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A little update here, mainly for the people reading this in the future.
Long story short, we accomplished small improvements in mash efficiency and run off clarity.
These are some of the things we've been playing with, in case somebody else can find it useful:
– We took apart the rakes and didn't regret it at all. No loss of efficiency and waaaay easier to empty and clean the MLT.
– Following UpsidedownA advice (thank you!) we did a iodine test on the grains after lautering and we found unconverted starch there. So we set the grain mill thinner and we got better mash efficiency in the next batches; from an average of 75% to 80%. Although we have only brewed less than 1.054 pre-boil gravity beers since then.
– We run quite thick mashes now, as thick as 2,2 L/Kg on top of the false bottom. We believe this way we are more likely to get a "floaty" consistency of the mash, with a lot of entrained air in between the grains and less water weight on top of them. This also lets us sparge more for the same pre-boil volume.
– After some minutes of sparge we get better run off clarity, sometimes really good. So that's another reason for the thick mash. We've never gotten less than 1.012 last runnings, with an average of 1.021. And pH never goes out of control because we acidify the HLT water.
– We suspect that the pump we were using for vorlauf is too aggresive. Even with a VFD it cannot run gently enough (we think), so now we vorlauf by gravity into the kettle and pump it back on top of the MLT. We do this twice in the middle of the sacch rest combined with some stirring and twice before lauter. Then we lauter by gravity and do not switch to pump until we have at least 300L in the BK.
– When we want more wort clarity (not always) we use Protafloc Granules and it helps a lot.
The mashes we are still having low efficiency with are mainly higher gravity (1.058 and above) and beers with high amounts of non-barley grains (+40% wheat malt) and/or flaked stuff (wheat, oats...). Thanks a lot to everybody who replied to this thread so far. We will keep trying to improve on this; the battle is not over!
Long story short, we accomplished small improvements in mash efficiency and run off clarity.
These are some of the things we've been playing with, in case somebody else can find it useful:
– We took apart the rakes and didn't regret it at all. No loss of efficiency and waaaay easier to empty and clean the MLT.
– Following UpsidedownA advice (thank you!) we did a iodine test on the grains after lautering and we found unconverted starch there. So we set the grain mill thinner and we got better mash efficiency in the next batches; from an average of 75% to 80%. Although we have only brewed less than 1.054 pre-boil gravity beers since then.
– We run quite thick mashes now, as thick as 2,2 L/Kg on top of the false bottom. We believe this way we are more likely to get a "floaty" consistency of the mash, with a lot of entrained air in between the grains and less water weight on top of them. This also lets us sparge more for the same pre-boil volume.
– After some minutes of sparge we get better run off clarity, sometimes really good. So that's another reason for the thick mash. We've never gotten less than 1.012 last runnings, with an average of 1.021. And pH never goes out of control because we acidify the HLT water.
– We suspect that the pump we were using for vorlauf is too aggresive. Even with a VFD it cannot run gently enough (we think), so now we vorlauf by gravity into the kettle and pump it back on top of the MLT. We do this twice in the middle of the sacch rest combined with some stirring and twice before lauter. Then we lauter by gravity and do not switch to pump until we have at least 300L in the BK.
– When we want more wort clarity (not always) we use Protafloc Granules and it helps a lot.
The mashes we are still having low efficiency with are mainly higher gravity (1.058 and above) and beers with high amounts of non-barley grains (+40% wheat malt) and/or flaked stuff (wheat, oats...). Thanks a lot to everybody who replied to this thread so far. We will keep trying to improve on this; the battle is not over!
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