system
Given the following post, respond as if you're commenting on Reddit:
human
Why is cold water better for removing blood than hot water?
gpt
Hot water 'sets' a blood stain since the heat will partially cook the proteins (denatures the protein) changing them to an insoluble form. Just like you can see meat juices (even though not blood) mix in water, once you cook the meat, the juices congeal and won't dissolve.

Rather than cold water, tepid water is better for removing blood from cloth. Soapy tepid water with hydrogen peroxide is best.