This is another thread I have wanted to reply to but have lacked the time. Very good questions from Donjim and very good answers as well
. The only thing I can do is reinforce the above.
For example, laserghost mentioned that, "things like evaporation can fluctuate greatly based on some variables." If you hang around here long enough and/or do enough brews, you will realise that, just like craft breweries, we homebrewers cannot expect repeatable numbers. Any brewer who claims to hit their numbers "bang on, every time", is not being dishonest but, most likely, unwittingly making exceptions and adjustments to match whatever their brewing software told them they would get. If they were able to hit their numbers bang on every time, they should run a commercial brewery because, even with their advanced equipment, large volumes, know grain specs and hop specs, they have to make adjustments on each and every batch.
Reading on home brewing, in so many places, will give you the perception/belief that all your batches should be repeatable. They shouldn't be.
For example, home brewers cannot control evaporation. The BIABacus gives a very good starting point and hopefully, in most cases, it will actually under-estimate your evaporation. We actually hope you will end up with less wort at a higher gravity than what you want. Why? Because then you can dilute that wort with some good water with no downside. If you have too much wort at the end of the boil at too low a gravity, there is no 'nice' way to fix that.
Furthermore, evaporation rates will vary massively from brew to brew. Imagine brewing outside in dry, hot, windy conditions compared to still, cold and humid conditions????
On your other excellent question re mash liquor to grain ratios, I have just googled the Mr Wizard question and totally disagree with the answer.
A lot of the writers of these articles (or on forums), like myself, are not brewing scientists, let alone have a science degree. The author of the article you mentioned actually does which is rare. But still, the answer displays a very poor knowledge of the practicalities and benefits of single vessel brewing. For example, it equates full volume brewing (simultaneous mash and sparge brewing) with 'no-sparge brewing,' which are two completely different things - see
here. There are several other things wrong or erroneous in that answer such as the mention of tannins.
ALthough I have seen the claim written, I personally don't know of or have seen a scientific basis of the claim that a thinner mash leads to a less attenuated wort. In fact, the only thing I have seen written on it is from Braukaiser. Braukaiser does great work but even these experiments, although they back up what I say, have not been repeated enough for their conclusions to be relied upon. As a matter of interet though, here's a screen shot from
this page.
2015-01-12_19-57-30.jpg
Whilst not a brewing scientist, I'll give myself a few things. I do research, read carefully and experiment as best as I can. I am also one of the few people that has the equipment to do do side by side, simultaneous brews. I do these as much as I can (not that often) and repeat them several times before I draw/make conclusions/claims...
Like laserghost and goulagain above, I usually do okay on comps when I enter them. One comment I have never had on any non-medal winner or medal winner is, "under-attenuated."
I must say that it's pretty annoying that magazines are writing answers like the one you have read Donjim. That answer will be quoted on forum after forum as being, "correct". The answer above will go unnoticed.
What a strange world
,
PP
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