Well, I had a good practice run of this, I guess.
I mashed about 11.5kg of grain and .5kg of flaked wheat and .25kg of rice hulls. I had just replaced my stainless braid with a 3/4" hot water heater braid supported inside with a coil of copper wire.
After an hour, I tried to vorlauff and all I got was a trickle. I emptied the mash tun and added some holes to the braid, but not much luck. It would have taken hours to sparge enough for the 10 gallon batch I was doing.
I have to brew this again in a couple of days when I replace the braid with a smaller version like I used to have.
Any body have any insight for me? The crush looked good, the mash looked great. All I can think of is that the braid must have been too tight to let the wort in fast enough.