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BIAB Polyester Voile Strength Test

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wilserbrewer

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Out of curiosity, I conducted a simple polyester voile strength test.

The bag, poly voile machine triple stitched w/ tight zig-zag type stitch...

http://biabbags.webs.com/




The weight, 67 lbs of dumbbells, 2 - 20's, 1 - 15, and 2 - 6's...67 lbs total



The strap tied off to the top of the bag, this is an inexpensive HF lashing strap, it works quite well to suspend the bag from a ceiling hook. I prefer this method as it spreads the load over the entire bag, as opposed to stitched handles or attachment points on the bag.

A short length of cord or rope can also be easily wrapped and tied around the top of the bag for lifting and will cinch the bag very well for even heavy duty lifting.


The test, bag took the weight w/ no issues...none whatsoever!



I have done BIAB grain bills close to 40 lbs, and have always surmised the poly voile could handle more weight, I would also imagine the irregular shaped dumbbells put much more stress on a bag than the even loading of a mash. Also interesting to note that I believe a grain bill of x pounds, weighs less than x after conversion and water absorption, so a 20 lb grain bill weighs less than 20 lbs after being lifted out of the kettle.

Myths busted:

1. BIAB is not viable for larger batch brewing.
2. The use of a strainer basket is needed to support the bag.
3. Handles are needed on a BIAB bag for large grain bills.

Thanks for watching this experiment...cheers!
 

mb82

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Very cool. Well that says weight is no an issue currently for me. Now to double/triple stitch my bag.
 

signpost

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That's pretty cool.

However, I find it hard to believe that the sugars removed from the grain during the mash weighs more than the water the grain absorbs. It has seemed pretty obvious in my few BIAB batches that the grains weighed more after absorbing water than they did before I dumped them in the kettle.

I might be wrong, but I'd have to see some proof from a scientific test of some sort before believing it. Of course, there is a big difference between the weight as it is lifted from the kettle and after it has drained sufficiently. So, any test of this question would have to be specific about the amount of time for draining before weighing the spent grains.
 

TacoBrew

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It might weigh less once the bag drains, but when you pull it out of the kettle, it is definitely heavier. That being said, I've done up to 36lbs in my BIAB bag and had zero problems or any fear of it ripping. Even after increasing the stress by twisting the bag 15-20 times to squeeze out the liquid, it held strong.
 

aubiecat

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The bags I have made with poly voile will take some serious abuse. I still use my steamer basket because it's easier for me to drain the bag after mashing.
I also use my BIAB bag in my 10 gallon Igloo mash tun.

 

johns

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Take 10 pounds of grain at an absorption rate of water at .06. That would equal 0.6 gallons of water. Now take the weight of water to be 8.35 pounds for a gallon. So it would be 0.60 gallons of water * the weight of a gallon of water 8.35 is 5.01. A 40 lb grain bill would add about 20 pounds of wieght.
 
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wilserbrewer

wilserbrewer

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Take 10 pounds of grain at an absorption rate of water at .06. That would equal 0.6 gallons of water. Now take the weight of water to be 8.35 pounds for a gallon. So it would be 0.60 gallons of water * the weight of a gallon of water 8.35 is 5.01. A 40 lb grain bill would add about 20 pounds of wieght.
This is true above, if you have not extracted ANY sugars from the grain???::confused: That doesn't come free;)

Boy, you conduct a little science experiment around here and all the geeks come out of the closet...hahaha
 

hustlebird

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So I just wanted to chime in, because i figured the weight of the sugars would actually be insignificant, but after looking at the numbers, its pretty substantial. At least if I understand things correctly.

2 row is roughly 1.038 points per gallon per pound, table sugar is 1.046 per gallon per pound, so that means 2 row is approx 83% sugar right? Thats really interesting to me, because the grain probably is significantly lighter after conversion then before. I'll have to bust out my scale and to look and measure, including tracking of grain absorption of water, next time I brew. Fun stuff!

Edit: I am scatterbrained, clarified some wording...
 
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wilserbrewer

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DING DING - ROUND TWO

Well for kicks and curiosity, we stepped it up and conducted round two.

The weight...120 lbs...



The ratchet strap...



The lift...



No issues at all, not even a stretched seam. This is the upper limit, the bag is nearly full of steel at this point...haha. Cheers and hope you enjoyed this silly experiment...
 

mb82

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No experiment is silly. This proves that you can have 120lbs of water+grain in the bag and lift it without issues. That is overkill for 99% of the BIAB people here but it proves that the Voile bags when built correctly can handle anything we throw at them, we will fail before they do.
 

whiskeyjack

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I'm thinking of ordering one of these. Are they food grade safe at mashing temps and where do I order them ?
 

alien

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That looks like hard work. The biggest BIAB I did was 10 kg of grain.
 

alien

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Did you haul the bag out? I found it easier to tie the bag in place and drop the pot down.
 

dazed

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I pulled it up enough to clear the pot then put the lid on.
I then put a bucket on top of that, and lowered it in the bucket and took it away.
 

johns

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Dazed, Just courious, how much grain is that and would all that grain fit into a large Igglo cooler? Add a few gallons of water and do something like a junk sparge if you wanted to increase the effeciency.

On another thought I also wonder at what point would a voile bag break. I mean if you were to delibertly break a voile bag, how much wieght would it take to do that. At what point would the material break. With a bag that large (pictured), I think it would be possible, to add say 150 lbs of dead wieght. The bag would be lost, but it would be interesting to know.
 
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wilserbrewer

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On another thought I also wonder at what point would a voile bag break. I mean if you were to delibertly break a voile bag, how much wieght would it take to do that. At what point would the material break. With a bag that large (pictured), I think it would be possible, to add say 150 lbs of dead wieght. The bag would be lost, but it would be interesting to know.
I packed 120 lbs of steel into a bag, and the crowd cries for more :confused::confused:, sorry I aint goin there...please realize that 150 lbs of grain would require an enormous bag, and a bigger bag would only be stronger.

If anyone cares to $fund$ my research...I'll gladly up the stakes to 300 lbs. I will have to convince the ex to get in the bag though:D
 

TerraNova

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This is quite impressive.

A question not related to the strength of the bag, that seems to have been proven, why the teardrop shape of the bag as opposed to a square? I would think a square shape would maximize the cloth material and reduce waste/cost.

Is there an advantage to the mechanics of that shape?
 

alien

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IMO the best shape is cylindrical with a taper so it's narrower at the bottom.

Pillow-case shaped bags get very wide in the bottom corners.
 
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wilserbrewer

wilserbrewer

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Some is personal preference of course, in my experience, the teardrop shape works very well. The bag when properly sized will easily fully conform to the interior shape of the pot, yet when lifted out of the kettle will shape nicely and neatly direct a single stream of wort to drain back into the kettle.

IMO, the cylindrical bags are overly complicated, and place multiple seams and potential points of failure at the bottom of the bag, and also do not shape as nicely when removed from the kettle. In theory they seem attractive, yet in practice I feel the tear drop shape superior. Rectangular shaped bags will actually form into two large lumps and drip multiple streams of wort back into and also outside the kettle rim, and be wider than the kettle and can be messy.
 

TerraNova

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...yet when lifted out of the kettle will shape nicely and direct a single stream of wort to drip back into the kettle.

Rectangular shaped bags will actually form into two large lumps and drip multiple streams of wort back into the kettle, and be wider than the kettle.
That make sense. I just may have to get one of these.
 

dazed

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My bag has a circle on the bottom (Cylindrical matching my pot)....
I'm guessing its just easier to sew up in tear drop style since you only have 1 continuous seam, and
would also be better than a tea-bagged pillow case style leaking over the edges.
 

signpost

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My bag has a circle on the bottom (Cylindrical matching my pot)....
I'm guessing its just easier to sew up in tear drop style since you only have 1 continuous seam, and
would also be better than a tea-bagged pillow case style leaking over the edges.
I made my bag with a circle on the bottom and cylindrical shape on top of that, as well. I need to finish up the top part by sewing on a drawstring. I was in a hurry when I made it and left that step off, because the batch I was about to brew was just a partial mash and only had 3.5 lbs. of grain. But I'm going to be doing a Kolsch with 9 lbs. of pils malt this weekend. The drawstring will make things easier, for sure.
 

ja09

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These bags are looking pretty attractive for my setup! What do you think about also using them for lining the kettle and boiling the entire time? Any chance they can melt or produce off flavors? I'll need a way to filter trub a little better for big ipas.
 

brewmcq

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DING DING - ROUND TWO

Well for kicks and curiosity, we stepped it up and conducted round two.

The weight...120 lbs...
Mr. Savage and Mr. Hyneman approve.

The only thing that would make it better is C4. And some sort of robotic rocket. With tentacles. And a flamethrower.
 

Seven

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Nice experiment wilserbrewer. Another thought is to try it with the bag wet and at mash out temp of 170F.
 

dazed

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What do you think about also using them for lining the kettle and boiling the entire time? Any chance they can melt or produce off flavors?
I would not boil in them. After all its some kind of plastic, if its polyester ...
 

ja09

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I would not boil in them. After all its some kind of plastic, if its polyester ...
If it's nylon, the melting point should be over 400°F. Not sure what other materials are used though. I've read on here people melting part of their BIAB or paint strainer bag when boiling, but I don't see how that could happen with nylon. Hopefully the OP can chime in.
 

ja09

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Duh, says Polyester right in the title. I'm an idiot :cross:

I guess the question is what type of Polyester is it exactly?..and because it states "Polyester voile", does this mean it's blended with cotton?
 

brewmcq

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Polyester has a melting point of roughly 480F (multiple sources, google it).

Water can only reach 212F, no matter how hard you boil it.

Therefore, the absolute hottest the bag can get is 212F.

It's the same reason you can boil water in a paper cup. The temperature of the water keeps the cup cooler than it's ignition point by way of conduction.
 

ja09

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Polyester has a melting point of roughly 480F (multiple sources, google it).
Thanks. I'm aware of google ;) Do you boil with this particular bag?

These bags are advertised as 'Polyester Voile', which in my research, is different than 100% polyester. If you dig a little deeper you'll notice multiple sources reference something along the lines of "blending Polyethylene with other materials such as cotton significantly reduce the material's melting point"


I know people boil with their BIAB bags, I was just wondering about lining my kettle with this particular bag/material, especially with an immersion chiller sitting on top of it.
 

brewmcq

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It makes so sense in boiling with the bag still in place. So no, I don't boil my bag. The hottest it gets is my strike temp, which is usually around 167F.

The voile panels I get at Walmart to make my bags say "100% Polyester". Not that I trust WalMart any further than I can throw them...
 

ja09

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It makes so sense in boiling with the bag still in place. So no, I don't boil my bag.
I'm guessing you meant 'no sense'. Why doesn't it make sense? Ever heard of a hop spider? This would just be a large version of one that I can also mash with. Could be an awesome piece of equipment if it worked for both :mug:
 

brewmcq

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Yeah.. "no sense".. But I'll rephrase...

It makes no sense to boil the BIG (grain) bag.

I have two smaller bags I use for hops, and yes, I boil those, and yes, everything is fine... no melting. No off-flavors. No catastrophic doomsday.

:)
 

ja09

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It makes no sense to boil the BIG (grain) bag.
So you don't have any idea if these will hold up in the boil. Ok, got it. There are plenty of people on this forum that have stated their BIAB bag melted in the BK.

My immersion chiller makes it tough to use a normal hop spider/smaller bags, so it makes plenty of sense, plus this is just easier. I was asking this question in regards to my setup, not yours :)
 
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