Off flavor from a partial mash

JaxBrew

Hi,
I wanted to know what kind of flavor an unconverted mash will impart to the finished beer.   I have an off flavor i cant describe and believe, through the failure of my thermometer that the mash never really got above 135.  I didnt do a starch test or check with a hydrometer, but later test showed my thermometer about 20 off.

Thanks
Chris

Denny

Well, it won't be sweet for one thing.  What type of grain were you mashing and for how long?  How much?