I do single-infusion mashes in a converted cooler. Normally, I mash out with a relatively small amount out boiling water to bring the mash up to 180 F and then sparge. I'm doing an IPA with an OG way higher than I usually do (1.085) and the amount of boiling water needed to mash out approximately equals my sparge water. So my question is: how can I calculate the temperature my sparge water should be in order to get the drained grainbed up to 180? Thanks!