Another mash circulation question

Hey folks!  I've posted this same question on AHA forum, but I figured I'd widen the search area.

I wasn't able to find an answer to this with Google or elsewhere in this forum and others, so here I am.

Recently, I saw a video where a professional brewer started recirculating through the HERMS system BEFORE mashing in.  IE:

1. Heated water to just above mash-in temp in HLT
2. Moved strike water to empty MLT
3. Began circulating water through HERMS at mash-in temp
4. Added grain (mash-in)
5. Continued circulating through HERMS until moving to boil kettle

Has anyone else done this on the homebrew scale?  I have been fighting my RIMS system a bit with getting a good grain bed, as the grain bed doesn't really stratify well - I get A LOT of flour through the pump, and the grain bed gets shallow about the edges of the MLT.

It seems like this method of running through the HERMS (or, RIMS in my case) could help keep the grain bed very consistent as grain is added to the MLT.

Thoughts?

I do a LOT of not-too-vigorous stirring during mash-in, and need the space where my sparge return manifold rests to do this. Not a consideration for my set-up.

If one didn't have the physical constraint I do, it seems like an interesting way to keep temps more consistent ... but would it make any perceivable difference in the final beer taste?

I didn't know there was a different way to mash.

richardk said:

Recently, I saw a video where a professional brewer started recirculating through the HERMS system BEFORE mashing in. 
...
I have been fighting my RIMS system a bit with getting a good grain bed, as the grain bed doesn't really stratify well - I get A LOT of flour through the pump, and the grain bed gets shallow about the edges of the MLT.
...
It seems like this method of running through the HERMS (or, RIMS in my case) could help keep the grain bed very consistent as grain is added to the MLT.

Click to expand...

Due to the grain and water weight in pro brewing, methods get adapted for a few typical reasons: time, heat, and/or efficiency. There are other reasons that are usually specific to the brewer or brewhouse, but these three are the most common.

If it actually is a HERMs of some sort, the brewer is taking into account the temperatures needed for the amount of heat s/he has. A typical pro brewhouse doesn't have the collective btu per gallon that a homebrewing rig will. So, if the brewer wants a profile step mans, s/he will start that process so that the grain rolls through a temperature range in a certain amount of time and thus the total mash time isn't hours and hours long.

Another reason may be that the vourloff is complete at the same time as conversion and teh brewer can go directly to runoff. One of the first breweries I worked at, the brewer said he had a "five step" mash process. Step 1, dough in, then down the three brewhouse steps and step 5: start the recirculation.

When you're getting uneven flow and stratification through the grain bed, it is the wort velocity through the grain that's causing the problem. Grain bed area is inversely proportional to wort velocity. Wort velocity is measured in column inches, not gpm. It's related to compaction of the grain bed by the difference between the velocity through the grain bed and the area under the grain because the velocity is a measure of force on the grain. You generally want to have as little force on the grain as possible or the effects you're observing are the result. In short, slow down your recirculation.

So, in both the pro's case and yours, the start of recirculation much earlier should accomplish two important things. First, you will get at least one complete recirculation of all your mash water, which increases extraction (hopefully speeds conversion if it's not too thin). Second, sets the grain bed gently, allowing you to move all the fines tot he top of the grain bed, without compaction.

In the pro's case, s/he may be adding heat to the mash to also shorten the wait time between end of sparge and the start of the boil. A pro system may have limits on how many btus are available or have safety probes that won't let a burner ignite below a certain volume. Homebrew rigs have few if any such limitations.

There are, of course, plenty of other differences in pro vs. homebrew technique. If the pro techniques improve your system and beer, use them, but don't follow for for follow's sake.

Brewfun,

Your reply has to be on the short list of most helpful responses I've ever seen.

You have given me a few things to try out and to think about.

I'll update with results.