Ok, crush... troubleshoot me.

[mchrispen]

So, it pains me to admit this, but I am having serious mash efficiency issues.

I first noticed (now that I look back on my notes) the issue with a LODO Kolsch that my efficiency dropped a few points from my normal. I think I mentioned this, and tightened down my MM3 and started malt conditioning. Since, my mash efficiency has gone further and further down. Some of this is lauter technique, but there is a consistent theme of lower than normal, sometimes extreme lack of conversion, all with SMB dosages at the recommended rate. I have done everything possible to isolate the issue - and conclude that either; my crush is still not adequately fine, or SMB is interfering with beta-enzyme activity, or a little of both. Everything else has been good - mash pH, water chemistry, high quality continental malt (Weyermann Pils, Barke, BM Heidelberg).

On the Brew-Magic, the crush needs to be coarse enough to allow for circulation during the mash. It's a hybrid RIMS/direct fire system. My MMS is now set at 0.030" and I need to use rice hulls to ensure circulation. For the most part, grain in is at 144F, stepped to 158/160F, mash out, sparge under mash cap slowly. I tried an infusion mash at 152F and still had a 50% mash efficiency. I am leaning toward the crush, because the SMB didn't greatly affect conversion on a few previous batches.

Later today, I am dropping my mill gap to the tightest setting and doing a few mini-mash batches.

Does anyone here use just a false bottom for their HERMS/RIMS system? I know a bag will allow for a much tighter mill. Can you take some close up pics of the grind and post them? I will do the same here in a bit.

[Bryan R]

Are you stirring on dough in? Are you sparging?

[Kit_B]

Have you been tracking your pH?

(I only mention it, because of the recent sacks of Rahr that Bryan got with a very high pH.)

[mchrispen]

Mash pH is nearly perfect. 5.5-5.35 depending on the base malt.

Mash is under let. One gentle stir after full transfer if needed. No dough balls at all. Circulation at about 1 g per minute. Throttled behind the pump. Clear wort pretty quickly.

I just pulled a couple of pounds through a 0.025" gap, conditioned, MM3. This crush would stick my system like concrete.


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[Bryan R]

Is this no sparge?

[mchrispen]

Fly. Although I had the same issue on a no sparge on the GrainFather.


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[mchrispen]

Also - I checked the temps - all accurate.


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[Kit_B]

So, these results are from more than one lot of base malt?
That is very strange.

[mchrispen]

Yeah - it has me head scratching.

I did a mini-mash comparison. 800 ml mash, 655 ml RO water, no salts, with 170 grams of BM Heidelberg crushed at 0.025 on the MM3. No acid added, mashed in a sous vide bath for over 1 hour at 150F. 1.025 with SMB (65 mg SMB added - pH 5.6), 1.035 without SMB (pH 5.7). Drained, not sparged. Both yielded 500 ml liquor. FYI - both yielded a DO measure well under 1.0 - but I used SMB water to condition (25 mg/l).

I am seriously baffled. WTF am I doing wrong.

[Bryan R]

I don't have much to add except no issues in the over 100 batches of lodo brewing here.