Reading a bunch of threads on here, as well as looking back at some of the books I've got ( Palmer, Papazian ), I think I know the answer to my question, but looking for some additional input.
Last brew I made was an IPA. It's my 4th All Grain brew, with several extract and partial mash brews before that.
I've been working to get my consistency and efficiency better. I did much better this batch, hitting 1.062 (65%) of an optimal 1.068 (70%) OG. ( Measured with refractometer )
My error comes from a faulty thermometer. It's reading about 5 degrees too low. Even with that, I was on the high side of my mash temps. Planned was 154, dropping to 152 over the ~60 minutes. First temp reading after adding my strike water and mashing in was 158 ( which was actually closer to 163 thanks to the thermometer ). Let it go for ~60 min, and it was still at 155 after the hour.
Everything else went well, and I pitched with US-05 yeast and it's been fermenting for about 3 weeks at about 64F. Took my first reading at 2 weeks, and then every other day since. It's been solid at 1.022 for the past week. It should have finished up around 1.012-1.016 or so, according to the calculations. Would the overly high mash temps result in enough unfermentable product to lead to that high of a FG?
I'm thinking that's all I'm going to get, as due to the high mash temps, I created more unfermentable wort than normal. It's still tastes good, nice hoppy flavor, good malt to balance it, and has a bit fuller mouthfeel. It's definitely a very drinkable beer. Maybe not quite as high ABV as the plan, but still very adequate (5.5% vs 6.1%).
Next brew-day, have a new thermoworks digital thermo, and won't hesitate to add some cooler water, if I overshoot again on my strike water.
Any other thoughts, or similar experiences from anyone else?