Anyone else out there using the open-source software “Brewtarget?” It’s not bad for cheap as free! My questions involves brew in a bag users. How much grain absorption do you usually get and what value should I enter for the efficiency of this process (in general). I’m moving from extract to all grain brewing but haven’t scraped up enough green to get a decent sized kettle so I’ll be doing the biab in my 4 gal kettle. The math doesn’t seem to be working out with the values I’ve been playing with (negative wort after the boil??!) Any help from fellow brewtarget users welcome.

For BIAB 0.075 gal/lb is a standard starting point. If you squeeze hard, you can lower that. Never used BrewTarget before

Grain will absorb about 0.125 gal/lb. Assuming you’re doing a no-sparge, then the max efficiency is simply the wort in the kettle divided by the water in the mash, so for a mid-gravity batch, you should see efficiency around 75-80% (if you achieve 100% conversion).

At 0.125, you must not squeeze the bag at all.

for this first recipe I entered 0.1gal/lb. Midway between the suggestions and not absurd if you let it drain supported in the strainer while you bring your wort up to boil. I think all the math problems were solved when I remembered to scale the batch down to 3 gallons because of the full vol boil. I guess I could set up the equipment parameters to do the figuring for a top up of the fermenter, like in an extract kit, but for now 3 gals will keep me honest until I can get the hang of this setup. thanks guys.

Also BUMP for brewtarget users!

[quote=“enkamania”]At 0.125, you must not squeeze the bag at all.[/quote]Yeah, I don’t squeeze the bag and don’t sparge - grain is cheap and gravity is good enough for me.

I use BrewTarget for BIAB and I have my absorption rate set at .520 qt per/lb. I have been hitting all of final volumes perfectly. I squeeze the bag…