So yesterday I had my first real mash failure on 2 of the 3 batches I brewed. Im talking super low efficiency in the ~30% range. All three batches were done concurrently (3 MTs, 3 kettles, etc.) The only difference that stands out is that the batch that hit my target spot on was primarily great western 2 row in a ten pound bag. The two low efficiency batches came from my first fifty pound sack of the same.
They were milled the same way, and mashed side by side by side. Temperatures were nearly spot on at 152, for 45 to 50 minutes. Its my own fault for only performing an iodine test on the first batch, which happened to be the one that converted well. Had I done a pre-boil gravity reading, I might have caught the problem, but sadly I didnt realize anything was awry until I took the SG reading on all three. When the refractometer read so low, I double checked with the hydrometer. I had a 3 lb bag of DME that helped me get some lost gravity back, but it certainly wasn't enough to hit my targets.
Any ideas why the big bag of malt didnt convert as well?
Batch 1 - Sierra Nevada Clone
11# 2-row, 1# 40L (10 lb bag)
Target: 1.052
Measured: 1.051
Efficiency:65%
Batch 2 - Amber Ale
8# 2-Row, 2# Munich, 1# 60L, 1# 90L (Big Sack)
Target: 1.052
Measured: 1.024
Efficiency: 28%
Batch 3 - Pliny the Elder Clone
14 Lbs 2-Row, .75 CaraPils, .75 40L, .75 Dextrose (Big Sack)
Target: 1.075
Measured: 1.044
Efficiency: 35%
They were milled the same way, and mashed side by side by side. Temperatures were nearly spot on at 152, for 45 to 50 minutes. Its my own fault for only performing an iodine test on the first batch, which happened to be the one that converted well. Had I done a pre-boil gravity reading, I might have caught the problem, but sadly I didnt realize anything was awry until I took the SG reading on all three. When the refractometer read so low, I double checked with the hydrometer. I had a 3 lb bag of DME that helped me get some lost gravity back, but it certainly wasn't enough to hit my targets.
Any ideas why the big bag of malt didnt convert as well?
Batch 1 - Sierra Nevada Clone
11# 2-row, 1# 40L (10 lb bag)
Target: 1.052
Measured: 1.051
Efficiency:65%
Batch 2 - Amber Ale
8# 2-Row, 2# Munich, 1# 60L, 1# 90L (Big Sack)
Target: 1.052
Measured: 1.024
Efficiency: 28%
Batch 3 - Pliny the Elder Clone
14 Lbs 2-Row, .75 CaraPils, .75 40L, .75 Dextrose (Big Sack)
Target: 1.075
Measured: 1.044
Efficiency: 35%