What is brew in a bag? aka BIAB

What is brew in a bag (BIAB)? I’m not about to go deep into the science and chemistry here, I just want to touch the surface, get to the basic concept of BIAB. Define it. The way I see it, there is only one true definition for BIAB:

Brew in a Bag is a brewing method that uses a porous “bag” for lautering (separating wort from grains).

That’s it. There are so many variations that can fit under this definition and each and every one of them is still BIAB. Any further restrictions on this definition and you leave out a process somewhere that should be BIAB. This will get a lot of 10th level BIABers riled up, but it is the truth. They’ll want to box BIAB in to using only 1 vessel and require you to use all your water in the mash amongst other things. That simply isn’t true. Think of the parallels to BIAB: fly sparge, no-sparge, batch sparge…what is the common denominator? Separating your wort from the grains. Some are slow, some are fast, some use all the water for the batch, some use some of the water for the batch, some use two vessels sometimes, some use three vessels sometimes, etc. Lots of different ways to lauter even within the same method. As an exclusive BIABer for just short of two years now, I vary my brew day process all the time either out of necessity, or just to try something different. Yes, there is a basic method that I use most of the time, but I do not fret about deviating from it. Why box yourself into a tight definition?

Did you notice that mashing is missing from the definition? The bag isn’t important to the mash, it’s just there waiting for the lauter. You put the grains into the bag then mash because you couldn’t mash then put the grains into the bag…..or could you? Ahah, now you see why mash isn’t in the definition. There’s no reason why you couldn’t do your mash in a whole bunch of small pots and pans in your oven to keep them warm then dump them into your boil kettle that has your bag in it, right? Or maybe you’d like to use a super insulated cooler to hold your mash temps then dump the whole thing into your bag in the kettle, why not? If you think about it, the BIAB parallels equipment aren’t important to the mash either. Some brewers use a separate mash tun and lauter tun but could still be a fly sparge, no? False bottom, or under drain in a cooler, still a batch sparge, right? See? We’re really talking about lautering here.

Vessel 1..2..3
You hear that using more than one vessel complicates the process so it isn’t real BIAB because it has to be kept simple at all costs! Many BIAB purists go nutty about the number of vessels thing, more than one and it is too complicated. Hogwash, use whatever number of vessels you want or need to. One is the minimum required, that’s it. Sometimes I use one, sometimes I use two, or go really off my rocker and use three! Who cares?

You hear that if you sparge your bag by trickling water over it or dunking it in mashout temperature water you’ve complicated it too much and are wasting your time. Many BIAB purists insist you must use all the water required for your brew in the mash. Phooey, use as much of your brew water as you want or equipment restricts you to. Full water volume mashing is indeed the easiest method, but it really isn’t hard to reserve some of your water for later processes…just watch out, you might have to use an extra vessel! (the HORROR)

Whatever you do, don’t point out that BIAB is like No-Sparge brewing, that will get you kicked out of most BIAB purist clubs for sure. Never mind that at the simplest form with full volume of water used in both methods, the only difference is the lautering. With BIAB it is accomplished by removing the grains from the pot and letting the wort flow back into the boil pot. With No-Sparge it is accomplished by draining (usually rapidly) the wort from the grain through a bottom drain into the boil pot. One advantage of BIAB (and a difference) is that by pulling your bag up, the grains get a bit of a squeeze while it drains, so by just doing the basics, BIAB should get a few more points of efficiency than No-sparge. But I bet if you emulated the squeeze of a BIAB in a No-Sparge mash tun by pushing down the grain bed slightly, you could easily get the same efficiency. Remember above where I said you don’t have to use all your water in the BIAB mash…sounds just like No-Sparge where some people do and some people don’t doesn’t it?

Mash out
Mash out or not? Another fork in the road, follow many BIAB purists and they’ll tell you that a mash out is a waste of time. Others will tell you a mash out is really worth it. Who is right? Both and neither! Do what you want to, the differences are small and the effort is too.

Squeeze or no squeeze is another topic that can get many BIAB purists wound up. For some people it is worth it, for others it isn’t. For me, it is about consistency. I press my grain bag against a colander in an extra kettle, and twist the bag to get as much as sensibly possible and this gives me pretty predicable results. That’s what really matters isn’t it? I mean predicting your results and meeting them should be held higher than worrying that you may be “complicating” things too much by adding a step to your process.

Why is bag in quotes? Some people use metal buckets with holes or cylindrical screens in place of bags. Why not something like a zapap ala Papazian? Nobody said it had to be fabric.

What about volumes? I do 5 and 10 gallon batches outside on my turkey fryer burner with my setup. I could shrink things down and brew 3 gallons on my kitchen stove using a small pot. I could mash a lot thicker and get a concentrated wort that I dilute down or even add extract to like a partial mash (like? wouldn’t it actually be a partial mash? Remember, the lauter is what matters!) I could use my setup to get a wort concentrated enough to dilute down to 20 gallons or more. You could do all grain partial boil on the kitchen stove with a small pot. Like everything else so far, there are many possibilities.

Don’t restrict yourself with a tight definition, keep it basic. Think of BIAB as a lauter method.

Agree or disagree? I’d like to hear it. Maybe we can all learn something or see something from a different viewpoint.

Stay tuned for more informational posts. I learn something when I start thinking and writing about these things.

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