Efficiency problems

[Jordanlabstick]

So I bought a new system, the 10 gallon ss brewtech bme set up and modified it a little to include a herms. For the last 11 brews I've made over 92% efficiency, Twice being 98%. I do a 3 step mash for all of my Belgian styles or wheat beers and 2 step for other ales. All including a mash out to at least 165°f (sparge at 172 for about 30-45 minutes.)
these beers will not finish past 1.020 1.018 and are hazy and meh... it hasn't been a bad quality in the wheat beers but doesn't work well for IPAs. The only beer I've ever had finish low was an IPA that I did a single infusion on. And the efficiency of that was at 72%

So for some reason when I use my herms my efficiency goes crazy high and my fermentation sticks. Even French saison yeast won't drop these suckers.

I've changed the scale I use, checked all of my calculations, had professors check calculations, changed my grind settings,adjusted ph different and I've literally put my entire cold side through an autoclave to ensure it wasn't an infection of some sort that was causing them To not finish.
I don't know if anyone has had this problem but is there a connection between recirculating too long and this problem?

 

[RM-MN]

Your HERMS system is getting the mash too hot and denaturing the beta amylase. Slow the flow so you aren't recirculating as much.

 

[dmtaylor]

Quit doing complex 3-step mashes with mashout, and just do single infusion without mashout.

 

[GPP33]

What is the gravity of your final runnings? Could you be simply over sparging?

 

[IslandLizard]

It surely seems to point to your recirculating mash system.

Your HERMS system is getting the mash too hot and denaturing the beta amylase. Slow the flow so you aren't recirculating as much.

This could also point to the wort going through the HLT getting too hot, thus starting to denature beta amylase right there. You're making dextrin soup.
Slowing the flow will be even more detrimental in that case. You should monitor (and control) the wort temp from the HERMS as closely to the exit port as possible and adjust recirculation speed and HLT temps accordingly.

Don't recirculate crazy fast, the mash needs time to work.

What is your water like? Have you measured the actual mash pH (sample chilled to room temps)?

Regarding your efficiencies, they all depend on how you define them. 98% mash efficiency is unheard of. Don't stare blind on those numbers either, keep the goal in mind: making wonderful, tasty beer!

Infections tend to over-attenuate beer, not stall them. You would know by appearance and taste when that happens.
What kind of yeast are you using? If liquid, do you make starters?

 

[Jordanlabstick]

It usually takes about 15 minutes to raise 10°. I didn't think that was too fast for 10 gallons. What temperatures should I aim for coming out of the herms then. If im going from 113 to 136 or 136 to 146 ect.
This still doesn't make since though. Because decoction mashing doesn't create this problem and you literally boil part of your mash.

 

[IslandLizard]

No, 15 minutes for a 10°F (?) rise is not too quick. Are you sure your temps are calibrated? Maybe you're mashing 5-10°F too high overall?

You want to make sure the temps coming out the HERMS are not much above the next step's temp (rest) and not to exceed 154-156F unless that is the last step's temp (rest), before mashout.

Decoction is a whole different process, although you ultimately boil part of the mash (the decoction portions), the decoctions themselves are each step mashed while the main mash is kept at its own rest temp in the mash tun, awaiting the next rise (step) from the decoction being added back. Those mashes are really expertly done to create a well designed sugar and flavor profile.

 

[RM-MN]

It usually takes about 15 minutes to raise 10°. I didn't think that was too fast for 10 gallons. What temperatures should I aim for coming out of the herms then. If im going from 113 to 136 or 136 to 146 ect.
This still doesn't make since though. Because decoction mashing doesn't create this problem and you literally boil part of your mash.

Only part of the mash is boiled for decoction. You're running all your mash through the HERMS. If it gets too hot there it denatures the beta amylase in all of it. I'd check the temperature of the output of the HERMS. Beta amyalse denatures at mash temps fairly quickly which is how you adjust the fermentability by mashing at different temperatures.

 

[Dog House Brew]

What is your HLT temp when you’re making your rise? I quit using my HERMS because I had the same problem several years ago. I was running to high in my HLT. I was under the impression then that ramps had to be fast. I had IPA beers finishing at 20. I’m going to do a few batches coming up to actually see if HERMS and stepping improves over single infusion.

 

[IslandLizard]

One of my brew friends uses a mini eHERMS on his 15 gallon 3 kettle system. A small, 1 gallon pot with water powered by an cheap, ordinary 110V water heater element containing a 6' SS wort coil. A PID controls the heating element based on the output temp of the wort coil. When ramping up, the eHERMS pot gets to a boil occasionally, but the output wort temp remains at the set mash step temp. Circulation speed is low to moderate, a gallon a minute or so. Because the eHERMS vessel is small and the coil is short, the system has a relatively fast response, which really gives it that hands on feel. He's never had elevated FG problems.