This should be interesting

[Gymrat]

I forgot to vorlauf before taking running from my sparge. I didn't want all that grain in my boil so I tried bailing it out with my pitcher. Finally I gave up and dumped my entire first r unnings in with my batch spare. I think this is called decoction if I am not mistaking. I did vorlauf that and it is all currently running into my kettle.

[FedoraDave]

It'll definitely be beer.

I've taken to spending more time with my vorlauf, and even doing so on my sparges, which I hadn't done before. Too early to tell if it's going to have an impact on the final product, but I do think it makes the wort clearer to start with.

[Gymrat]

I have always vorlaufed my sparge. To me a batch sparge is like a second mash. I am not so much concerned about clearer beer as I am paranoid about tannins boiling out of the grain that sneaks into the boil

[FedoraDave]

Interesting perspective on the sparge. I think of it as rinsing the grains more completely, to make sure as much of the fermentable sugar as possible makes it to the wort. That's why I do two sparges. The second is very pale, but any color at all indicates something is coming out. It can't be a second mash, since the temperature of the sparge water stops the enzymatic action.

I've never perceived tannins getting into my beer, not even with the very light ones.

[Gymrat]

The purpose of the sparge is to rinse more extract out of the grain. However as I understand it, more conversion does occur during a batch sparge which would make it like a second mash. I have always done the Vorlauf on both as I am still dealing with a settling grain bed on both. I have never perceived any tannins in my beer either but I don't want there to be a first time. When you boil grain they leach out. The question is how much grain does it take to make them noticeable?

[FedoraDave]

Good question. All I can say is, there was no mention of tannins by either judge on the Pearly Pils I submitted, and that uses 11 pounds of grain per five gallon batch.

[BigPapaG]

So, my understanding is that it's not so much the mash or the amount of grains used...

Where you can get in trouble is with sparge temps over 170*F and wort pH changes due to the loss of buffering potential due to dilution.

The former is not as common as most people can control the sparge temp, and with batch sparging the temp is the wort temp.

The latter is a bit trickier... Here, the batch sparge has an advantage (over fly sparging) as the pH stays relatively consistent throughout most of the sparge as dilution is spread out throughout the sparge. (EDIT: I believe the Vorlauf process effectively aids the sparging without changing the pH of the wort.) When using water alone to (Edit: fly) sparge, dilution occurs quickly and the wort pH changes due to dilution (Edit: the wort runs off followed by the predominantly water sparge) which can quickly cause a release of tannins from the grain into the wort.

Here, controlling the pH is critical to preventing tannin extraction.

Hopefully others will chime in here but I believe the above are the most common problem areas re: tannin extraction.

[Gymrat]

I am not sure how the amount of grains used came into this. But you can also extract tannins by boiling grain. My whole thing is I don't know how much of it you would have to boil before it is detectable in a 5 gallon batch. So I have always done my best to leave nothing to chance. I have always thought the Vorlauf would be just as necessary after a batch sparge as it would after the initial mash because when I batch sparge, I pour more water into the grain, then I stir it to even out the temperature and swish out more sugars, both of which definitely disturb the bottom of the grain bed. Of course after that is disturbed there will be more grain that works it's way to my valve. So it always made sense to me to take the first half gallon of that and pour it back into the mash just like I do the original mash. And I have always had a handful of grain go into my pitcher when I do that. In my opinion it is impossible to keep every single grain from making it's way into the boil. But I try to avoid as many of them as I can.

[BigPapaG]

I am a big fan of Vorlauf and I agree, anytime the grain bed is disturbed it can/should be used to set the bed again!