When I stained my hoses with coffee, the water was boiling and it had the same results. The hose came out much softer than it went in.I received my gauntlets today, which means I was able to get the correct size of braided vinyl hose from Home Depot and begin soaking them in coffee.
It will be interesting to see how long it takes for them to take the stain.
Something else I learned while test fitting the hoses to the gauntlets. The hose is slightly too small to fit over the tube coming out of the gauntlet. So, I used a heat gun to soften up about 3" of the vinyl to make it easier to install.
What I didn't expect was once the vinyl cooled, it remained very flexible. There must be some sort of breakdown that occurs by heating it.
I plan to do to this the entire hose once the coffee staining is done.