Fine Crush and efficiency

[TheDaysy]

I brew using no sparge BIAB and have seen it recommended in a few places to use a fine grain crush to increase efficiency.
However I seem to be finding the opposite, I ordered my last batch of grain from malt Miller with a fine crush and have since had my efficiency drop from 69% to 64%, does anyone have any advice for me on how to work with grain at a fine Crush as I'm sure it is something that I'm doing that is causing the problems

 

[BlackIsland]

My first thought is that you've got a measurement error. On small scale, it takes very little in the measuring department to make the efficiency appear to swing wildly.

Another possible variable is the water retention in the grain. Squeezing vs not squeezing can change the numbers as well.

I use a corn grinder (aka Corona mill) to mill my grain as fine as it will go, I mash in a fixed amount of water (depending on batch size), drain the bag and dunk it in the remaining water and add that back to the kettle, and always get within a few percent of 85% MASH efficiency, with very little variation. I also squeeze the bag like it owes me money.

 

[TheDaysy]

My first thought is that you've got a measurement error. On small scale, it takes very little in the measuring department to make the efficiency appear to swing wildly.

Another possible variable is the water retention in the grain. Squeezing vs not squeezing can change the numbers as well.

I use a corn grinder (aka Corona mill) to mill my grain as fine as it will go, I mash in a fixed amount of water (depending on batch size), drain the bag and dunk it in the remaining water and add that back to the kettle, and always get within a few percent of 85% MASH efficiency, with very little variation. I also squeeze the bag like it owes me money.

I think you might have got it with the squeeze, I normally squeeze my grain dry but did notice it was wetter than normal when I tipped it out today, I hadn't realised how much of a difference that could make

 

[BlackIsland]

I think you might have got it with the squeeze, I normally squeeze my grain dry but did notice it was wetter than normal when I tipped it out today, I hadn't realised how much of a difference that could make

Yeah, on 5 gallon batches, it doesn't take much to make the numbers swing. I don't really care about efficiency, but I do want predictability.

 

[TheDaysy]

Yeah, on 5 gallon batches, it doesn't take much to make the numbers swing. I don't really care about efficiency, but I do want predictability.

I brew 1 gal batches so I do struggle a bit with predictability, I have gotten quite consistent on my last 5 brews but couldn't resist the temptation to try change something, should have just stuck to what was working

 

[Brewed_Force]

I just entered my figures for my current brew into 2 different brewhouse efficiency calculators and both came out ~100%
I use BIAB method with a fine crush and dunk sparge then squeeze the bejeezus out of the bag. I measure with a refractometer (OG was 12 brix which equates to 1.048 - I was expecting 1.043 from the recipe - FG is 5 brix which calculates to 6% ABV , again I was expecting about 4%)
Should I phone the Guiness Book of Records is it more likely my refractometer needs adjusting ?

 

[TheDaysy]

I just entered my figures for my current brew into 2 different brewhouse efficiency calculators and both came out ~100%
I use BIAB method with a fine crush and dunk sparge then squeeze the bejeezus out of the bag. I measure with a refractometer (OG was 12 brix which equates to 1.048 - I was expecting 1.043 from the recipe - FG is 5 brix which calculates to 6% ABV , again I was expecting about 4%)
Should I phone the Guiness Book of Records is it more likely my refractometer needs adjusting ?

Refractometers don't read properly once there is alcohol in the sample so that probably explains your ABV.
You shouldn't ever see 100% brewhouse efficiency either, it's most likely that is down to measuring the volume of wort that went into the fermenter incorrectly.

 

[Drunkula]

I measure with a refractometer (OG was 12 brix which equates to 1.048 - I was expecting 1.043 from the recipe - FG is 5 brix which calculates to 6% ABV , again I was expecting about 4%)

https://www.brewersfriend.com/abv-calculator/
Change the settings to plato. 12 -> 5 plato is 3.8%. The calculator does all the tinkering for you that you need when using refractometers for final gravity.