So, losing my mind a little bit...
I'm having a hard time getting consistent efficiency and I think it is in my conversion. I've been making a lot of adjustments to my process in an attempt to get above the 54% efficiency mark where I have been sitting. I've calibrated about 30 thermometers, 3 hydrometers, re-evaluated my grain crush, checked mash pH..... I've really been trying to nail this down, and I seem to be getting no where.
This past weekend I brewed what was supposed to be a 5.5 gallon batch. I used beercalculus.com to build my recipe, I left the efficiency setting at 75, thinking that all the small changes I had made would add up. According to BC, my OG with a 75% efficiency should have been 1.079. (12lbs 2-row, 2.5 lbs specialties) I mash in an igloo cooler with a 1.5 qt/lb water:grain ratio. This time, that ratio was even a bit higher because I wasted a lot of heat really thoroughly stirring my mash around to wet all of the grains, so I had to add a little more than a galolon of boiling to the mash, so my ratio was closer to 1.94. The pH of my mash was 6.0 according to my pHydrion strips. A little high, but I didn't have any citric acid lying around, so I went with it. I mashed for 60 minutes, stirring about 4 times over the hour. Temperature was still good when I started my lauter.
Now, the real problems. I collected my first runnings, and let them cool while I was lautering. At 90°F, the gravity was 1.050. In my mind, my first runnings should have been over 1.080. Feel free to tell me I'm wrong here. I was trying to collect 6.5 gallons, and then boil for an hour. I fly sparged with 170°F water until the runnings were plainly not sweet, but at this point I had collected 8.5 gallons. Even after overlautering, my total gravity in the 8.5 gallons was only 1.035. In my mind, 35 points in 8.5 gallons only equals 54 points in 5.5 gallons. (Again, feel free to tell me I'm wrong about this math) So, 1.054 is a far cry from 1.079. So I changed everything up and tried to add in some extra points with some DME. Added half a pound to the boil (all I had on hand thankfully), and then boiled for an hour before I started my hop addition. After being pretty fed up with what should have been a perfectly good brew day, I accidentally boiled for too long, and so I ended up with only 4 gallons of chilled wort, but it was at 1.084. Had I hit my target volume, and not added the DME (only 3.3 points in 5.5 gallons me thinks) I would have been at 1.058. Damn close to my first runnings, and WAY under my target.
So, now that you have read my overly long brew day story, what other information can I give you so you can tell me what the hell I'm doing wrong. I got lucky on this one that I will recover a beer close to what I wanted in the first place, but it sure would be nice to have the extra 1.5 gallons of beer when I work this hard for it. Also, I'd love to be able to brew a beer twice and get the same beer out. So far, reproduciblility is a long ways off.
Thanks so much in advance.