for isopropyl alcohol it is best to use a quick wash method.
washing for more than a minute is gonna be pulling off lots of chlorphyl, plant sugars, waxes, etc.
washing for such a long time will have a very diluted product.
properly done Iso hash should end up getting real hard and shiney when evaporated properly but my guess is that when you evap this stuff that you will have a very waxy lookin feeling substance that doesnt shine.
it will still have THC in it but next time just wash it around and shake it up for 30-60 seconds and you will have a nice product
i know some people say to wash it for a couple minutes to get all the THC but from my experience the majority of the thc is absorbed in the first 30 seconds and only washing longer seems to get a small amount more THC and a lot more plant waxes, sugars, chlorophyl, etc.
a real good place to learn about hash is tokecity.com