I have now done this method 3 times, and it is easy as and the quality is great and worth the extra time.
Following Nick JD's advice I bought a coffee grinder to get a consistent mill and take it to a fine powder.
However, when I add the grain once at strike temp I am getting heaps of dough balls! I think it takes me about 5 mins to get rid of them all.
Am I grinding too fine... or is this the norm? Trying to mash all the balls out has reduced my mash temps a little, but as I am still learning the AG caper I am not that fussed and have been hitting close to the numbers I want.
Is there a technique to be used when adding this finely ground grain - I have been adding it all at once.
Cheers again, I am hooked on AG now!
Here's a way to sort out an extremely fine mash and dough balls.
Fill up only to about 8~9L with just hot tap water, put in your bag and then dump in your grain. You should end up (of course this depends on your hot tap water temp) with about 45-50C mash.
This is below the temperature that the starch will dough-up, so you just get a nice thick, slippery porridge.
Put 2L of water in the coffee kettle and boil it. This will give you about 52-55C when you add it (while stiriring). By the time the kettle has boiled again, you've done a few minute protein rest.
Add the next 2L and you'll get up to ~62C. You can leave it here if you want a dry beer, or you can add another 2L and get up to ~66C. You've probably hit the rim of the 19L pot about there.
This will both eliminate doughballs, give you a wicked efficiency and give you most of the benefits of an stepped infusion mash ... just gotta boil the kettle 3 or 4 times.
Alternatively, get your HBS to mill your grain or cough up a few hundred for a mill setup.
I infuse often (usually 45C, 52C, 60C, 64C) because it makes a better beer. Dry with head-retention.
Once you work out your gear you can put the lid on in these periods between adding the next kettle and do a full on stepped mash. Takes notes and refine. Google "Hochkurz mash".