Morrey and I have been talking about efficiency, squeezing the bag when BIAB, how some people sparge the spent grain....
I offered the possibility that squeezing the bag/grain was functionally analogous to sparging that grain, i.e., rinsing/squeezing essentially accomplished the same thing.
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Yesterday I had a chance to test this in part. I brewed an English bitter of sorts (8# Maris Otter, 3# 2-row, 1# Crystal 60L) using BIAB. Efficiency was on a par with what I was able to do using a traditional mash tun.
I started with 7.25 gallons of water, and after squeezing the bag after mashing I ended up with just about 6.6 gallons of wort. Hard to be certain of the exact amount due of expansion of the hotter water, but about that. I was happy with what I had as a yield.
My pre-boil gravity was 1.053, just a smidge short of the 1.054 I had using this recipe the last time using a mash tun.
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Here's the experimentish approach: After squeezing out what I could, I put the bag and grain in a 5-gallon bucket. Added 2 gallons of RO water to "sparge" with and mixed it up well with a mash paddle. I then hoisted the bag to let it drain into the bucket, and then squeezed until I could recover those 2 gallons.
Wow. I measured the gravity of that wort, and it was 1.020! My brewhouse efficiency is about 77 percent, not quite as good as usual.
But I was shocked by how much sugar survived my squeezing. I usually record first-runnings and second runnings when using a traditional mash tun; that ranges from 1.026 to 1.035, depending on when I start sparging.
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For those will wonder, my mill gap is about 1.020, same as the last three BIAB's I've done. One might wonder if it has grown larger by the adjustment moving a bit, but it was just as hard and long to crush that grain as it was before, so I don't think it has really done that.
Mash temp was 151 degrees, and it held for most of the 60-minute mash. Typically I might mash at 153 or 154, but I want this recipe to produce a bit drier finish. Mash pH was 5.28 measured at 15 minutes into the mash. I stirred the mash well at the 15-minute mark and again at 30 minutes.
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This is only one attempt to look at this issue, but after a first try, the idea that squeezing is analogous to sparging doesn't seem to be the case. Clearly there was a lot of sugar left in the grain after squeezing. The amount of retained water in the spent grain was pretty low, so one would have thought there was enough squeezed out of the grain.
Now, I could have gotten more out of the original grain but I reached a pre-boil volume that was fine, so I just stopped there. Morrey has a sort of basket arrangement he uses and he can press the grain drier than I can, so perhaps with more pressure more of that sugar might come out of the grain.
Thoughts on this?
I offered the possibility that squeezing the bag/grain was functionally analogous to sparging that grain, i.e., rinsing/squeezing essentially accomplished the same thing.
************
Yesterday I had a chance to test this in part. I brewed an English bitter of sorts (8# Maris Otter, 3# 2-row, 1# Crystal 60L) using BIAB. Efficiency was on a par with what I was able to do using a traditional mash tun.
I started with 7.25 gallons of water, and after squeezing the bag after mashing I ended up with just about 6.6 gallons of wort. Hard to be certain of the exact amount due of expansion of the hotter water, but about that. I was happy with what I had as a yield.
My pre-boil gravity was 1.053, just a smidge short of the 1.054 I had using this recipe the last time using a mash tun.
***************
Here's the experimentish approach: After squeezing out what I could, I put the bag and grain in a 5-gallon bucket. Added 2 gallons of RO water to "sparge" with and mixed it up well with a mash paddle. I then hoisted the bag to let it drain into the bucket, and then squeezed until I could recover those 2 gallons.
Wow. I measured the gravity of that wort, and it was 1.020! My brewhouse efficiency is about 77 percent, not quite as good as usual.
But I was shocked by how much sugar survived my squeezing. I usually record first-runnings and second runnings when using a traditional mash tun; that ranges from 1.026 to 1.035, depending on when I start sparging.
***********
For those will wonder, my mill gap is about 1.020, same as the last three BIAB's I've done. One might wonder if it has grown larger by the adjustment moving a bit, but it was just as hard and long to crush that grain as it was before, so I don't think it has really done that.
Mash temp was 151 degrees, and it held for most of the 60-minute mash. Typically I might mash at 153 or 154, but I want this recipe to produce a bit drier finish. Mash pH was 5.28 measured at 15 minutes into the mash. I stirred the mash well at the 15-minute mark and again at 30 minutes.
***********
This is only one attempt to look at this issue, but after a first try, the idea that squeezing is analogous to sparging doesn't seem to be the case. Clearly there was a lot of sugar left in the grain after squeezing. The amount of retained water in the spent grain was pretty low, so one would have thought there was enough squeezed out of the grain.
Now, I could have gotten more out of the original grain but I reached a pre-boil volume that was fine, so I just stopped there. Morrey has a sort of basket arrangement he uses and he can press the grain drier than I can, so perhaps with more pressure more of that sugar might come out of the grain.
Thoughts on this?