I like this idea. I'll get my mother in law to sit on it --- probably get about 110% efficiency.
To Squeeze and How Much To Squeeze
- Thread starter Bigarcherynut
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I like this idea. I'll get my mother in law to sit on it --- probably get about 110% efficiency.
wilserbrewer
BIAB Expert Tailor
All this love for squeezing and donning heat resistant mitts to squeeze harder, calloused hands and building boards and clamps to squeeze the sack, I just don't see the pleasure or reward at all!
The force of gravity at my home must be extraordinary, I find just patiently letting the bag drain over the kettle for 20-30 minutes yields all but a few ounces. So much so that I have a hunch that a lengthy and thorough gravity drain yields more than you's guys, "squeeze it like it owes you money" nonsense.
Meh...whatever pleases you, carry on.
Likely only about $0.20 worth of grain anyways, better to look between the couch cushions for a quarter or maybe two would be a better use of effort.
Cheers
The force of gravity at my home must be extraordinary, I find just patiently letting the bag drain over the kettle for 20-30 minutes yields all but a few ounces. So much so that I have a hunch that a lengthy and thorough gravity drain yields more than you's guys, "squeeze it like it owes you money" nonsense.
Meh...whatever pleases you, carry on.
Likely only about $0.20 worth of grain anyways, better to look between the couch cushions for a quarter or maybe two would be a better use of effort.
Cheers
I tried this based on your previous experiences, and I actually had about a 10% drop in brewhouse efficiency even though I ended up with the same volume measurements that you did.
I suspect that my issue is that the bag cools substantially over the course of 30 minutes and thus the concentration of sugars in the gravity drained wort is lower than in the squeezed bag wort.
I'm also combating a LHBS crusher that's set to a tradition mash/lauter crush, So I'm buying my own shortly to eliminate that variable as well and that will hopefully overcome the issue I have with hanging.
Stovetop BIAB = No way to hang the bag over the kettle while starting the boil. I guess some stoves don't have an overhead exhaust fan, but most do.
wilserbrewer
BIAB Expert Tailor
Huh? Wort is wort, I doubt hot squeezing gets more sugar laden wort than cooler slower draining, unless of course your squeezing in the middle of Jack's magical bean field 
Guessing your mystery variable is crush.
Seeing as how you retrieved a comparable volume, that supports my thinking.
Yes, Fatdragon I do realize that small batch and stovetop is not conducive to hanging the bag over the kettle, maybe try tossing it in a colander over a bucket for a 1/2 hour while trying not to look at it all the while resisting the urge to get in there with gloved ham hands and squeeze away. Lol thx
Jmo guys, squeezing is work, gravity is free, maybe I'm just lazy.
My rule is, unless it is gonna make better beer, just don't do it.
Ok sorry to interrupt this broadcast, back to the squeezing.
Guessing your mystery variable is crush.
Seeing as how you retrieved a comparable volume, that supports my thinking.
Yes, Fatdragon I do realize that small batch and stovetop is not conducive to hanging the bag over the kettle, maybe try tossing it in a colander over a bucket for a 1/2 hour while trying not to look at it all the while resisting the urge to get in there with gloved ham hands and squeeze away. Lol thx
Jmo guys, squeezing is work, gravity is free, maybe I'm just lazy.
My rule is, unless it is gonna make better beer, just don't do it.
Ok sorry to interrupt this broadcast, back to the squeezing.
Ike
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Huh? Wort is wort, I doubt hot squeezing gets more sugar laden wort than cooler slower draining, unless of course your squeezing in the middle of Jack's magical bean field
Guessing your mystery variable is crush.
Seeing as how you retrieved a comparable volume, that supports my thinking.
Yes, Fatdragon I do realize that small batch and stovetop is not conducive to hanging the bag over the kettle, maybe try tossing it in a colander over a bucket for a 1/2 hour while trying not to look at it all the while resisting the urge to get in there with gloved ham hands and squeeze away. Lol thx
Jmo guys, squeezing is work, gravity is free, maybe I'm just lazy.
My rule is, unless it is gonna make better beer, just don't do it.
Ok sorry to interrupt this broadcast, back to the squeezing.
The bag goes in a perforated bucket inside another bucket and gets a batch sparge and usually 15-20 minutes to drain. At that point, it's cool enough to squeeze and I can get another 2-3 liters of wort with about a minute and a half of kneading against the bottom and walls of the bucket. Squeezing them fairly dry also makes the grains a lot easier to dispose of as I have to take them down from my 24th floor apartment in leaky Chinese garbage bags. My process would probably be different if I had found an adequate colander early in my adventures, but everything I've seen has been too small or too flimsy for the job, and it really takes a bucket to contain the grains from the occasional high gravity batch anyway, so I'm happy with my process.
Huh? Wort is wort, I doubt hot squeezing gets more sugar laden wort than cooler slower draining, unless of course your squeezing in the middle of Jack's magical bean field
Guessing your mystery variable is crush.
Lol no magical beans here. We have plenty of lentils here though.
I wasn't terribly clear, my crush was consistent (just on the coarse side for BIAB) but my efficiency dropped when hanging vs not hanging.
I suspect temperature because the solubility of sugar in water increases with temperature and the viscosity of the wort decreases. I could be totally wrong, and at least part of the difference could actually be the bag. I'm not using one of your bags, so my clearly inferior bag choice may be hindering may lauter efficiency
@doug293cz has some interesting graphs concerning viscosity and temperature that I always forget to copy whenever he posts them. Maybe he'll do is a favor and post them yet again?
Also, he had some info on the solubility of sugar in water versus temperature as well. Basically, the concentration we're working with is no where near the saturation limit of the water and temperature has negligible impact on the solubility.
Lol no magical beans here. We have plenty of lentils here though.
I wasn't terribly clear, my crush was consistent (just on the coarse side for BIAB) but my efficiency dropped when hanging vs not hanging.
I suspect temperature because the solubility of sugar in water increases with temperature and the viscosity of the wort decreases. I could be totally wrong, and at least part of the difference could actually be the bag. I'm not using one of your bags, so my clearly inferior bag choice may be hindering may lauter efficiency
Your reasoning has major flaws and defies the laws of physics. Squeezing or draining to the same volume all else being equal will have zero difference in the sugars in the kettle all else being equal. You are 100% barking up the wrong tree in your reasoning here.
The solubility limit of sugar in water is far far far beyond the reaches of any kind of gravity resulting in brewing. All sugars present are in solution. The SG of the wort in the kettle and the wort in the hanging/squeezed bag are identical.
Think syrup or LME. All the sugars are in solution.
Draining or squeezing makes no difference to mash efficiency assuming equal volumes, grain-bill, crush etc. All other factors need to be identical. Clearly they were not hence the difference in the numbers.
Thanks got that already, see above.
Yeah. Just posted before reading the rest of the thread. Sorry 'bout that, didn't mean to pound the point home more than it had already been pounded.
No worries, happens to me all the time.
So now that we've established that I'm dead wrong about my hypothesis, I have some questions.
Do you assume 100% lautering efficiency for all BIAB methods?
If so, how do you account for people who boost efficiency with a dunk or pour-over sparge? It seems to me like that is effectively flushing more sugars from the grains by the sparge water displacing any sugar laden water in the wet grain. But, as we are all squeezing or hanging, it shouldn't really matter whether you dunk sparge or not since the grain absorption of BIAB is minimal (I usually see about .05-.08 L/lb of grain)
If sparging methods do not improve efficiency of BIAB, then really the only things I should worry about are crush, mash length, and pH?
Dialing in my efficiency to a consistent number on my system is something I'm struggling with currently, so any advice is appreciated.
Sparging does improve efficiency. For no-sparge and batch sparge, it is possible to calculate the lauter efficiency. The chart below compares no-sparge to equal runnings volume batch sparge for different grain bill weights for several different grain absorption rates. 6.7 gal pre-boil volume is assumed for all cases, as is zero MLT dead volume (standard for BIAB.)
Brew on
@madking
No not assuming 100%lauter efficiency with any method. That would be totally wrong and a physical impossibility.
BIAB. The fundamentals are identical wrt mashing sparging.
Strive for very close to 100% conversion efficiency and your mash efficiency will be largely dictated by lauter ing efficiency. Some sugars will always remain in the mash regardless of method.
No not assuming 100%lauter efficiency with any method. That would be totally wrong and a physical impossibility.
BIAB. The fundamentals are identical wrt mashing sparging.
Strive for very close to 100% conversion efficiency and your mash efficiency will be largely dictated by lauter ing efficiency. Some sugars will always remain in the mash regardless of method.
Sparging does improve efficiency. For no-sparge and batch sparge, it is possible to calculate the lauter efficiency. The chart below compares no-sparge to equal runnings volume batch sparge for different grain bill weights for several different grain absorption rates. 6.7 gal pre-boil volume is assumed for all cases, as is zero MLT dead volume (standard for BIAB.)
View attachment 333399
Brew on
awesome graph doug, thank you, that cleared up a lot of my confusion.
Now I'm curious as to the actual physical mechanism behind why sparging increases efficiency for a given grain absorption and grain bill. Effectively, where is the sugar hiding that requires a sparge instead of just water removal to get it out, and what physical form is it in?
It cannot be a solute otherwise it would drain out with the wort during a no-sparge. I can only infer that it must be still contained within the grain kernals or on their surfaces as a solid or semi-solid. If that is the case, then it would seem that the temperature of the sparge water would affect the rate of dissolution of these residual sugars, which Brukaiser's experiment shows is false.
These are mostly just curiosity questions, since the actual practice of HOW to get the sugars out is well understood.
I will be making a Vienna lager this weekend and I'll do a dunk sparge and long drain and see how it goes since I still don't have positive control over my crush.
wilserbrewer
BIAB Expert Tailor
Sparging increases efficiency because it further dilutes the sugars that remain in the wort that is absorbed by the grain. In a no sparge, the sugar content of the absorbed wort will be the same as the collected wort, sparging will reduce this and improve efficiency. This becomes more significant as gravity increases.
The sugars that remain are in solution in the wort that is absorbed by the grain, and to retrieve all the liquid would be 100% lauter efficiency, there is no solid sugar.
Simply put, with a sparge you are rinsing more, not dissolving more.
The sugars that remain are in solution in the wort that is absorbed by the grain, and to retrieve all the liquid would be 100% lauter efficiency, there is no solid sugar.
Simply put, with a sparge you are rinsing more, not dissolving more.
The sugar is all dissolved in water, since it is created from starch that is either dissolved or gelatinized. Solid sugar never exists in the mash.
The grain bed is like a sponge. If you have a sponge in a bowl of water, and pour off the water, there is still a significant amount of water in the sponge. If you squeeze the sponge, you get some of the residual water out.
Now let's put the sponge in a bowl of sugar water. After draining off the liquid, the sponge still contains some sugar water, and thus some sugar. If you add more water to the bowl, and squeeze the sponge a lot, you can equalize the concentration of sugar between what was in the sponge and the added water. Now when you pour the water out of the bowl, the sponge contains about the same amount of liquid that it did the first time you drained the bowl, but a lot less sugar.
Now let's do the same thought experiment, but without the sponge, and this time we'll throw in some numbers to make it quantitative. Let's say we have a container with 10 gal of liquid that is 10% sugar. If we pour off 9 gal, we still have 1 gal of liquid in the container that is 10% sugar.
If instead of starting with 10 gal of 10% solution, we start with 5 gal of 20% solution, and pour off 4 gal, we have 1 gal of 20% solution left in the container. If we add 5 gal of water to the container and mix well, we have 6 gal of 3.33% sugar. Now we pour off 5 gal of the 6 gal, leaving 1 gal of 3.33% sugar solution in the container.
The second process leaves only 1/3 as much sugar in the container, thus more sugar is in the drained solution. We had the same total volume of solution, and the same volume of total draining, but got more of the original sugar in the drainings than the one step process. That's how sparging works.
The above is a little over simplified since it ignores the details about specific gravity, but it demonstrates what is going on with sparging. The simulations I used to make the chart take into account all of the gory details.
Brew on
The sugar is all dissolved in water, since it is created from starch that is either dissolved or gelatinized. Solid sugar never exists in the mash.
The grain bed is like a sponge. If you have a sponge in a bowl of water, and pour off the water, there is still a significant amount of water in the sponge. If you squeeze the sponge, you get some of the residual water out.
Now let's put the sponge in a bowl of sugar water. After draining off the liquid, the sponge still contains some sugar water, and thus some sugar. If you add more water to the bowl, and squeeze the sponge a lot, you can equalize the concentration of sugar between what was in the sponge and the added water. Now when you pour the water out of the bowl, the sponge contains about the same amount of liquid that it did the first time you drained the bowl, but a lot less sugar.
Now let's do the same thought experiment, but without the sponge, and this time we'll throw in some numbers to make it quantitative. Let's say we have a container with 10 gal of liquid that is 10% sugar. If we pour off 9 gal, we still have 1 gal of liquid in the container that is 10% sugar.
If instead of starting with 10 gal of 10% solution, we start with 5 gal of 20% solution, and pour off 4 gal, we have 1 gal of 20% solution left in the container. If we add 5 gal of water to the container and mix well, we have 6 gal of 3.33% sugar. Now we pour off 5 gal of the 6 gal, leaving 1 gal of 3.33% sugar solution in the container.
The second process leaves only 1/3 as much sugar in the container, thus more sugar is in the drained solution. We had the same total volume of solution, and the same volume of total draining, but got more of the original sugar in the drainings than the one step process. That's how sparging works.
The above is a little over simplified since it ignores the details about specific gravity, but it demonstrates what is going on with sparging. The simulations I used to make the chart take into account all of the gory details.
Brew on
Awesome explanation and metaphor, thanks for taking the time to type all that up. I understand why it works now, so I can start making improvements to my system.
I wonder (and maybe you've already examined this) how much crush size is affecting the water retention in the grain and therefore increasing the need for sparging vs how much the crush affects conversation efficiency and reduces actual total sugars in solution.
Since traditional mashing and lautering use a larger crush and can maintain higher efficiencies, I would initially suspect the former.
Glad it was helpful.
I have not looked at crush size vs. absorption rate, and am not aware of anyone who has. For traditional MLT's the limited range of useful crush sizes probably limits this effect. For BIAB, the absorption rate is so dependent on aggressiveness of squeezing, that any general rule would not apply most of the time.
BIAB with aggressive squeezing and a sparge can beat traditional 3 vessel plus batch sparge due primarily to lower grain absorption, and secondarily due to better conversion efficiency from the finer grind.
Brew on
I hang it and almost always hit my volume and gravity # keep it simple that's what BIAB is all about....seems like to many are making BIAB more complicated in the last couple years to me...one vessel & a bag for me...
That's the beauty of homebrewing. There are lots of ways to do it, from simple to complex, and they all work! Just about anyone can find a process that meets their needs for simplicity, elegance, control, gadgetry, complexity... whatever floats their boat. Eventually most brewers arrive at the process that's right for them.
Brew on
I always squeeze to "hit my numbers". But reading through this, the only numbers I need to concern myself with is volume. If the gravity in the wort is the same as the gravity in the wet grain then just let it hang until volume is reached.
I would squeeze till it hurt THEN take my gravity reading. I should just take gravity then wait for the volume to be reached. If my calculations are correct in Beersmith then it should all work out.
I would squeeze till it hurt THEN take my gravity reading. I should just take gravity then wait for the volume to be reached. If my calculations are correct in Beersmith then it should all work out.
OP
OP
Bigarcherynut
Well-Known Member
That's the beauty of homebrewing. There are lots of ways to do it, from simple to complex, and they all work! Just about anyone can find a process that meets their needs for simplicity, elegance, control, gadgetry, complexity... whatever floats their boat. Eventually most brewers arrive at the process that's right for them.
Brew on
Thanks for your input on this. Never thought my thread would get this many responses and opinions.
Being just a beginner at BIAB I was trying to get my mash efficience above my first batch which was 88%. Now I see there is more to it. After looking at my third batch numbers it appears all I got was a lower grain absorption number .06. I used a finer crush, a double run at .03 versus .04 for my first batch and I did a 90 minute mash compared to a 60 minute. My gravity readings didn't improve much at all. They went from 1.040 at the 60 minute mark to 1.047 at 90 minutes. My volume after squeezing with my board setup went from 7.75 gallons to 8.35 gallons. Note I was over on my initial water amount because I did not have the proper boil off rate. The boards made it easier and got more out of the grains.
I'm thinking of now trying some type of sparger to see what it will do to my numbers which from what I read should increase. Now the million dollar question. What would be my best option.
A dunk type or what I would think would be easier would be to lift the bag out of the wort, open it up and poor the sparge water over the grain. Now the other part of the question, how much water?
Thanks all.
Well the "how much water" I can answer
Desired preboil volume + expected grain absorption - sparge water = mash water
The actual amount of sparge water is up to you, just make sure you have enough mash water to be over ~1.5qt/lb of grain (thinner is better)
Desired preboil volume + expected grain absorption - sparge water = mash water
The actual amount of sparge water is up to you, just make sure you have enough mash water to be over ~1.5qt/lb of grain (thinner is better)
I've done both. Your preference will probably depend on your set up. If you've got a way to hoist the bag, open it and pour sparge water over, then that's the way I'd go. I found there was a lot more manual labor involved with dunk sparge than this method.
Concerning how much water to use, just keep pouring water over the top until you hit your volume. Then move the bag to the side. You don't even need to know your grain absorption rate!
Don't use beersmith I use priceless cacultor it works give or take a quart...there are alotta different ways of doing things & I have tried several but when I have kettle Rollin I end up with a garage full of people and simple works best for me....I have sqeezed duncked & every other thing but the string works for me & I don't let it hang all that long to get volume...kinda like cooking it always good & never quite the same and I'm totally good with that...
OP
OP
Bigarcherynut
Well-Known Member
Thanks.
I have been using the Priceless calculator. I just enetered the amounts for my last batch and if I enter 2 gallons for sparge it will still give me the same amount for "Total Water Needed". I imagine that I need to subtract the 2 gallons from that and that would give me my starting amount and still be at 1.69 qt./lb.
Now with the starting amount being 2 gallons less, that has to affect the strike temp?? May need to adjust for that.
OP
OP
Bigarcherynut
Well-Known Member
I do have a pulley system. All I need to do is make a spreader to hold the bag open and I'm good to go. Is 168 degree the normal for sparge water? Using the Priceless calculator that's the default temp.
Thanks.
