When I've been within 8-10 litres of the final volume in the boiler I've turned off the sparge water and let the liquor in the grains drain through. This gives me almost completely drained grains and the volume I want in the boiler.
But a couple of brews ago the run off from the boiler stuck. I had to pull the hop filter out, clean it, and replace it. The wort eventually got to the fermenter, but it was really slow.
This was using Maris Otter from MM. So I contacted Rob and asked for advice. He kindly contacted Fawcett's with the photo I sent him.
This is where it gets interesting. I'd assumed the stuff bunging up the filter was trub. I've always had this sort of deposit at the end of draining the boiler, just never enough to block the hop filter. Always assumed it was trub. How wrong was I? Fawcett's said no. It was flour from the malt. Well, knock me down with a feather.
Fawcett's suggested this could happen if the grains weren't kept floating. They didn't know my sparge technique when they suggested this, but the problem was one they recognised. By draining the mash tun the grains can compact down and cause this to happen. Can't quite get my head around why this would be the case, but Fawcett's clearly understand why.
Rob also suggested the grains may have been crushed slightly more than usual, which would give more flour. It all began to make sense now.
So, the following week I brewed again. The grain bill was exactly the same, and the MO was the second 5kg bag I'd bought at the same time as the other. Presumably identical.
The sparge liquor was kept running all the way through, which meant there was a good 10 litres to drain off the tun after the pre boil volume had been reached.
The result? Good run off from the boiler and a completely different presentation of the residual hops.
Many thanks to Rob for helping me sort this, and to Fawcett's as well for taking the trouble to reply.
Perhaps everybody sparges like this, and I'm just late to the party! No going back now, though.
- problem sparge with flour.jpg (4.32 MiB) Viewed 1483 times
- clear sparge.jpg (3.6 MiB) Viewed 1483 times
Guy