Attenuation challenge: Too hot HLT or too much recirc? Advice needed

[Steve Amey]

I have been noticing that ever since I went to my HERMS mash and conical fermenter, I have ended up at FG at the top of styles.  This is happening on recipes that I had done for years under my older system.  Only difference is using HERMS and the conical.  Question is why and whether I’m doing something I shouldn’t.  Advice is very welcome.

What do I typically do in my HERMS system :

Set HLT to a little above my strike temp, transfer mash volume to MT, recirculate until it is at my strike temp, mash in.  And then one of two things happens —

• I either moved the HLT to 180 and set the MT PID to the sach temp; Thus, having the HERMS not really doing HERMs, but having the recirc only when temp drops.
• or I set the HLT to about the Sach temp and set the MT PID to higher; thus forcing the system to recirculate constantly.

What should I be doing?  I am wondering if I set the HLT too high, do I denature the enzymes or if I recirculate at higher than the Sach temp, do I end up with more long chain sugars, thus being less fermentable.

I take very careful notes….but apparently not of this stuff. 🙁  I seem to be finding circumstantial evidence that I should do more the latter than the former, but could use some advice.  Thanks, Steve

[Steve Amey]

A second possibility is that my conical is doing something that makes the yeast less effective (e.g., trapping them down at the bottom in less surface area…makes sense for a lager, but for ales?).   Anyone else use conicals and notice they have to do anything different?

I could try increasing my pitch (I use a 1.5 L starter that I typically get going the day or two prior, mostly just to wake  up the Wyeast or WL pitch).  I put yeast nutrient into the starter, but not into my boil kettle.

Any other places I should look to solve this?

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