We’ve been experiencing a strange vacuum in our mash runoff, pretty independent of the grist. Looking to the tribe for some problem solving thoughts.
Below are the details, but what we’re mostly seeing is the grain bed drop 10” almost immediately, even with a very slow vorlauf and sparge. When it starts to slow down, we see big air bubbles go back up the hose, through the sight glass and back into the mashtun. Sometimes the run off goes completely dry, but the mash still has an enormous amount of water in it. When this has happened and we finally call it, if we start graining out and shove a shovel into the grain bed, you can hear the vacuum break up.
Mash tun: homemade 7bbl, we push 10bbl batches out of it. Dimensions are usually wider than taller aside from when we really max it out. This vacuum issue is common no matter what the volume is at.
Batches: for any batch that uses flaked grain, we use rice hulls. Generally put some in at the beginning along with a good base of 2-row, then mix in more rice hulls with the flaked grains and the rest of the 2-row or other base malts.
Temps: mash usually 150-153 for the majority of our batches. Its single infusion so sometimes it does dip lower like 145. Sparging with 170F water.
Mash pH: 5.2-5.4
Sparge: fly sparge, try to hold 1-2” above grain bed, but with this issue the grain bed drops several inches. Gravity run off into keggle grant, then pump into kettle, generally 5-10 minutes per grant. When this problem starts, it will go up to half hour grants.
I drilled more holes into the false bottom and that didn’t make any difference.
So... any thoughts would be appreciated as we are at our wits end about this.
Cheers,
Brian
Below are the details, but what we’re mostly seeing is the grain bed drop 10” almost immediately, even with a very slow vorlauf and sparge. When it starts to slow down, we see big air bubbles go back up the hose, through the sight glass and back into the mashtun. Sometimes the run off goes completely dry, but the mash still has an enormous amount of water in it. When this has happened and we finally call it, if we start graining out and shove a shovel into the grain bed, you can hear the vacuum break up.
Mash tun: homemade 7bbl, we push 10bbl batches out of it. Dimensions are usually wider than taller aside from when we really max it out. This vacuum issue is common no matter what the volume is at.
Batches: for any batch that uses flaked grain, we use rice hulls. Generally put some in at the beginning along with a good base of 2-row, then mix in more rice hulls with the flaked grains and the rest of the 2-row or other base malts.
Temps: mash usually 150-153 for the majority of our batches. Its single infusion so sometimes it does dip lower like 145. Sparging with 170F water.
Mash pH: 5.2-5.4
Sparge: fly sparge, try to hold 1-2” above grain bed, but with this issue the grain bed drops several inches. Gravity run off into keggle grant, then pump into kettle, generally 5-10 minutes per grant. When this problem starts, it will go up to half hour grants.
I drilled more holes into the false bottom and that didn’t make any difference.
So... any thoughts would be appreciated as we are at our wits end about this.
Cheers,
Brian
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