Mash in a Bag (MIAB) Mash Profiles?

I mash in a bag (MIAB) not a full BIAB. The process is mash in the bag, drain, batch sparge with about a gallon of hot water, drain again - then let the bag drain (with some squeezing) while the wort is in the kettle and heating.

Because I let the bag drain, I end-up with about 1 gallon of wort which leads to a longer boil time as the batch is over target volume.

The BIAB profiles require approximately 1 gallon less that a batch sparge profile when playing with the profiles. I've tried tweaking the BIAB profiles to require a gallon less pre-boil but I can't get it quite right.

So, is there a MIAB profile that may do what I need OR a helpful push in the right direction to create my own?

Hope this makes sense ...

I read your post and have been sitting here trying to figure out how you end up with any more or less wort whether you MIAB or BIAB? Either way, your goal is to have X gallons of wort into the boil kettle. To get there you have to use a fixed amount of water in your mash. If you come out over, or short, then you need to adjust your strike and/or sparge volumes.

Kevin58 - I believe it is because I let the bag drain over time. In the Rubbermaid cooler with graduated markings, I net at least 1 gallon of wort > 1.040. I hate to let this go.

My options are too discard, toss it in the kettle & boil longer, or boil it on the stove & concentrate it into a sticky goo. It adds a few points to the gravity at such a high concentration.

Perhaps it's a tweak of the grain absorption since I am draining and squeezing to extract as much as possible. By the way, there has not been any tannic taste by doing so.

In BS, I adjusted the mash absorption from .96 to .568 to match the BIAB absorption and it brought the water requirements down about a gallon - just as the BIAB mash profile did.

Since this is only MIAB, batch sparge occurs after draining the first runnings.

This just may work.

I think some of the confusion comes from trying to equate BIAB with batch sparging. They are two separate techniques. Batch sparge in a traditional mash tun expects some loss that remains in the grains. I do full volume BIAB in the boil kettle. When I remove the bag I squeeze it to get every last drop. I don't count that as extra. You are using gravity to get the last of the wort out of the grain bag and shouldn't count that as extra either. Calculate that amount into your total.

Because you are mashing in a bag but using a batch sparge instead of a full volume, you really are doing a hybrid of the methods.  I do this in my BIAB set up when I have a particularly large grain bill so that the efficiency drop is negligible as compared to my full volume BIAB.  To do this, I needed to set the standard water absorption rate in the program to reflect my usual water absorption rate for my BIAB system. 

So as Kevin58 recommended, calculate your actual water retention in the grains and use that figure to get your volumes accurately predicted by the software.  In the end, it will save you a lot of grief as you try to improve your process.

With a 10 gallon Rubbermaid round water cooler, space is tight for larger beers. I cannot do a full volume mash and do not have a means to insulate the keggle.

The hybrid system works well, just need to tune-it to get the water requirements right. BS is set now with the BIAB settings for normal all grain. I would rather be low on water, adding is easy.

The keggle I mash and boil in is not insulated. I do not lose more than a degree or two during the mash PLUS the beauty of mashing in the boil kettle is that you can turn the burner on if you need to raise the temp. You probably won't have to do that more than once... twice at the most during a 60 minute mash.

My insulated Rubbermaid 10 gallon round cooler looses heat over time. How do you not loose heat from an non-insulated keggle?

I'm guessing because the keggle is made from such a heavy gauge aluminum that it's thermal mass is such that it does not lose heat as fast? Anyway, all I know is that my keggle retains mash temperatures just about as well as my Coleman Xtreme 100 qt cooler did.