BIAB Polyester Voile Strength Test

[Seven]

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

 

[dazed]

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]

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]

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]

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]

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]

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]

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

 

[brewmcq]

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]

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

 

[brewmcq]

If you'd like, I'll toss my grain bag in my kettle when I get home on Friday and let it boil for a couple hours...

I do need to run autotune on my PID again... and make better calculations on my boil-off rate... so I'll see if I can melt my bag while I'm at it.

Keep your bag off the element and it will never melt.

 

[ja09]

That would be great. I should send you some beer for your efforts!

 

[brewmcq]

 

[wilserbrewer]

Ok...thanks guys and gals!

Sorry, but I have no desire or the ability to test the voile strength at mash out temps...my gut tells me it is plenty strong!!!

Sorry again, but I have no desire to use a hop bag as large as the kettle. I'd be happy to make one if someone desires.

Boiling does not seem to affect the polyester voile.

Polyester bags can of course burn on the bottom of a direct fired kettle if packed with a mash and not stirred, I assume there is not enough flow to keep the temps in check, but this is true of any mash that is direct fired and the grain will scorch, no???

Low heat and stirring will typically not harm the bag if heat is applied. If one applies heat and leaves a compacted mash on the bottom of the kettle, it will scorch either with or without a bag. When heating any mash, stirring is needed to avoid scorching the grain and bag if present.

Thanks!
wilser

 

[Seven]

Aw come on... plenty of people are mashing their dumbbells all over the country right now... you're missing out!

Heat does make it more stretchy. Just sayin'.

 

[HopsNOps]

You had me a 120 lbs - I'm in - thanks for the extra testing - been brewing for years and looking to make the switch to BIAB but was very, very leary of the bags - nice work and see you through PayPal!!!

 

[typebrad]

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...

Dude, that's awesome. My next IIPA has a 120lb. Grain bill!

 

[toddsyn]

LOL I have been looking at trying this and researching. I was impressed with a few different products but when I read the 300 lbs ex comment you sold me. I will be looking forward to doing business with you soon.

 

[CowboyNate]

I've used BIAB for a while now ( more than 20 batches with the same keggle sized bag) and know the weight capability is good.
For that matter, I know the squeezing capability is good (cuz I'm cheap like that), but what is the max pressure the seams on a bag can handle? I assume the seams are the weak point for this one.

If one had a bag one was willing to sacrifice, wring out the grains post-mash as you normally would and weigh the bag/damp grain. Figure out how much water remains in the grains from that.
Once the boil is going and you're now bored, lay out a tarp under your wringing setup and give it another go (until failure). Trick will be how to collect the liquids so you know how much more you've extracted without adding grain back in when the bag fails..... Totally an overcomable obstacle.
Bonus is to compare a) how dry you normally get the grains, and b) how dry you *could* get them if you went to extremes.

This could also be a bit of a selling point for the bags: I know a lot of people are afraid of wringing the grains, but I want data to prove out why I shouldn't wring harder before I can buy into it. (My dad's a professor and statistician; I grew up to the phrase, "Show me the data," whenever I had some statement to make.)

 

[doug293cz]

I've used BIAB for a while now ( more than 20 batches with the same keggle sized bag) and know the weight capability is good.
For that matter, I know the squeezing capability is good (cuz I'm cheap like that), but what is the max pressure the seams on a bag can handle? I assume the seams are the weak point for this one.

If one had a bag one was willing to sacrifice, wring out the grains post-mash as you normally would and weigh the bag/damp grain. Figure out how much water remains in the grains from that.
Once the boil is going and you're now bored, lay out a tarp under your wringing setup and give it another go (until failure). Trick will be how to collect the liquids so you know how much more you've extracted without adding grain back in when the bag fails..... Totally an overcomable obstacle.
Bonus is to compare a) how dry you normally get the grains, and b) how dry you *could* get them if you went to extremes.

This could also be a bit of a selling point for the bags: I know a lot of people are afraid of wringing the grains, but I want data to prove out why I shouldn't wring harder before I can buy into it. (My dad's a professor and statistician; I grew up to the phrase, "Show me the data," whenever I had some statement to make.)

Sometimes you just have to collect your own data.

I think it would be quite difficult to stress a bag to fail without resorting to unusual ways to concentrate stress to very localized regions of the bag.

Brew on

 

[CowboyNate]

Also feeling kinda silly; I didn't mean to try resurrecting and old thread. Ah well.

 

[wilserbrewer]

No problem Nate, I just don't understand the fascination with trying to capture every last drop of wort....I find it much easier to just let gravity drain the bag, then I happily pass on the last little bit of wort to the deer in the back feeding at the spent mash pile. I figure less than 25 cents, and you'd be hard "pressed" to capture half that, let alone wreck your bag in the process.

Cheers!
wilser

 

[CowboyNate]

No problem Nate, I just don't understand the fascination with trying to capture every last drop of wort....I find it much easier to just let gravity drain the bag, then I happily pass on the last little bit of wort to the deer in the back feeding at the spent mash pile. I figure less than 25 cents, and you'd be hard "pressed" to capture half that, let alone wreck your bag in the process.

Cheers!
wilser

Understood re: fascination with capturing every last drop.

However, sometimes it's less about getting it out than knowing how close one is to disaster. Also, unfortunately, it's extremely tough to gauge in normal circumstances. Just when exactly have you reached 50PSI? 75? 100? 200?
It'd be impossible unless you put a guage in with your mash, and, well, yeah.

I too take after a "it's just beer" approach; I don't make sure everything it mathematically correct and then fuss when it's off of by some digit that's scientifically impossible to measure with the equipment available.
I would like to know just when I'm getting close to deep doo doo cuz I just blew out a seam in the side of my bag.

Heck: each their own way of doing things.
Nate

 

[dazed]

I would like to know just when I'm getting close to deep doo doo cuz I just blew out a seam in the side of my bag.

Heck: each their own way of doing things.
Nate

If you continue down this path....I suggest you purchase an extra bag.

Just squeeze it the same every time for your consistency... if your gonna squeeze.

I believe your over complicating the whole BIAB approach.

RDWHAHB

 

[jmpreiks]

I would like to know just when I'm getting close to deep doo doo cuz I just blew out a seam in the side of my bag.

Unless your mechanically squeezing it like by ratcheting your bag through a set of steel rollers, you are never going to stress the seams like he showed by adding 120lbs to the bag...

Assuming you are using bags of his same quality, squeezing with your hands just won't break it. Even if you are this guy:

Edit: I guess you could probably break it by twisting it a million times into a tight ball, but again.... just don't go crazy on it.

 

[ja09]

Cheers!
wilser

Question for you wilserbrewer. I would like a bag for my round 10g cooler MLT, but I also have a wide 15g megapot (old version) that it would come in handy for the times I partial mash, which isn't very often.

Do you think one bag could work well for both, or would the extra width be too sloppy for the cooler?

 

[wilserbrewer]

ja09,

The beverage cooler is tall and slender, while the early mega pots are short and wide. While I have no problem making a bag that is usable in both, perhaps you would be better served to size to the cooler you use most frequently, and make the bag "work" for the occasional PM in the kettle. The taller slender bag would function for occasional PM in the mega pot, it just wouldn't be best fit.
PM sent.

 

[Todd820]

Personally, I use a bag from bagbrewer.com and really like it. The wilser bags look nice, but I like the straps on mine quite a bit and it has been a very durable bag for me. Guessing I have 35+ brews in with this bag. Probably due for a new one as I am noticing some wear and a couple of holes starting but I treat this thing like crap. Never really thought I would get that many batches out of it.

I do like the looks of that pulley on the wilser bag site too - sure beats my sorry ass contraption.

 

[doug293cz]

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.

I realize this is an old thread, but I didn't have the spreadsheet to answer this question when it was first brought up.

The weight of the bag after draining will depend on the absorption rate, which will depend on how long the bag is drained, and how aggressively it is squeezed.

I did a simulation with a 15 lb grain bill, and absorption rates of 0.06 gal/lb and 0.12 gal/lb. The first is typical for a moderately aggressive bag squeeze, and the second is typical for a short drain with no squeeze. The results are:

0.06 gal/lb ending mash weight (not including bag): 19 lb​

0.12 gal/lb ending mash weight (not including bag): 27 lb​

​

So, yes the bag with spent grain and absorbed wort, will weigh more than the original grain bill in most cases. The spent grain, without the absorbed wort is ~4 lb.

Brew on