I just calculated my mash efficiency for my first AG batch as 82%. I'm kind of astonished, so just wanted to make sure I'm calculating correctly.
Bear with me -- it's not as straightforward it should have been, because of a little mistake I made:
I was aiming for a pre-boil volume of 7.4 gallons. Got 2.5 gallons of first runnings, leaving 4.9 to go. First sparge got me 2.5 more gallons (5.0 gallons so far, 2.4 to go), second sparge got me 1.5 gallons ... but the lid was on the MLT and I had gathered both sparges into the same bucket and wasn't really thinking "hey, where's my other .9 gallons??"
I figured the grain had absorbed more water than I had accounted for, poured all the wort into the keggle, and added .9 gallons of water to bring my pre-boil volume up to 7.4 gallons.
Then I lifted the MLT and found that I had a stuck sparge and the other .9 gallons was still in there.
So I figured I'd add some DME since my volume was already good. I took a gravity reading and got (adjusted for temp) 1.046. Expected pre-boil gravity was 1.042, so I thought, wow, I did pretty well to beat my gravity by 4 points even after diluting the wort with almost a gallon of water! And I didn't add any DME.
I also collected the remaining .9 gallons from the MLT (I guess I'll add some DME and boil it up for starter use). I took a gravity reading and it was 1.029.
I didn't directly measure the gravity of the wort before I added the .9 gallons of water, but I calculated it as follows, since I measured the pre-boil gravity (with the water) and the .9 gallons left in the MLT that I didn't use.
Just want to make sure I'm doing this right... sounds logical to me:
(6.5 gallons * X ) + (0.9 gallons * 1.000) = 7.4 * 1.046
6.5X + 0.900 = 7.740
6.5X = 6.840
X = 1.052
... so the gravity of my wort before I added the water was 1.052.
If I had used the .9 gallons of 1.029 wort instead of the water, my pre-boil gravity would have been (Y) ...
(6.5 gallons * 1.052) + (0.9 gallons * 1.029) = 7.4 * Y
6.838 + 0.926 = 7.4Y
7.764 = 7.4Y
Y = 1.049
At 70% efficiency, BeerSmith calculated my pre-boil target gravity at 1.042.
Keeping in mind I'm trying to calculate my mash efficiency (i.e., efficiency if I had used everything that came out of the MLT and not added water to the wort), I get the following:
49/42 = 1.167
1.167 * 70% = ~ 82%
I hope someone followed all that...
Sound right?
Just wasn't expecting 82% for the first one.
Bear with me -- it's not as straightforward it should have been, because of a little mistake I made:
I was aiming for a pre-boil volume of 7.4 gallons. Got 2.5 gallons of first runnings, leaving 4.9 to go. First sparge got me 2.5 more gallons (5.0 gallons so far, 2.4 to go), second sparge got me 1.5 gallons ... but the lid was on the MLT and I had gathered both sparges into the same bucket and wasn't really thinking "hey, where's my other .9 gallons??"
I figured the grain had absorbed more water than I had accounted for, poured all the wort into the keggle, and added .9 gallons of water to bring my pre-boil volume up to 7.4 gallons.
Then I lifted the MLT and found that I had a stuck sparge and the other .9 gallons was still in there.
So I figured I'd add some DME since my volume was already good. I took a gravity reading and got (adjusted for temp) 1.046. Expected pre-boil gravity was 1.042, so I thought, wow, I did pretty well to beat my gravity by 4 points even after diluting the wort with almost a gallon of water! And I didn't add any DME.
I also collected the remaining .9 gallons from the MLT (I guess I'll add some DME and boil it up for starter use). I took a gravity reading and it was 1.029.
I didn't directly measure the gravity of the wort before I added the .9 gallons of water, but I calculated it as follows, since I measured the pre-boil gravity (with the water) and the .9 gallons left in the MLT that I didn't use.
Just want to make sure I'm doing this right... sounds logical to me:
(6.5 gallons * X ) + (0.9 gallons * 1.000) = 7.4 * 1.046
6.5X + 0.900 = 7.740
6.5X = 6.840
X = 1.052
... so the gravity of my wort before I added the water was 1.052.
If I had used the .9 gallons of 1.029 wort instead of the water, my pre-boil gravity would have been (Y) ...
(6.5 gallons * 1.052) + (0.9 gallons * 1.029) = 7.4 * Y
6.838 + 0.926 = 7.4Y
7.764 = 7.4Y
Y = 1.049
At 70% efficiency, BeerSmith calculated my pre-boil target gravity at 1.042.
Keeping in mind I'm trying to calculate my mash efficiency (i.e., efficiency if I had used everything that came out of the MLT and not added water to the wort), I get the following:
49/42 = 1.167
1.167 * 70% = ~ 82%
I hope someone followed all that...
Sound right? Just wasn't expecting 82% for the first one.
:cross:
