I tried for the first time using the BIAB method and ran into a big problem with the mashing bag.

I placed all the ingredients (9lbs of different grains) in the mashing bag without thinking of the weight problem/absorption.

I was unable to remove the bag from the pot - it was just too heavy and it had absorbed 3/4 of the wart (5 gallons).

What did I do wrong? Is my mashing bag too fine? Was I suppose to mash small amounts of grain instead of all at the same time?

2 Answers 2


Sounds normal to me. When I was first reading up about BIAB, it was mentioned in several places that this is an issue. Absorbing 3/4 of 5 gallons seems like a bit much, but it will absorb some (I've heard about a quart per pound?). It probably didn't absorb that much, as the wort would drain out of the bag if you could hold it over the pot for 10-20 minutes.

I've adapted my technique for BIAB over a few batches. These steps are my version of merging BIAB with all-grain and sparging, and helps with this issue. I've used this technique with all-grain recipies, and associated water temperatures for mash and sparge, and it turns out great.

  1. Don't start with all the water in the pot. Then if you need, you can take the pot down on the floor to get over the bag to lift it.

  2. Put down towels when removing the bag. It drips... a lot.

  3. I got some buckets from WalMart, drilled holes in the bottom of one, and put the grain bag in the drilled bucket, and then that bucket into a second bucket. This will let it drain without having to hold it up the whole time. If you can get the pot on the floor, then just stand over it with the drain bucket right next to it. Then just lift, pivot, and lower the bag to start draining. Have an extra catch bucket ready for when the first one starts getting full. (Also helpful for the next step.)

  4. After not having used the full boil volume in the pot, we need more water. I heat up another few gallons, and begin pouring it over the grain bag in the fermenter bucket. The fermenter bucket is big enough to hold the extra volume you'll be pouring in there. This serves to rinse more of the sugars out of the grain, while topping off the volume. (This is my version of sparging.)

  • I like the drilled bucket filter idea. Will probably use this next time we brew. Jul 21, 2014 at 23:34

I overcame this problem by replacing my BIAB bag with 4 paint strainer bags, putting a quarter of the grain bill in each, and sealing with plastic zip ties. Put one bag at a time into your kettle, ensuring that all the grains are exposed to the water. Give the bags a stir every 15 - 20 minutes until mashout. Quite easy to remove one bag at a time, draining each one for about a minute.

You may need to adjust your water strike temperature upwards a degree or two, as it will take you five minutes or so to ensure that the grains in each bag have come into contact with the water. Works great for me, and for bigger beers you can always use an extra bag.

Got this idea from a Toronto homebrew site in Canada, Schoenwetter Brewing, I think.

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