Hot water is not a universal solution for stubborn stains. For some stains, it can worsen the result, but the claim that it “seals forever“ all stains is too general. The composition of the stain, the detergent and the instructions on the garment label are important.
Blood is among the stains that should not be started with hot water
Blood contains proteins, and high temperatures can fix them in textile fibers. The American Institute of Cleaning recommends soaking fresh stains in cold water and explicitly warns: “Do not use hot water, because it will set blood stains.“
After the pre-rinse, a stain remover or enzyme cleaner can be used. Protease enzymes are designed to break down protein stains such as blood and eggs. If the stain remains, the garment should not be tumble dried before being treated again.
Eggs, Dairy and Body Fluids
Egg, milk and cream stains also contain protein, but often have added fat. Therefore, pre-treatment is more important than choosing the highest temperature. According to the institute, enzyme preparations are particularly suitable for blood, body fluids, dairy and eggs.
This does not mean that every such stain can be removed with just a cold wash. After pre-treatment, follow the instructions on the detergent and the garment label. The temperature is selected according to the material, and not automatically at the maximum value.
In the case of ink and chocolate, the rule has important clarifications
Ink can spread if water is poured on it without rinsing first. The Good Housekeeping guide recommends rinsing with cold water first, then allowing soaking and washing in warmer water if the fabric allows it. This shows that hot water is not automatically prohibited for all ink stains.
Chocolate is also not entirely on the list of stains that hot water inevitably fixes. The American Institute of Cleaning recommends first removing excess chocolate, soaking the garment in cool water, and using a pre-treatment agent. It can then be washed at the highest temperature allowed for the fabric.
The biggest risk is the dryer
The general rule is to treat the stain as soon as possible and check the garment before drying it. The heat from the dryer can permanently set the residue if the stain is still visible. So the approach is simple: first identify the origin of the stain, then pre-treat, and then adjust the temperature according to the fabric and washing instructions.
Source: Good Housekeeping