pdietert said:
The point was that if you have more liquid left in the MT at the end of the sparge the gravity of it will be considerably less than the the gravity of the wort. Adding it to the wort would reduce the gravity of the wort, so it appears that nosnhojm20's efficiency problem is not related to leaving liquid in the MT.
This is not correct. Think about it, your first runnings are the highest gravity right? So if you pull just a few ounces of say 1.090 wort and stop is that your best efficiency? Of course not! As the sparge continues yes, the gravity drops but the VOLUME collected goes up, so the total sugars collected goes up. For example:
-10 # of 2-row, target 5 gallon batch
- I think 2-row has an extract potential of 1.037
- calculate by deleting the 1 digit
- 37 x 10 = 370, / 5 (gallons) = 74, or 1.074 at 100% efficiency.
- Say you collected 5 gallons of 1.052, and I collected 6 gallons of 1.046, who got better efficiency?
- 5 gallons of 1.052 is 260 "gravity points"(5x52)
- extract potential is 370, so that's 70%
- 6 gallons of 1.046 is 276 points (6x46)
- extract potential is STILL 370, so that's about 75% even though the gravity is lower.
So you can see if you sparge more, you can drive up your efficiency. The trouble is, you may have more to boil off than 60 or even 90 minutes will accomplish. Once I understood this concept, I lost my ego about efficiency numbers. Grain is a fairly inexpensive part of brewing, so I figure the number of GRAVITY POINTS I need for a batch and low ball my expected efficiency. This way I ALWAYS get enough fermentables for my batch, and if I get more I can either stop early and save time, or make a bigger batch! Either way it's a win win for just a few bucks more worth of grain...