BIAB Recirculation method?

As far as recirculating during the mash is concerned, does it matter what pattern the wort renters the kettle (i.e. is there any advantage to having it recirculate through a sparge arm vs a 1/2 inch silicone tube)?

I feel like a wide dispersal pattern would yield better efficiency, but then again the mash might be so thin that it doesn't really matter. Thoughts?

I'm interested in the opinions on this as well. With that thin BIAB mash I don't really understand why there is a need at all to recirculate? Why not just stir it once in awhile?

I've been thinking about this as well. I'm planning an eBIAB setup and I want to recirculate to help maintain a constant temp in what is a pretty thin kettle. I've seen some people just dump it in through a hole in the top of the kettle. Other people who have just ran the hose back in to the wort. I was looking at sticking this sanke adapter in through the top of the kettle, attaching it with a locknut and hooking it to the return hose with a blichmann quick disconnect.

http://www.midwestsupplies.com/sanke-adapter.html

It would be right at about the wort level I think. I was wondering if I could use this for a little hop whirlpool at the end too?

What type of pump do you use for this and what efficiency gain can you expect? I know it matters on the setup, but with a full volume biab with no sparging, I have been getting low 70% I would love to get it up to 80% if I could

This is the main inspiration for what I aim to accomplish with my eBIAB setup. https://www.homebrewtalk.com/f170/110v-recirculating-ebiab-2-5-gallon-batches-341219/

People on that thread that have done it say they have gotten about 80%. I'd be happy with anything around near that.

Here is the pump that I just got: http://www.ussolarpumps.com/onlinestore/index.php?main_page=product_info&cPath=1_22&products_id=32

The only catch is that I bought it before it went up in price. I've used it once and it works fine enough. My efficiency was pretty low even with it because I didn't boil off nearly enough so I can tell how well it helped.

With any mashing system your crush will determine what efficiency you can get. In a conventional mash tun the limit is when the crush becomes so fine that you cannot get a grain bed filter and get a stuck lauter or sparge. When you BIAB, the huge surface of the bag is the filter so you can crush or grind the grain pretty fine and you can still squeeze the wort out of the bag.

Your mash should be the full volume of the water for the brew so the mash is pretty liquid. All that you need is to make sure to stir in the grains sufficiently to break up any dough balls. That puts all the grain particles in contact with the water and you get conversion.

I don't find any need to heat my BIAB pot once I mash in. With that volume of water there is a large thermal mass and even with a thin wall aluminum pot a couple towels wrapped around it will keep the temperature pretty stable while conversion is happening. With the grain crushed so fine, conversion doesn't take too long either. I see evidence of conversion in about 15 minutes and others have reported that they only mash for 30 minutes with good results.

I am recirculating for temp control and to whirlpool/chill after the boil. It sounds like the mash is so thin it does't really matter how the wort gets pumped back in. So I will just use the whirlpool inlet.

There is a good video here of a recirculating system. Click on the video tab. It looks like they use a spray head.

https://www.highgravitybrew.com/productcart/pc/BIAB-Electric-Brewing-System-269p3987.htm