In one of my articles, Creating a Mash Tun False Bottom Gasket, I attempted to modify my mash tun to eliminate stuck sparges in my own brewing process. Although the gasket solution solved the problem of the mash seeping past the sides of the false bottom, I was still getting too much grain under it. It wasn’t an issue with the gasket, but it’s a flaw in the false bottom itself: the holes in the bottom were just too large and the grain was getting through.
I only encountered this problem if I thoroughly stirred the mash, which is something you’re going to need to do quite often. So avoiding stirring was not an option. I had to rethink the problem.
Modifying the False Bottom
To correct the basic design flaw of the false bottom, I had to resort to buying a stainless steel (SS) wire mesh that I got through a friend. Finding the SS mesh may be a little difficult, but if you can get your hands on some of this stuff it’s great to have on hand. (You can also use it to create a hop filter for your kettle.)
Adding the SS mesh was straight-forward. I simply cut a piece that was more than large enough for the false bottom and cut another hole in the centre where the dip-tube goes through. I then cut the mesh to match the circular structure of the bottom and wrapped the mesh tightly around it.
Wear gloves when you do this because the tiny wires of the mesh will surely poke holes in your skin, and it’s virtually unavoidable. You were warned.
Once I completed the alteration, the stuck sparges were finally a thing of the past. I still have to be careful not to let the mash sit too long because if I do, it becomes too compacted and the wort just doesn’t come through. Also, the sugary wort will become congealed at lower temperatures so keeping the viscosity of the wort intact is important. Ensuring that the wort is at mash-out temps (or close to it), giving the wort a stir, waiting 10 minutes and then going through my lautering process showed that the design worked very well.
The one down side is cleaning. It’s a bit of a pain because you have to take most of the stuff apart to get everything really clean. It’s a price that I’m willing to pay for a care-free brew day.
Common Causes of Stuck Sparges
- Faulty equipment, as in my case;
- Crushing the grain too finely;
- Wheat recipes commonly create stuck sparges. You need to use about 1 lbs of rice hulls to create channels for the wort to flow through the mash;
- Allowing the mash to settle for too long. This compacts the grain bed and stops the wort from getting through;
- Low mash temperature. Wort viscosity will be reduced as temperatures drop. Sparge at mash-out temps.