So my last couple Brew days I’ve been having a problem when lautering. I’m using a 10 gallon picnic cooler mash tun into an 8 gal boil kettle.
After my mash is complete I recirculate the wort into a two quart container and I have no problem getting clear wort. I attach my tubing to the ball valve and when I start to lauter I’m seeing grains coming through the tubing. But if I take the tubing off and drain this way I get no grains. What about the tubing could be causing the grains to come through? This past Brew day i gave up and just drained without tubing risking hot side aeration.
The hose makes the flowrate increase. Presumably the higher flowrate pulls in more debris. Perhaps you should vorlauf with the hose on.
I had a similar problem in that no matter how much I vorlaufed I could not stop the occasional chunk of husk from getting into the boil pot. It turned out I had a “leak” in the lauter manifold which allowed the chunks through. The leak was bigger than the slots in the manifold. Once I fixed the leak, the problem went away.
A few husks and even a lot of husks is often no big deal. There is a recent xbeeriment thread about this.
I assume that hose is hanging down from the outlet? If so, the hose is placing an extra bit of suction on the internal piping since the end of the hose is at a lower elevation than the plain outlet. That extra suction is probably getting the wort to flow faster and draw grain through the screen.
By the way, this is the reason that old time mash tuns had gooseneck taps on the outlets. It helps reduce the head difference and avoids placing too much stress on the grain bed due to higher than appropriate flow rates. If you raise you tube outlet elevation, you will achieve the same result.
You might try vorlaufing with the hose attached the entire time. That way your grain bed is getting set at the flow rate at which you will be filling your kettle. Its the change in flow rate that is likely disrupting the grain bed and sending some out of the MLT.