1BBL Blues - Stuck mash recirculation in a HERMS setup

Since upgrading to a Stout 1BBL setup, I have attempted to maintain the mash temperature by continually recirculating the mash through the HERMS coil. This has worked for my smaller 10-15 gal batches as I can slowly open the recirc valve to full open while setting the grain bed.

The problem I have run into on the last two batches 25 gal and 1bbl, the mash gets stuck and the recirc valve needs to stay fairly closed. Naturally this defeats the purpose of the HERMS coil. For the 1bbl batch, we ultimately ended up stirring the mash throughout the temp rest while having a burner under the MLT. Something is clearly amiss here. Surly I shouldn't have to stir the mash throughout just to maintain the recirculation.

Thanks for any advice.

 

If the re-circulation is happening too quickly it could be causing the grain bed to collapse and get stuck. This is similar to why many larger infusion mash tuns have rakes that are moving at a slow crawl during runoff. Have you experienced and temperature loss during the mash if the re-circulation is slowed? I am not familiar with a HERMS system so I am not sure if a slow recirc is common or not.

 

...and don't call me Surly.

Couldn't resist.

 

Might be a grain bed thinkness issue? Maybe use rice hulls when doing larger batches if you have enough room in your tun.

If say you had a wider tun, you may not have this issue.

 

You may have to open the gap on your grain mill to get enough flow through the system. I brew 1 barrel batches with a HERMS and use a grain mill gap of 0.048-0.050". As stated above, grain bed depth may also be an issue. If it is too deep in your new system, you may not be able to recirculate effectively.

 

I was thinking the same thing. I'll make sure the gap is adjusted ahead of time. Thanks.

 

Seriously? Have you not seen "Airplane?" And the opportunity to change Surely (Shirley) to Surly due to the OP's typo? No "Likes" for this? Okay, now I've become pathetic. Sorry. Never mind. ipe:

 

I picked a bad week to stop sniffing glue.