Here's what I do that works so well I've not yet had a problem hitting my temps for my Pumpkin ales. Sometime before my pumpkin is done baking I rinse off my rice hulls in my mash tun with the hottest water my faucet provides (about 130F) two times. On the third fill (which will be the third rinse) I add in boiling water until the water and rice hulls are at my mash temp (ie. my mash tun preheat temp) and let it sit sealed. I pull the pumpkin out of the oven and stir it up to help cool it a little more then re-spread it out in the pan. I check the pumpkin temp occasionally and once it's right about my mash temp I drain the water from the mash tun and scoop in the pumpkin, then add the strike water, then my grains.
I always keep a tea kettle with boiling water handy in case I need to adjust temp up but so far I've never needed it doing it this way. You can rinse the rice hulls less times if you want, I just prefer to do three rinses since they clearly aren't too clean.
Rev.
