I have been doing some batch sparging with the Denny Conn method, and it works great! I also wanted to try, in the days that I want a slightly shorter brew day or a smaller experimental recipe, a BIAB. I have listened to a bunch of podcasts about BIAB and really it sounds like a nice alternative for quicker brew sessions. I was wondering if anyone out there has tried medium to bigger beers and where they start to see efficiency issues. Really I am curious about all these points:

  • Does your efficiency suffer at all?
  • Is there a limit of what you can do for styles of beers?
  • How big can you go? I know you have to have a pretty big pot as the grain goes up, but does your efficiency suffer greatly just because it is BIAB?

Thanks again for all of your help and input!

  • My impression of a BIAB was to just add some flavor from the grain, then get all your fermentables from extract. I'm curious how far someone's pushed this.
    – fire.eagle
    Mar 28, 2012 at 20:53
  • 4
    @fire.eagle BIAB is a full mash technique no extract is needed when done right. I think you are thinking of partial mash.
    – brewchez
    Mar 28, 2012 at 23:30

2 Answers 2


I have been doing mostly BIAB for my last three batches of beer. I got pretty good efficiency, about what I have gotten on a batch sparge. I do squeeze the bag and haven't bothered to try doing any sort of rinsing.

As opposed to brewchez I find that doing BIAB does save time. No time setting up the mash tun or cleaning it. No time spent sparging. Go straight from mash to boil. Don't get me wrong still takes more time than extract, but it definitely saves some time.

As for the bag size I have a 10 gallon pot and I designed my bag to fit in that and did kind of an x pattern on the bottom so that it lays more flat, to give the grain in the bottom potentially more surface area to spread out.

As for styles I have so far done:

  • Two pale ales (~5%)
  • Belgian golden strong ale (7.7% ABV)
  • Weizenbock (7.7% ABV)

As for the size of the beer I decided to push the envelope and go for a 7.7% ABV Belgian Golden Strong ale. Got pretty much exactly the efficiency I expected (~65%) and an excellent tasting beer to boot. Then decided to try out Jamil's weizenbock and it turned out pretty good as well.

I say go for BIAB, it gets a lot of flak. But I think it is pretty awesome, especially for someone who lives in an apartment and doesn't have the space for a full batch sparging setup.


I have done both, and BIAB isn't any faster than batch sparging. The only difference is less equipment really. BIAB is all in one pot and not cooler or mashtun. If you put your first runnings in the kettle and start heating it the next runnings are ready to add long before it comes to a boil. You add them and you are in the same place as with the BIAB at that point.

Answers to the questions: 1. Efficiency does suffer a bit, but its managable. Its a little different for everyone depending on whether you rinse the bag a bit with water, or choose to squeeze it or just choose to let it drip. 2. All styles are fair game, its mashing just in a bag. It might be tough to get a high gravity wort of say 1.090 in one mash session though due to absorption losses. 3. You can go as big as a bag you can find as long as you have a way to lift it out.

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