BIAB with a stainless steel pot on gas

[lordarpad]

Hi guys I am thinking of getting myself a BIAB setup - slowly but surely I'd like to use a 70l pot and my wok ring. The problems will of course be the hot gases that rise around the pot. I have been thinking about ceramic insulation and a way to fasten the bag underneath the insulation. Anybody have experience, thoughts?

[alealex]

Biab.. my favourite, use pot with thick (sandwich) bottom and you won't have any problems, constant stirring while gas is on would help (you're not going to burn bag).
The advantage of this system is step mashing of course!

[lordarpad]

bit worried about the constant stirring during a 60 minute boil .... not doing that with an electric one

[mr hoppy]

Take the grain out before the boil.

[alealex]

You don't need to stir during boil. only during mashing as long as the gas is on between steps (55*C to 65*C to 72*C to 78*C etc)
In other words gas on and stir till it hits certain temp. gas off stop stirring or stir every few minutes.
Turn gas on constantly after mashout and bring it to boil without stirring.
As Mr Hoppy says pull bag with grain out the pot - no stirring.

Edited now, sorry, mea culpa. It should be: you don't need to stir during boil.

[mr hoppy]

What's the idea of stirring? Is it to make sure the temp is evenly distributed?

[alealex]

Edited the mistake, sorry.

[Eoink]

I generally dont bother about insulation when BIAB. I treat it as  reverse step mashing. I start at 67C and let it fall to 63C over 60 mins. I only stir  every 20 mins  and turn the heat on for the last 15 mins to mash out. I skip the protein rest as this only helps clarity (in theory) and not the taste. There was a podcast on reverse step mashing on basic brewing radio a couple of years ago

If you use a big enough volume of water it helps retain the temperature and allows you to suspend the bag above the bottom so you dont have to worry about burning the bag.

For a 5kg of grain I mash with 21 litres.