HERMS recirculation efficiency question

I had poor efficiency on my last batch which also happened to be my first use of the HERMS system. It is basicilly like the POLS with the exception of using a SS keg for the HLT. Normally I get 79-84% efficiency. This batch was 66%. I ended up adding .75 lb of light DME to bring up the OG.

Anyway, someone mentioned that maybe the water was flowing too fast and did not have enough contact time with the grain to properly activate the enzymes. Does this theory have any merit?

I mashed for 60 minutes at 150 F while recirculating. Then raised the HLT to 174 while still circulating which took about 25 minutes and then fly sparged. I probably fly sparged too quickly as I have to get used to using pumps..

Ironically the only other batch that had poor efficiency was also a Kolsch and I didn't use any Gypsum on either. Maybe water hardness had some effect. I always use 5.2 and did on this batch as well. I add Gypsum on all my other batches except Kolsch.

Last, it was my first time crushing with my new barley crusher. I did not check the factory settings but there was some powder when done and I just assumed it was ok.

In a word, no.

I am going to say no.

I recirc. pretty fast on the Brew Beast... and my eff. is stuck at 82% each time.

Now, the BC factory setting should get you about 80% eff. THOUGH, without checking it, maybe it was a little off? Not enough to get you 66% though.

You mashed out just like I do...

I take about 30-40 minutes to fly sparge a typical 5 gallon brew.

This may not HELP, but hopefully it shows you that your METHODS are good, something else is awry.

It was just a thought..

I wonder about water chemistry?

The only 2 that were below 79% were the first AG and the last one. Both were Kolsch which is the only 2 times I have used Pilsner malt but I doubt that is the problem. On the first, I did not add anything to the water and I used RO which was a mistake. All the subsequent ones have had 5.2 and gypsum because I wanted to raise the calcium levels. I always use my tap water now. On this last one, thinking Kolsch should have soft water, I did not add the gypsum. I generally use more 5.2 than it calls for treating all gallons and not just for the finished 5.5 gallon batch. In other words I treat the sparge water as well. I just put it in the HLT before I begin heating.

Check the BC and maybe you have to deal with chemistry.

OKAY, I use spring and distilled water and 5.2 buffer. Nothing special, but I get 80+% regardless.

I'll definitely check the BC.

Yep, I think the RO water was a big part of the first one. On the next couple, I used half tap water and half bottled from the local grocery store. I slowly weened off the bottle to all tap but was adding 5.2 and gypsum.

I'm going to try to brew another batch this week. I'll let you know how it goes.