Gavo
Dogwood Brews
Well I finally went and added a HEX coil to my brewery after many years of running a simple 3v rig and have come up with a curious result. Other than airlocks boilovers (due to having my back turned while efficiently cleaning while starting the boil) this one has me a little beat.
In my usual process with a double batch of 42lt using 8.5kg grainbill I mash in with 20lt of water let it rest for 90min then drain to kettle, using good old gravity (no mashout). I then follow up with a double batch sparge with a volume of an equal 20lt each. So all up 60lt of liquor volume. Once all liquor is drained into the kettle I end up with a pre-boil volume of approx 51 lt and a post boil of 42 lt into the fermenters. Usually getting close to 82% efficiency.
So yesterday I did my standard APA recipe using my new HERM's system and it gets a little interesting. I mashed in with 30lt at 60deg and ramped to 65deg. The ramp took some time due to airlocks and such, probably 20 or so minutes (I wasn't timing while undoing hose clamps etc) let it rest at 65deg for 60 min then ramped to 75deg for mashout then pumped to the kettle. Next I pumped 30lt of sparge water up fo batch sparge and re-circulated for 10 min and again pumped to the kettle. So 60lt or liquor in total, same as always, however I was left with approx 45lt in the kettle, so 6lt less than usual. I then pumped another 6lt across to the kettle to achieve my target pre-boil of 51lt. Efficiency was dead on 80% pre and post boil.
Pumping from the MLT is faster than straight draining but surely there can’t be 6lt still hung up in the grain, there would be no more than half a litre in the lines.
So the question is where did the 6 lt of water go?
In my usual process with a double batch of 42lt using 8.5kg grainbill I mash in with 20lt of water let it rest for 90min then drain to kettle, using good old gravity (no mashout). I then follow up with a double batch sparge with a volume of an equal 20lt each. So all up 60lt of liquor volume. Once all liquor is drained into the kettle I end up with a pre-boil volume of approx 51 lt and a post boil of 42 lt into the fermenters. Usually getting close to 82% efficiency.
So yesterday I did my standard APA recipe using my new HERM's system and it gets a little interesting. I mashed in with 30lt at 60deg and ramped to 65deg. The ramp took some time due to airlocks and such, probably 20 or so minutes (I wasn't timing while undoing hose clamps etc) let it rest at 65deg for 60 min then ramped to 75deg for mashout then pumped to the kettle. Next I pumped 30lt of sparge water up fo batch sparge and re-circulated for 10 min and again pumped to the kettle. So 60lt or liquor in total, same as always, however I was left with approx 45lt in the kettle, so 6lt less than usual. I then pumped another 6lt across to the kettle to achieve my target pre-boil of 51lt. Efficiency was dead on 80% pre and post boil.
Pumping from the MLT is faster than straight draining but surely there can’t be 6lt still hung up in the grain, there would be no more than half a litre in the lines.
So the question is where did the 6 lt of water go?