Results from the first vorlauf xBmt showed us the method seemed to have little impact on distinguishability. Curious just what it would take to produce a difference, we designed an xBmt to test the limits, adding over 8x the amount of grain a typical vorlauf filters out to one boil and comparing it to the same beer made with a normal vorlauf. Results are in!
Vorläufig I’m not going to drop this procedure. Is anybody?
I’ve passed on it many times and haven’t noticed a lick of difference. It’s not every intentional, I just sometimes forget. When I’m using a BIAB bag in my MLT, I skip the vorlauf on purpose because the bag doesn’t allow any grain through at all anyway.
Nope. Its easy and kinda fun. I just won’t sweat it when I forget.
With a pump, it is pretty easy to do when you go to mash out temps. I will still do it.
Astringency is increased by decocting, but not enough to be objectionable.
What effect did you expect it to have with the pH in range?
It takes a lot of effort (or ignorance) to mess up a beer. Try it sometime.
On the homebrew level I do not think it is as important but on commercial systems it does become important or you will have a lot of grain and lipids from the mash pulled into boil kettle.
Was that for me? I have messed up plenty of beer in many ways. That means the beer did not meet my standards. It was drinkable,yes, but outstanding, no. Making beer is a forgiving process, up to a point.
The comments on astringency while decocting are from reading a lot over the last many years, and going to a few talks on it at the NHC. As to decoctions, we do at least a couple a year, sometimes more.
Some pros and cons from AJ Delange, who pretty much only brews Czech Pilsners.
http://hbd.org/brewery/library/DecoctProCon.html
Totally agree.
No. I was replying to the OP, who checked his pH during the process and then expected different results by purposefully adding grain to the boil. In range pH makes the whole tannin/astringency thing a lesser or non issue.
This is a really good example of why the results to any individual experiment have to be read narrowly within the confines of the experiment. Here the statistical analysis shows no discernible difference between the vorlauf and non-vorlauf batches, which suggests a vorlauf is not necessary but the author’s own tastings show the beers were blatantly different until a new factor (lagering) was applied. Had the tasting panel been assembled when the author would have preferred to start drinking the beers it seems any tasting panel would have overwhelmingly identified the difference. So at a minimum those results have to be read within that context.
We should also read those results to suggest that without an effective vorlauf one must fine and lager the beer to clear the excess tannins and other grain matter, which may be undesirable for certain styles and perhaps unavailable to many homebrewers who bottle.
Yes, it might be different with an AIPA or a heff that gets consumed fresher and without the extra process.
OK, thanks.
I have gotten very different results from the xbmts when I’ve not strained the husk materials properly. This has happened to me more than once. Maybe it doesn’t happen all the time, but when it does, it comes through as a sharp astringency. Part of this could also be an alkalinity / mash pH problem. In those past batches, I probably wasn’t as anal about pH as I am today (and still am not terribly anal, but am more now than the past).
If you really want to prove or disprove the notion of vorlauf preventing astringency, try this with a stout sometime. If you don’t do that magical thing where the roasted malts are added only at the very end of the mash, and mash the whole grist together for an hour or whatever, and then don’t bother to vorlauf at all… you could very likely end up with astringency. Black malt husks are not kind when boiled in my experience. And you might think the opposite would be true, that a light color beer would have higher pH and end up with more astringency. And you might be right, maybe. But I do know I’ve had problems with doing a crappy vorlauf with black beers. So, anyway. I’m not convinced that this is never an issue. Still pays to vorlauf IMHO. I even do it for my BIAB beers. I don’t want all that crap in my boil. I strain it out, whether it’s necessary or not. It’s so easy and not worth the risk not to IMHO.
Vorlauf effect part 1 showed a massive difference in clarity. That’s a good enough reason for me as I don’t usually fine (no space for fridge).
However I like the sound of a grain bag inside the mash tun if it achieves the same result as tediously trickling wort back in over a spoon while worrying about disturbing the grain bed.
Good reason to batch sparge. Vorlauf takes me less than a minute.
I like my hot scotchies to be clear and grain free. I’ll continue to vorlauf. 
My experience is that pre-lagering the astringency IS enough to be objectionable; post-lagering it is no longer objectionable (or even discernible for that matter). One experience I had that illustrated how much astringency can be produced in decoction mashing was a traditional, triple-decocted bock I did - prior to this I would not have thought this was possible.
After kegging the bock and carbonating over a few days, I pulled a sample and was heart-broken at the astringent quality that kicked me in the face - so much so that I almost dumped the batch there and then because there was no way this one would ever clean up (or so I thought). However, since I had plenty of empty kegs and batches that could precede this one, I decided to let it lager for many weeks (eight if I recall correctly) at ~38-40F. After the lagering period, I pulled another sample and it was 180° turnaround! No astringency, and a classic traditional bock character. After experiencing this turnaround it flashed me back to something Noonan wrote about in New Brewing Lager Beer which basically said exactly that: Lagering will precipitate the astringency in lagers as part of the process (or something like that).
As I understand it, the polyphenols bond to proteins which drop out during lagering.
It takes me a few minutes to pour back in gently but doesn’t add any time as the tap is open anyway.
Yesterday I tried opening the tap fully after vorlaufing - sonething I’ve never tried before, having read somewhere that you need to drain a litre a minute - and got nice clear wort. That’s a few more minutes shaved off the brew day.