How we test laundry stain removers (soakers)

Overall score breakdown

The overall score is made up of 10 individual scores – one for each of the following stains:

• sweat
• groundnut oil to simulate collar and cuff grime
• make-up
• olive oil
• tomato
• ice-cream (chocolate)
• baby food (banana and strawberry)
• grass and mud
• blood
• mineral oil.

We use specially stained fabric swatches – four swatches of each stain for each laundry soaker we test. These swatches are used by detergent companies and consumer organisations worldwide.

We use the dosing tool supplied with each product (usually a scoop or the product’s lid) to measure a single dose of the powder or gel in accordance with the product’s directions. Where a range is given (e.g. 1–2 scoops), we use the higher (i.e. 2 scoops).

We record the weight of the dose, and we later use this information to work out the number of doses per pack plus the cost per dose.

For each stained swatch, we fill a bucket with 7L of water at 40°C, then stir in the measured dose until dissolved. We submerge the fabric swatch and leave to soak for 2 hours.

After 2 hours, we remove the swatch, squeeze out excess liquid, and wash in a front loader machine on a normal cold wash cycle with a mid-performing laundry detergent.

Following the wash cycle, we assess how well the stains have been removed. Our test scores are an indication of each product’s performance relative to the other products in the test.

In addition, we record what’s printed on each product’s label, including ingredients, garment suitability, whether stated to be septic system safe, grey water safe, biodegradable, antibacterial, and any other label claims.

Cold vs warm water

We soaked all stains in water of the same temperature (40°C, which is very warm), consistent with the directions printed on the majority of the laundry soakers’ packaging. But cold water is more effective for certain stains. In particular, we’d expect better results for blood stains soaked in cold water.