Excuse my ignorance of fluid physics but I wouldn't have thought that a 'T' shaped manifold exactly conformed to the tried and true principles of manifold design. A manifold should have an equivalent flow rate from all parts of the mash tun - the manifold you have made there is certianly going to create isolated pockets of flow.
The standard procedure when using termimesh type products is to have a copper 'T' piece extending part way into the mash tun with a coil of hose coming off each end of that. That way, the distance from the sides of the tun to the manifold is equivalent all the way round.
its weird hey pumpy.ive used mesh for ages no probs.im now using braided line and find once again no probs.only have had one stuck sparge and that was with heaps of wheat.for what it worth though pumpy make sure the mesh/braid is thoroughly cleaned as small amounts of grain husk will slowly but surely build up and block those small apertures impeding flow.
"Excuse my ignorance of fluid physics but I wouldn't have thought that a 'T' shaped manifold exactly conformed to the tried and true principles of manifold design. A manifold should have an equivalent flow rate from all parts of the mash tun - the manifold you have made there is certianly going to create isolated pockets of flow. "
Whilst this is true for fly sparging, it is irrelevant if Pumpy is batch sparging. What system do you use? Ie batch sparge, mash out etc
I misinterpreted what you were saying previously. My belief is that the tried and true manifold design is as such because they are trying to gain an efficent system in rinsing the sugars from the grain ie to prevent channeling etc. Whilst manifold design would impact whether compaction occurs, this for me is not a primary focus of manifold design.
In this case i can't figure out pumpys problem until he states whether he batch or fly sparges. Overall though you are correct that both will cause localised compaction, batch sparging moreso if the sparge is done quickly.
Sorry Guys I am batch sparging ,when I adjust teperature in th e Tun ( picnic cooler ) by adding more hot water ,I think I am compacting the grain bed ,when I removed the grain the T manifold was clean not jambed up so I am thinking I may have too much water in the tun .
Pumpy, I batch sparge with an easy hooker stainless manifold. The first time I used it everything went fine but the next time she stuck. And the time after that. What I found was to put the manifold into a grain bag secured at the outlet & after that the sparge has never stuck. Can't really see why it doesn't work by itself but I tried again yesterday without the bag & sure enough she stuck again. Emptied the mash tun, put the manifold in the bag & everything went like clockwork again.
This is pure speculation, but from what you guys are saying for a mesh style manifold to work, perhaps there needs to be some sort of resistance when the wort flows through. For example people with SS braiding, and those who use a manifold and grain bag as well, have less problems with a stuck mash. I can't really think why this would be the case.
Perhaps the mesh used in the manifold, lets the wort through to quickly due to it being highly open to letting wort through, so that it means the mash plugs itself harder into the holes, as it allows a higher flow through the holes
It could be more to do with the crush. I don't have a mill & so get my grain crushed at the HBS which uses a grinder & I wonder if that creates a bit more flour that clogs up the mesh. The HBS is getting a new roller mill soon so that should give me the answer. The other thing I found was to start the runoff slowly. That seems to let the grain bed pack better & after a couple of minutes I can open the tap a let it run faster.
Yesterday I replaced my false bottom with a stainless steel scrubbing brush. Given that I was batch sparging, it did an absolutely fantatsic job. Quick, easy and cheap. If anyone wants a false bottom to suit a 20L rubbermaid, you can have it