minderman has a good post to read
hydros are usually set at 60 or 68 degrees, find what yours is set at then check it, it should read 1.000 at one of those degrees
we need to find if that hydro is set right to see if we are even comparing apples to apples, understand
now about efficiency, are you saying that you suspect that you are getting bad efficiency because of grain grind?, OK
After we are sure we are able to trust your hydro, We want to see about
I suggest we get 5 pounds of 2 row, pre ground, bring it home and do a mash, 1.5 qts to a pound at 150 degrees
after an hour sparge it to your normal style of spargeing, collect 6 gallons
take a reading of it at whatever your hydro is set for. then boil off a gallon and take another reading.
both readings make sure the temp of the sample is at the setting of your hydro
this will be your base line sample. all test need a base line so we now have just established what a commercial ground malt will do with your system
now we do the same with 5 pounds of 2 row that you ground
now we can compare apples to apples
And work on it from there
Do you understand ?