I'm going to argue with that, but at the same time "liking" the post for the rest of it's content. The grounds for disagreeing are based on some pretty extreme brewing though.
Preceding the post in question I had a post extolling the virtues of a "full boil mash". It added up to 7L/Kg and with just over 4Kg of grain (including 1Kg oat husk, 'cos half the total grain bill was rye malt) it was pretty near full for a Grainfather. The mash was 73C! The result was a "beer" of about 1.4% ABV yet a final gravity of about 1.016. Obviously in that case the final gravity achieved through mash temperatures was FAR, FAR, FAR, more important for flavour (mouth-feel at least) than anything else.
But the rest of his post did seem to support the use of "full boil mash" in my case.
You can do full boil mashes if you want? No body is going to stop you. These things are often about what pushes the overall outcome in what direction. The enzymes present will be more dilute and rapidly exposed to hot water. if this water is over conversion temperature they will quickly denature resulting in a less fermentable wort than a comparable thicker mash with the same temperature stand. There would be a minor difference in the beer. This is just one variable though. The starches present will indeed be super soluble, but in such an extreme case you'll still generally promote a less fermentable wort, varied by the total diastatic potential of your grist. Either way this is just another variable and again about pushing in an overall direction depending on goals. They contradict each other, but in certain scenarios they make a difference. It depends on what you are trying to do. It is more commonly like "I'm trying to make this beer finish high, so I'm going to mash hot, but not as hot as I usually would, because I'm also mashing thin due to it being a glucanous grist, lots of proteinous muck, I'm concerned about the run off ruining my life". You give it your best shot and then you move on to the next brew. Like I said though, 2.7-3L/kg as thin as will fit into the mash tun (within that range).
Your efficiency will be severally compromised by the lack of sparge. No sparge methods typically get 60% efficiency. Don't get me wrong, the high temperature is absolutely the main reason your brew finished at 16. The poor extract you experienced is because of no sparge. The thinner the mash, the shorter the sparge for a comparable volume.
For the heck of it we can work back from your brew. 1.4% abv is 10.68 points fermented. Add your final gravity of 16 ... starting gravity of 26.68. Assuming 3kg of malt as the husks have no extract 900 total potential extract, over 22 litres (assuming!) 40.9 potential at 100% efficiency, 26.68/40.9 ... 65.21% efficiency. Yeah par for the course assuming your batch size was 22L. 59% if it was 20 litres. If it works for you cool. I personally wouldn't even want to think about controlling mash pH, phenol extraction and other details in such a scenario.
What I mean about flavour and stuff is this ... if you are mashing outside of 64-68C without a very specific reason you are generally doing it wrong. This is with the caveat that I'm talking commercially. It is all about efficiency. If you want a higher or lower final gravity you don't mash outside of this range, you reach for another yeast or you alter your grist composition. Final gravity has an impact upon body, but you'd be REALLY REALLY REALLY surprised at how hard it is to detect differences in specific gravity. 1.100 is 10% denser than water. I meet people who claim to tell the difference between 1.001. This is a 0.1% difference in density and ... just complete rubbish. The amount of time lost where progress could be made because people hold on to these old ideas like "hmm, this brew is nice, but it could be a little higher in body and sweetness, lets increase the mash temperature by quarter of a degree next time" then they stand there and claim it is now perfection because it finished at 1.009 instead of 1.0088 or something similarly within the realm of a read error and they are drinking the wrong damn sample anyway.
Dextrins are flavourless carbohydrates. There is a little sweetness from them on the finish as the glycosidic enzymes in your saliva break them down into simpler sugars you can actually taste, but by themselves they taste like sand. They do lend body and a sensation of fullness, but again, you'd struggle to detect less than 7 points of them, sometimes 15. So many very popular (awful) commercial beers are super attenuated. Dextrins are an enemy of stability and sessionability because they make you feel full up (and fart). Mashing hot to the point where you have enough dextrins to make a beer thick and sweet is just ... banging your head against a brick wall, use a more flavourful base malt, reduce the carbonation, bias the beer towards chloride, add some sodium even, take out some of your bittering hop, think about some caramel or crystal malts, million ways to make it work, but no ... lets just increase the mash 0.25C when we brew it again sometime next year that'll do it I'm sure the ambient temperature won't throw it off anyway and the mash tun has a stable and homogenised temperature and our probes are calibrated and accurate to that degree, sure.
