BIAB Bag Materials/Design - Pros and Cons

Post #1 made 9 years ago
I just read a post that dick kindly wrote here in the My First Post! - Post here to become Fully Registered thread.

You often see questions on other forums as to what materials are good for BIAB. Brewers ask whether they are food-safe, at what temps they melt, how long they last etc, etc.

dick always does great posts and I am hoping he will post here but if anyone else has any feedback on BIAB bag materials they have used or are using, please free to let us know how they have or are working for you.

The original bag I had my pensioner neighbour sew up for me about four years ago* is still going strong and is now used by another brewer. This, and my current two bags show no sign of wear. They are all of polyester but I hear of some brewers doing well with natural fibres such as cotton so it would be great to hear from them.

Cheers,
PP

* The rumour that my neighbour sewed up my BIAB bag purely in exchange for sexual favours is totally false :evil:
Last edited by PistolPatch on 23 Nov 2010, 22:16, edited 5 times in total.
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Post #2 made 9 years ago
I wrote in the post that PP gave a link to that I work for a textile manufacturer so now I get to be the go to guy for bag material questions. No probs PP - I will help if I can. I should mention that the textiles I deal with are not for clothing or domestic applications like curtains or shadecloth, but they do act as a filter which is a bit like what we are doing with BIAB.

The most common questions I see about the material are what kind of material, what is the melting temperature and how sheer should the fabric be.

Firstly, the standard material that most bags are made from is called swiss voile and this is made of polyester which has a melting point around 250 degrees C, so most people aren't going to run into any trouble there. People also ask if cotton is OK and I think it is. The material shouldn’t be hard to find at any large fabric store. No matter what material you use I recommend putting the bag in boiling water for 10 minutes before using it the first time to wash of any residual chemicals. With all bags you should give them a clean out after using and let it dry completely before storing it – you don’t want to have any yuckies growing on the bag. I just rinse mine out in water, others throw them in the washing machine.

The material is strong enough for what we are doing with it and you should be more concerned about the bag breaking at the seams than the material itself. My bag is double sewn at the seams and it’s holding up pretty well after 20 batches.

The openness of the fabric is a hard one to explain. It needs to be open enough to drain fairly freely but not too open that it doesn’t hold anything in. The material is quite sheer. For example, it is easy to read a newspaper if you have the material covering it.

Anyone have questions or anything to add?

Cheers
Dick

Post #3 made 9 years ago
Good bit of info Dick.

My bag is swiss voile and I hand stitched it myself (quad stitching cos I don't trust my sewing skills) with normal cotton thread. Most people would recommend using polyester thread. My bag has done over 80 brews and the first seem is still holding (lucky me) so what would you recommend using to stitch our bags?
"It's beer Jim, but not as we know it."

Post #4 made 9 years ago
My wife, the seamstress, said polyester upholstery thread :)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #5 made 9 years ago
Stux missus has the right idea but I just used ordinary cotton thread. I forgot to mention that I overlocked the edges as well as double stitching it. The overlocking stops the edges from fraying.

Material for bag - how will this work?

Post #6 made 9 years ago
I picked this up today from Joann Fabrics, Swiss Voile. It's finer than I thought the bags were supposed to be, but water goes through it quite well and I keep reading about Swiss Voile as the right material for a bag. What do you guys think?

Shown on top of a US penny for scale:

Image
Last edited by natept on 29 Nov 2010, 12:17, edited 5 times in total.

Post #9 made 9 years ago
Natept

I bought the Joann fabrics Swiss voile also. My better half doubled the fabric and reinforced the seams. I have been using the same bag for years. We made extra bags for replacements but the original bag is still going. I did burn the bottom and caught it on the temperature probe but I don't want to quit on a friend.
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Post #10 made 9 years ago
Here is a picture of the material that has been working for me. It was recently on sale so I bought enough to make the tapered design so maybe I can stop getting a small amount of wort down the side of my kettle.
BIAB_Material.JPG
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Last edited by CanBrew on 03 Dec 2010, 13:11, edited 5 times in total.

Post #12 made 9 years ago
I think he might mean like in the link on this thread.
Last edited by wizard78 on 03 Dec 2010, 19:40, edited 5 times in total.
[center]"All right, brain. You don't like me and I don't like you, but let's just do this and I can get back to killing you with beer."
[/center]

[center]Homer Simpson[/center]
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Post #13 made 9 years ago
Yes I did mean that other post.

I was just looking up the topic when you scooped me Wiz. You are quick on the draw. Thanks.

I think the +/- 15% guideline seems worth making a new bag to give it a try.

Post #15 made 9 years ago
Great photos natept and CanBrew! I haven't been able to do quite so well...
Image
You can see something a little different with my material. There is some twinning in the yarns running up and down the page. Twinning is where yarns are grouped together in pairs a little bit and the distance between these two yarns is slightly less than the distance to the other adjacent yarn. Doesn't mean anything at all for brewing but it is interesting to see that what is sold as voile does differ from place to place as the other photos don't show this.

natept's picturs shows 59 yarns across the penny, which I worked out to be about 31 per cm. CanBrew has about 33-34 yarns per cm. My material has 36 per cm in one direction and 29 per cm in the perpendicular direction. Again, doesn't mean much for our purposes as they are all in the right ballpark.

Cheers
Dick
Last edited by dick on 04 Dec 2010, 20:23, edited 5 times in total.

Post #16 made 9 years ago
Thanks for the pics guys.

dick, that is the first post I have ever seen done on BIAB material that actually puts measurements to the material. Great post mate! Thanks for taking the time to do the counting and explaining :salute:.
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Post #17 made 9 years ago
I started off with a muslin bag made by my daughter because, like others I have read of, the salespeople at Spotlight told her that they didn't have swiss voile and that muslin was the go. It worked until I ripped it on my third brew, but it didn't seem to want to sink to the bottom of the urn. I had to try to push it down with my paint masher and that is probably how I got it caught on the boil dry safe sensor. Sent her out again and told her to try the curtain section and sure enough there it was. I used the new bag today and it was so much easier. Go the voile, and you should all have a daughter like mine!

Post #20 made 8 years ago
Hi I am thinking about a bag for my brewpot and have issues with a thermometer probe – I presume it will catch on the bag as I’m pulling it and rip a hole.
Thermo probe is 33cm down from top of pot and sticks out 14cm. (pot is about 50cmx50cm)
I could make a shortened bag that sits in top half of pot only – I would lose mashing volume here and lose efficency maybe? A member of the forum suggested this as a possibility.

Or make a probe guard that will allow the bag to slide and not get caught. My idea is to get 2 cheap ss sieves. Cut out sieves from surrounds so I just have the fine mesh and flatten one. Join them together at edges and cut hole in middle of flat one so that it fits over probe and is fastened into place with original probe securing nut.
Any input into whether this would work would be appreciated.

Thanks
Ian
On Tap: Pale Ale
Fining: Bombay/Punk IPA
Next Brew: Munich Helles
Planned: Doppelbock

Post #21 made 8 years ago
Hi there Ian,

Electric BIABrewer's have this same problem with their elements. Hopefully one of them can give you some ideas. I definitely would not shorten the bag as it will almost definitely cause some sort of inefficiency as well as make it difficult to agitate/stir the mash.

Cheers,
PP
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Post #23 made 8 years ago
Hi I am thinking about a bag for my brewpot and have issues with a thermometer probe
yetiboy,
I have the same problem. I was a "Old fashioned" 3V type brewer. I thought I needed a probe. I really haven't had too much trouble with it. As long as I remember to use the SS spoon to push the bag away from the probe all is well. I did once did catch the prob and bent it without ripping the bag. The prob still works but I really don't use it much. I do like to compare the "Below" temperature from the mash temperature quite a difference. That is why I draw off the bottom water and dump it on my mash to even it out some. Cheers!
Last edited by BobBrews on 20 Mar 2011, 20:35, edited 5 times in total.
tap 1 Raspberry wine
tap 2 Bourbon Barrel Porter
tap 3 Czech Pilsner
tap 4 Triple IPA 11% ABV

Pipeline: Mulled Cider 10% ABV

http://cheesestradamus.com/ Brewers challenge!
    • SVA Brewer With Over 100 Brews From United States of America

Post #24 made 8 years ago
dick wrote:I wrote in the post that PP gave a link to that I work for a textile manufacturer so now I get to be the go to guy for bag material questions. No probs PP - I will help if I can. I should mention that the textiles I deal with are not for clothing or domestic applications like curtains or shadecloth, but they do act as a filter which is a bit like what we are doing with BIAB.

The most common questions I see about the material are what kind of material, what is the melting temperature and how sheer should the fabric be.

<snip>

Anyone have questions or anything to add?

Cheers
Dick
I have a question to add. A fellow in my brewing group expressed concern/speculation about breaking down of the material in a hot, low pH environment. He was wondering:

(a) to what degree the amines leached out of the material
(b) what they might do (I presume by this he meant to the drinker, accumulation in the body that sort of thing, do they affect or even make through the fermentation phase)

Can someone help me with this information?
Last edited by CanBrew on 20 Mar 2011, 22:35, edited 5 times in total.

Post #25 made 8 years ago
CanBrew wrote:I have a question to add. A fellow in my brewing group expressed concern/speculation about breaking down of the material in a hot, low pH environment. He was wondering:

(a) to what degree the amines leached out of the material
(b) what they might do (I presume by this he meant to the drinker, accumulation in the body that sort of thing, do they affect or even make through the fermentation phase)

Can someone help me with this information?
Although not a specific answer this link is for a manufacturer of Polyester cooking bags which states they can be used up to 400f in conventional ovens

http://www.mqplastics.com/polyester-shr" onclick="window.open(this.href);return false; ... g-bags.php
Last edited by Yeasty on 21 Mar 2011, 07:32, edited 5 times in total.
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