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Measured Mash Effeciency


Grandmaster Brewer
Dec 28, 2011
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So confused

Measured Mash Efficiency in the design tab only changes when the Measured Pre-Vol changes, not when adjusting the pre-boil gravity.  Now moving to the sessions tab, the measure post mash gravity does change the measured mash efficiency on both the sessions tab and the design tab.

The measure post mash gravity pop up indicates its out of the mash, with boil top up water.  Well if you don't add any top up water, then the reading is the same so why doesn't the value in the design tab update the measured mash efficiency?

There has to be a better way to follow this


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
If I am following you correctly, you have on your design page the fields for post mash volume (meas pre-boil vol) and post mash gravity and when you change the volume field you are seeing a change in the mash efficiency but when you change the gravity field you are not? 

In trying to replicate this, I figured out that you need to add the field for 'meas post mash gravity' to get the mash efficiency to change.  The program does not know that you did not add anything to adjust the gravity between the post-mash and pre-boil, so it does not use the pre-boil gravity for calculating your mash efficiency.  This is why the mash efficiency does not change on your design page when you adjust the pre-boil efficiency.  This allows for the brewer to add sugars (simple, DME, LME or other) to the boil kettle without giving an erroneous calculation for mash efficiency, even if the recipe did not call for it.