Robobrew/all in one overflow - why not?

[Consett26]

I have a Robobrew but I guess the same (probably daft) question applies to most all in one systems.

I've seen loads of posts here and elsewhere saying that the recirculation flow rate should be adjusted so that wort doesn't go down the central overflow. That kind of makes intuitive sense - if its an overflow then too much is being supplied and the rate should be slowed, but is that actually correct in the specific circumstances? Yes, the flow rate is too high but so what? As long as the overflow cone is in the right place (i.e. resting on the top plate) who cares that the excess overflows? The top plate will still be covered in a couple of centimetres of wort, which will be percolating through the grain bed at the same rate as intended. What do I gain by ensuring wort doesn't go down the overflow?

 

[Benfleet Brewery]

I set my Brewzilla so there is a slight overflow. Not too much so as to potentially wash rouge grains down it, but enough to pump more wort from the bottom to the top keeping temperatures more even.

 

[AdeDunn]

Because it's pointless having it so high that it overflows. The point is to circulate the liquor through the grain, any that is overflowing isn't doing this, so you may as well turn it down a bit and nullify any risk of grain particles getting recirculated.

 

[Consett26]

Thanks for the replies. The consensus seems to be that there is a risk of grain particles being recirculated, although I'm not sure why that would be an issue; because it might block the pump? In my set up the grains would be prevented from recirculating by the small sieve sitting over the pump inlet. I think I'm inclined to set the pump at around halfway, knowing that it will probably overflow because that will allow me to forget about it for an hour or so and get on with other stuff.

 

[The Baron]

Because it's pointless having it so high that it overflows. The point is to circulate the liquor through the grain, any that is overflowing isn't doing this, so you may as well turn it down a bit and nullify any risk of grain particles getting recirculated.

Exactly Ade

 

[chillipickle]

I never use the overflow, you can either cap the center tube off or remove it completely and use a ss bolt to go in place of the over flow tube.

If you have trouble with good flow rate you can always throw in a couple of handfuls of rice or oat husks.