Brewing is a simple process, we turn malted barley into fermentable wort. We then boil the wort to kill any nasties, while adding hops to add bitterness (aroma and flavour) and to preserve the brew. After that the yeast gets to do it's thing.
Pretty simple really
Why then do we get all worked up if our numbers aren't right? If our gravity is off or volumes down? Does it really matter? Surely we all still have beer at the end of it all?
When I first started brewing BIAB beers, I would stir the mash and check the temperature every 5 minutes. I would fuss and bother over efficiencies (whatever they are???) I'd worry over the IBU's the beer would have and all the while I didn't know what these things really were.
Now I don't touch the mash for 90 minutes and still get 80% post boil efficiency most brews. Some brews I only get 68-70%, but that's because I'm using a shitty bag of malt that just wont give me good extract conversion. But I know the malt is shitty, so I'm not bothered over the numbers.
I don't even bother taking hydrometer readings any more, ever, what's the point? I don't need to brag about getting such and such numbers and even if my extract efficiency is 10 points off, I still end up with beer at the end of the day that tastes the way it was planned to taste. I can't tell the difference between 2 identical beers with different eficiencies! They both taste the same.
What are IBU's? yes, yes I know International Bitterness Units, but what does that mean? I've brewed beers from 12 IBU's to 75 IBU's, sure 1 is less bitter than the other, but I could not drink a beer and say with any confidence that that beer is 42.7 IBU's. I could pick out hop bitterness, flavour and aroma, but that's where the limits of my palette end.
Sorry for the rant, but I get annoyed when, as brewers, we get hooked on and encourage others to worry about numbers that sometimes can't even be explained in a rational manner.
Beer is easy; Barley, water, hops and yeast.
Mash, mashout, boil and ferment.
It doesn't need to be any more complicated than that.
Thanks Hashie I'm not the only heretic here.I love reading everones input and ideas andI applaud the efforts of everyone sweating the details of the Biabacus.I still rely soley on The Calculator to give me a scaled grain bill and thats about it.I try to fill my kettle to the same rivet everytime and boil down to a mark on a stick.I like to eff around with different hop amounts and timings but don't really take much put much credence into IBU's.My multiple pages of notes have dwindled down to a record of grain weights,hop additions,mash temps and SG's.All other readings I take during the brew day are more from general interest and amusement.
.
Sorry.
, you can do that too.
) and a few rules of thumb, I make good beer!
. Hitting the numbers re-assures me that I'm doing great and that the beer would taste great 
. But I do dream of that hydrometer-less, number-less nirvana that only comes from experience... Now, shall I mash my next brew at 65.4C or 65.7C 
.
tell me it really isn't that important.