Might have mashed at 140*

So the other day I brewed a Scottish 80 and everything went well until afterwards when we discovered that the digital thermometer was reading about 10-15* higher than it should. This leads me to think that while I thought I hit my mash temps I may not have and actually may have been somewhere from 140-145* instead of 156*.

If it ferments out insanely thin due to the low mash temps is there anything I can do to add body back. Something like lactose or maltodexetrin? Anyone have any experience with this.

You could boil some water and a pound of lactose to try to add a little body and residual sweetness. I'd taste it first to see if it's really needed.

On another note, if you keg you could monitor your fermentation and cold crash when it hits your desired FG.

i've read that many commercial liquid malt extracts are prepared by mashing in the upper 150s. perhaps you can boil a pound or two and add to your beer.