The Brulosophy guys just did a mash temp experiment. It seems no one can tell the difference anyway so I wouldn't sweat it too much, you'll end up with beer.
http://brulosophy.com/2018/08/13/mash-temperature-147f-64c-vs-164-73c-exbeeriment-results/
Gah.
Sometimes I get a bit tired of the Brulosophy bit.
Sensory difference? Depends on a lot of factors as to whether you'll notice (both the beer and your palate).
Measurable difference with hydrometer? ABSOLUTELY noticeable. This has a direct impact on ABV as well.
Let me note at the outset that I think it's great the Brulosophy guys are trying to scientifically examine variables in beer brewing. I think they do a pretty good job controlling variables, too. I don't see a lot in how they do the experiments that is concerning.
However--and you knew there'd be a however--there are some major flaws in how they "test" the two beers. The biggest one IMO is that they have no control over what their tasters were eating and drinking just prior to the taste test. If a bunch of them have been drinking nice and hoppy and bitter IPAs just prior to testing, how accurate is their ability to distinguish flavors? Or a stout, say. And since these taste tests are often done at a bar or a taproom, it would appear to be almost guaranteed the participants have been doing exactly that.
Further, to do a triangle test properly, you need to rotate the order in which people are presented the beers. There are six possible orders in which the beers are presented: AAB, ABA, ABB, BAA, BAB, BBA. If you have, say, 30 tasters, then five should get the first order, five the second order, and so on. The reason is to eliminate ordering effects.
Third, though this is somewhat a weaker concern, we don't know to whom the sample of tasters generalizes. Are they people who like Pilsners? Or Stout-lovers all the way?
I don't want to make this too long, but I'm a scientist by training, and when you have alternative explanations for results, it calls into question the results. I take Brulosophy articles with a boulder of salt, because despite what appears to be a very good experimental approach to producing the beers in question, they leave open questions as to the testing methodology.
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I recently attended an off-flavor workshop put on by a local university--done in their food-science lab. During the workshop they did a triangle test with beer that had been light-struck and intentionally left in poor conditions versus some that hadn't. Commercial beer from the same 12-pack, so it was well-controlled on the production side.
The triangle test was presented to us where we had the three samples presented to us using the six orders (AAB, etc.) above. It was well-done, IMO. I asked specifically about using people who had successfully guessed which was the odd-one-out beer to judge which they liked better, and they said..."what?" The brulosophy people, when they do have a "significant" result, have those who guessed right evaluate which they like better--despite their candid admission they couldn't tell them apart. That also is an issue with how the Brulosophy people do their tests.
Again, bully for the Brulosophy people for trying to bring objectivity to all this. But we need to recognize there are serious limitations to what they do, and not place too great an emphasis on what they found.
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One last thing because I'm feeling wordy today. We have one experiment using a specific yeast and a particular style with a particular grain bill, using two mash temps that are pretty wildly different. I know why--you're trying to maximize differences if there are any to see if people can perceive them.
Would the results be different with a different style, yeast, mash temps, hops, malt bill, etc. etc.? I don't know. This is why, in the end, we need to test for ourselves and determine whether it matters to us.
