Hot answers tagged efficiency
Putting 10.5kg of grain in 11.5 litres of water will kill your efficiency, unfortunately: From Braukaiser: Traditional British style infusion mashes are with about 2-2.5 l/kg (1 - 1.15 qt/lb) very thick and German style mashes are generally much thinner (3.5-5 l/kg / 1.75-2.5 qt/lb). Historically this is rooted in the fact that the latter needed to ...
Your efficiency goes down as the gravity of your beer goes up. That's because of the sugar you leave behind when using a "normal" amount of water. In order to increase your effieincy, you need to sparge more. That also means you need to boil longer to drive off the extra water.
Are you sure your calculating your 100% correctly? Or more importantly have you measured your collected volume precisely this can through off your calculation significantly too. I batch sparge as well. Once I have all my wort collected I start my burner, give it a quick stir and take an immediate sample for preboil gravity. It doesn't take much of a stir ...
A refractometer helps too, since you don't need to adjust for temperature and can use a very small sample. I normally rack the wort before I take a reading (and measure volume) which helps to evenly distribute the sparge and first runnings.
It's best to measure as the wort comes to the boil for the reasons you mention - all the wort is at the same temperature and the convection currents have mixed the wort fully, so you get a much more accurate reading.
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