Attenuation and mash problems with an eHERMS system

[luckybeagle]

I used to do single-infusion batch sparges with a cheap 10 gallon igloo cooler setup. My efficiency was about 72% in most batches. I consistently had high attenuation and made beautifully dry beers (I primarily brew Belgian style ales).

Once I moved to my new house (just down the street, same municipal water supply), I put together a 3 vessel, 30A eHERMS system (similar to theelectricbrewery.com's) and ditched the cooler. My efficiency increased to about 80% or so (not as high as I was expecting, but better), but my attenuation has been lower across most of my beers. Like 5-7 points lower than what I was achieving brewing the same recipes on my batch sparge setup. I also now do step mashes for most of my Belgians, so if anything I thought it'd have gone up?

Could my low attenuation and slightly low efficiency be due to my fly sparging process? I've heard fly sparging for an hour can result in less efficiency if your sparge water pH isn't where it needs to be. Our tap water is a pH of 7.4, but I'm pretty sure my preboil sweet wort is around 5.4, IIRC? I only treat my tap water with Campden tablets currently.

I've done low-and-slow, single temperature mashes (always recirculating through the herms coil, though) and step mashes, and still seem to have these attenuation issues.

Any thoughts or ideas on how to improve these numbers? Efficiency is less of a concern than attenuation, though maybe my problems with both share a common cause?

 

[Brettomomyces]

Are you adjusting mash pH? It might be a little high.

I also have a HERMS setup and after I dough in I stop the recirc and do an initial rest, then when I'm going to the next mash step I turn the circulation pump back on. This ensure beta amylase is doing its job and not affected by the higher temp in the HLT. 144 -> 162 - 172 is typically what I do, and leave the pump running once I'm done with my 144 rest.

 

[luckybeagle]

Are you adjusting mash pH? It might be a little high.

I also have a HERMS setup and after I dough in I stop the recirc and do an initial rest, then when I'm going to the next mash step I turn the circulation pump back on. This ensure beta amylase is doing its job and not affected by the higher temp in the HLT. 144 -> 162 - 172 is typically what I do, and leave the pump running once I'm done with my 144 rest.

I recirculate throughout the mash but keep the temperature in my HLT at whatever rest temperature I'm shooting for via the PID controller until I'm ready to step up, so I don't think this could be my issue, but I'm very curious about the mash pH. How do you adjust your mash pH? Do you add acid to the hot liquor before doughing in, during the sparge, or something to the grist?

My process, in case I'm doing something wrong (I've only done 5 or 6 batches on this system):

I typically start with 15 gallons in my HLT, add campden and set the PID to my first rest temperature (+2F to account for temperature loss in pumping). I circulate with Pump 1 from the bottom of the HLT to the top for even temperature distribution. Concurrently I fill up my MLT to my strike volume, add campden, and flip on Pump 2, to recirculate through the herms coil in the HLT and back into the MLT. I let this run for a half hour or so and then dough in with Pump 2 off. Then I slowly open pump 2 until it's full-bore (or half bore if using wheat malt). If I do a protein rest, I'll dough in at 122-124F and hold for 20 minutes, then raise and hold the temp in the HLT to 148 or so for 60 to 90 minutes. Then I'll bump to 170F for 20 minutes. After that I fly sparge over 45 minutes to an hour (depending on 5 or 10g batch size). I'm pretty sure my sweet wort pH is about 5.2 - 5.4 after it's all in the boil kettle. Should I instead measure the "first runnings?"

 

[day_trippr]

This is likely a simple problem, but to actually understand what's going on one would need to know if the OP is hitting the planned volume to fermentors at the planned specific gravity. I don't see that state mentioned.

If those two conditions are met, then it comes down to mash temperature profile...or a pitch problem (with the latter less likely, imo).
Otoh, if the OG was missed at the expected volume, more factors come into play...

Cheers!

 

[RM-MN]

I used to do single-infusion batch sparges with a cheap 10 gallon igloo cooler setup. My efficiency was about 72% in most batches. I consistently had high attenuation and made beautifully dry beers (I primarily brew Belgian style ales).

With this setup your attenuation is determined by the mash temperature as you can make it the right temp for good attenuation and the enzymes work as you expect.

I've done low-and-slow, single temperature mashes (always recirculating through the herms coil, though) and step mashes, and still seem to have these attenuation issues.

When you recirculate during the mash with your eherms, your wort enters the eherms just slightly below the desired mash temp, then is heated in the coil to bring the rest of the mash up a little in temp. I think (Just an opinion) that while that wort is passing through the eherms the temperature rises enough to destroy some of the beta amylase. If you recirculate long enough you will have eliminated the enzyme you need working.