the beginning and end. I then rinsed the fabric 3 times in lukewarm water. For Eucalan and Soak, which are marketed as ‘no-rinse’ products, I tested them with and without rinsing for a fair comparison.

Future experiment ideas

  • I’d like to experiment with the dosage of the different detergents. For this experiment, I used the manufacturer’s recommended dose, which varied significantly from 5ml (1 teaspoon) in 5L for Soak and Eucalan, to 60ml for Woolite. Some of the higher dosages felt excessive, and required quite a lot of rinsing to shift. It would be great to know if the product could be used more sparingly.
  • I’d like to try soaking the fabric for a longer time. In this experiment, each sample was soaked for only 15 minutes and then rinsed. It’s best to minimise agitation when washing wool, and I wondered whether some of the detergents might need longer to get to work on stains.

Do you have a favourite wool wash product? Let me know in the comments section!

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