Grainfather mash issue

[xozzx]

I have started milling my own grain and have started having an issue with the mash. It might not be related to the milling as the brews I made recently have been high ABV and close to the grain bill limit of the GF.

All starts off very well, then after around 45 mins I start getting wort going down the overflow pipe. I suspect the top plate has dropped as the liquid level actually looks lower from the top of the GF. This results in some bits of grain getting into the boil. I am getting a decent sparge after the mash.

Any advice appreciated.

 

[chewie]

Is your grain crush at the optimal setting for the GF?

When you fill the grain basket it's best to start with any coarse grains first, things like flaked barley act like a large filter, gradually work up to the finer grains last like rye, do stir well as you add but try to leave the bottom layer alone.

Don't press the top filter plate down to much onto the grain and run your pump flow rate slow to start with, increase it up to the point just before wort runs down the overflow. If it should happen again stop the pump, lift out the top plate and stir the grain.

 

[xozzx]

I have the gap set at 0.9mm, not sure if this is the optimal gap for GF...

I find that the recirculation pipe pushes the top plate down, Im tempted to cut it a little shorter as it usually pushes down on one side of the plate.

Next time I will try stirring the grain if it drops again, that should help with raising the level a bit.

Cheers

 

[Norfolk79]

I always have had wort going down the overflow pipe during the mash. I just leave the pump alone and don’t throttle it back at all.

Think from memory I’ve set my gap on my mill at about or just over 1mm.

 

[chewie]

If IRC the recommended gap is around 1.2-1.4mm, .9mm is on the fine side, fairly sure the exact size is up on the GF site.

The recirc pipe shouldn't be pushing on the top plate with any force, just let it bend without kinking and lie on the top of the plate.

There are several reasons I don't like the overflow being used.

If it's left overflowing all the time you don't know if it's stuck or not.

Grain that ends up either falling thru the bottom plate or has went into the kettle when filling the basket can be left on the top plate if recirculated and isn't left in the wort during boiling which reduces any chance of scorching.

 

[xozzx]

Just checked this link and mine looks more like the 3rd picture "a very fine crush". Ill try about 1.2mm for the next brew and see how I get on with that.

 

[Saisonator]

I always use rice hulls, with the amount depending on grain crush and type of grain.
I also start the flow slowly and gradually increase but as long as I can tell that most of the wort is flowing through the grain and not down the overflow then I increase it normally to full flow.
I normally give it a stir half way through, although if it is really flowing well I may not bother.
This type of system really needs the correct grain crush.

 

[Bigcol49]

Hi!
Try malt conditioning. It allows you to mill "tighter" without compromising the grain bed filtering properties.