I have a recirculating electric BIAB system, and I have always had my efficiency come in a few points lower than it seems like it should. I suspect my LHBS crush could be better optimized for my system, but I want to talk through my observations and get some feedback.
I know I can just add more grain, but because I have a lot of space under the false bottom my mash is in practice very thick regardless of the L/kg calculation. Making it even thicker will force me to reduce pump speed, which slows temperature changes. So, would like to increase my efficiency as much as is reasonably, easily possible before I start adding more grain. That will make brewing big beers easier, too.
I know I can increase time, but that changes fermentability characteristics, and also I want my brew day to be shorter where possible.
For the sake of argument (and also 'cuz I'm sure it's true) assume that glaring mash problems of dough balls and wack pH are not the issue. I also know that my refractometer reads within +/- 1 SG point for the kind of brew discussed in this example, having validated it with hydrometer readings in the past.
What did was monitor the mash conversion efficiency by referring to this chart at Braukaiser. On this brew day, I had an overall mash thickness of 6.98 L/kg. Theoretically, that might get me to a SG of 1.040.
This is what I observed during the 152F mash, which was stirred well every 10 minutes or so, and recirculated at a good clip.
+40 minutes: 1.034.
+50 minutes: 1.0345 -- (approx, obviously, but it was slightly over 1.034)
+60 minutes 1.0365 -- (again, seemed a hair over 1.036)
I called it at +60 minutes as it was close enough to the Beersmith prediction to proceed, but that's predicated on a lame 68% specified Brewhouse Efficiency. Actual values for this run were 64.9% BHE, 72.4% mash efficiency.
I know from past experience that if I let the mash go to 90 minutes, it will creep up a couple more points... so how do I accomplish that in an hour? Or less? People 'round here are doing 20 minute mashes with high efficiency and I can barely get up there in 90 minutes with recirculation and stirring it frequently.
My LHBS says their gap is 1.045, which is in the bounds recommended by the manufacturer of my rig... but I have no way of verifying what the gap actually is.
Is it the crush? Seems like it has to be but I am open to ideas.
I know I can just add more grain, but because I have a lot of space under the false bottom my mash is in practice very thick regardless of the L/kg calculation. Making it even thicker will force me to reduce pump speed, which slows temperature changes. So, would like to increase my efficiency as much as is reasonably, easily possible before I start adding more grain. That will make brewing big beers easier, too.
I know I can increase time, but that changes fermentability characteristics, and also I want my brew day to be shorter where possible.
For the sake of argument (and also 'cuz I'm sure it's true) assume that glaring mash problems of dough balls and wack pH are not the issue. I also know that my refractometer reads within +/- 1 SG point for the kind of brew discussed in this example, having validated it with hydrometer readings in the past.
What did was monitor the mash conversion efficiency by referring to this chart at Braukaiser. On this brew day, I had an overall mash thickness of 6.98 L/kg. Theoretically, that might get me to a SG of 1.040.
This is what I observed during the 152F mash, which was stirred well every 10 minutes or so, and recirculated at a good clip.
+40 minutes: 1.034.
+50 minutes: 1.0345 -- (approx, obviously, but it was slightly over 1.034)
+60 minutes 1.0365 -- (again, seemed a hair over 1.036)
I called it at +60 minutes as it was close enough to the Beersmith prediction to proceed, but that's predicated on a lame 68% specified Brewhouse Efficiency. Actual values for this run were 64.9% BHE, 72.4% mash efficiency.
I know from past experience that if I let the mash go to 90 minutes, it will creep up a couple more points... so how do I accomplish that in an hour? Or less? People 'round here are doing 20 minute mashes with high efficiency and I can barely get up there in 90 minutes with recirculation and stirring it frequently.
My LHBS says their gap is 1.045, which is in the bounds recommended by the manufacturer of my rig... but I have no way of verifying what the gap actually is.
Is it the crush? Seems like it has to be but I am open to ideas.