[flbrewer]

Is there any truth to the fact that vorlauf should take X amount of time?

Is there any timing requirements to the speed of adding water back into the mash while sparging?

[S. cerevisiae]

Is there any truth to the fact that vorlauf should take X amount of time?

Is there any timing requirements to the speed of adding water back into the mash while sparging?

Actually, what you are doing when draining the tun is called "lautering."  That's why the combined use device in which you mash is called a mash/lauter tun. Most brewers used to refer to the step as lautering until there was a need to distinguish the technique that a brewer was using to separate the sweet wort from the grain (yes, there was a time when most all-grain home brewers continuous sparged). 

There is really only one type of sparging because the word "sparge" is derived from the Latin word for sprinkle (i.e., sparging does not technically occur until water is emitted from the sparge arm).  The batch sparging process is more accurately defined as multiple-infusion lautering because the first runnings are lautered followed by one or more hot water infusion/lautering steps.  It's a modern twist on a old technique known as "parti-gyle brewing;" however, with parti-gyle brewing each runoff was usually used to make a different beer, not combined into an "entire gyle," as occurs in batch sparging.

[brewday]

Is there any truth to the fact that vorlauf should take X amount of time?

Is there any timing requirements to the speed of adding water back into the mash while sparging?

I spend around 20 seconds vorlaufing, and about 2 seconds dumping the sparge water into the cooler.

[S. cerevisiae]

I realized that I did not answer your question after I hit the "post" button.  The purpose of the vorlauf is to settle the grain bed and recirculate to the top of the bed any fine particles that made their way to the bottom of the tun during mash-in.  Hence, you want avoid disturbing the grain bed when pouring the runoff back into the tun.  I use a pitcher and 4-cup measuring cup when recirculating.  I collect the runoff in the pitcher and gently pour into the measuring cup,  which I use to gently return the runoff to the tun.  I do so because I use a round tun with a relatively small diameter, and collecting runoff one quart at a time is a pain in the backside.   

[brewday]

I realized that I did not answer your question after I hit the "post" button.  The purpose of the vorlauf is to settle the grain bed and recirculate to the top of the bed any fine particles that made their way to the bottom of the tun during mash-in.  Hence, you want avoid disturbing the grain bed when pouring the runoff back into the tun.  I use a pitcher and 4-cup measuring cup when recirculating.  I collect the runoff in the pitcher and gently pour into the measuring cup,  which I use to gently return the runoff to the tun.  I do so because I use a round tun with a relatively small diameter, and collecting runoff one quart at a time is a pain in the backside.

That's correct for your fly sparging, but for his (and my) "multi-infusion lautering" we can just dump in the sparge water, give it a stir, reset the bed via another vorlauf, then drain away.

[brewday]

...Or at least that's the case for me - I use a braid.  I think he uses a false bottom, don't know if that makes a difference.

[S. cerevisiae]

That's correct for your fly sparging, but for his (and my) "multi-infusion lautering" we can just dump in the sparge water, give it a stir, reset the bed via another vorlauf, then drain away.

The vorlauf process is lautering technique agnostic.  What I explained in the text that you quoted is how I vorlauf, not how I sparge.

[brewday]

What I explained in the text that you quoted is how I vorlauf, not how I sparge.

You're correct - I read through it too quickly.  I just don't think it's necessary to avoid disturbing the grain bed when batch/infusion sparging.  Fly sparging?  Absolutely.

[hopfenundmalz]

Vorlauf translates to pre run, or fore running. You run a some out until the mash filter sets and the wort is clear.

[Black Sands Brewery & Supply]

Is there any truth to the fact that vorlauf should take X amount of time?

Is there any timing requirements to the speed of adding water back into the mash while sparging?

An exact time? Not really.  We usually recirc the mash for 5-10 mins until its starting to run pretty clear sometimes that takes longer. Then we begin to run off into the kettle. We start the sparge once the water level in the mash tun is about 1" above the mash bed and we keep adding water to match the flow rate to keep it around 1" above the mash.

Not the only way to do it just the way we do it.

[denny]

Is there any truth to the fact that vorlauf should take X amount of time?

Is there any timing requirements to the speed of adding water back into the mash while sparging?

No and no.  And probably what you've heard referred to relates to fly sparging.