Everywhere I see conversations about BIAB, people are always referring to nylon or polyester bags. Why can't one use, let's say, a cotton bag, since it will be so thin it won't hold any water?

  • 1
    This is one of my concerns with attempting BIAB. Maybe I'm paranoid but I'm not a fan of heating plastic that comes in contact with things I'm going in ingest.
    – Mattress
    Commented Mar 4, 2011 at 17:06

3 Answers 3


I think flow through a cotton bag, like a pillowcase (?), would be so slow it would be time prohibitive. Cheese cloth or hemp may be a natural alternative.

  • When talking about a cotton bag, there are not just two grades of thickness:cheese cloth and "pillowcase". I just bought a cotton bag that is somewhere between the two, I'll tell you the results after I use it a few times. But the point is this answer is not about material, but about thickness. My question is about the opposite. Commented Apr 21, 2010 at 17:26
  • Yeah I don't know why I assumed cotton couldn't be woven into something more porous. Pretty lame answer on my part. I'd be down voting if I could for my own answer.
    – brewchez
    Commented Apr 22, 2010 at 12:45

It is not a bad idea to check the material's resistance to heat and how it reacts but we are not talking about boiling the bag. Most people mash around 150 F and maybe do a mashout to 170 F so the bag will never reach 212 F.


Synthetics are generally used because they're "inert" and don't affect flavor at all. Since the fibers also can't absorb any liquid, the porosity of the bag won't change like it would with hemp or cotton.

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    The specific material should still be checked that it's food-grade and safe for boiling temperatures. Many "soft" plastics contain chemical conditioners which can leach at high temperatures. This is a topic wihtout much objective information; however a good rule of thumb is to make sure you're using the product (bag) in an approved way. If it doesn't say it's safe for boiling, then it may not be
    – STW
    Commented Mar 2, 2011 at 21:46

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