Volume Loss from Lauter

Post #1 made 6 years ago
Hello again fellow BIAB'ers!

I've been struggling with how to maximize wort extraction from the grain bag after mashing is complete. While we claim that a stuck sparge can't happen with our beloved method, I have been reading a bit about the fluid dynamics of liquid flow through a grain bed (Appendix F of John Palmer's How to Brew book), and how it might differ with BIAB versus traditional lautering in a cooler-type mash tun.

My conjecture is that when we pull the bag out of the wort to drain, we are inadvertently compressing the grain bed from all directions, and thereby increasing the flow resistance to the liquid through the grain. By the addition of a round cake rack (or similar) to the process of removing the bag, I hope to show that the grain is not as compressed, and that more wort will drain naturally from the bag.

I've put together some diagrams of this on my blog at: http://basicbrewinginabag.blogspot.com/

I would appreciate your thoughts and feedback on my conjecture! If anyone has tried this, please let me know what you've found as a result. Apologies if this idea has been brought forward previously and I missed it on the forum. Thanks!

MMD21
MMD21

http://www.essentialbrewinginabag.com/

Post #2 made 6 years ago
Good Day MMD21, For some thought on drainig/compressing the grains take a look at http://www.biabrewer.info/viewtopic.php?f=21&t=1335 and http://www.biabrewer.info/viewtopic.php?f=21&t=586

My point is. I don't have time or desire to let the bag drain naturally, I found if the Ph is correct and the temperature is below 178F/80C, no tannins will be extracted.

So, after mashout, I compress the "crap" (A technical term) out of the bag and extract every drop of wort possible.

This may not be the way to brew, but, works fine for me!
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Post #3 made 6 years ago
joshua wrote:Good Day MMD21, For some thought on drainig/compressing the grains take a look at http://www.biabrewer.info/viewtopic.php?f=21&t=1335" onclick="window.open(this.href);return false; and http://www.biabrewer.info/viewtopic.php?f=21&t=586" onclick="window.open(this.href);return false;

My point is. I don't have time or desire to let the bag drain naturally, I found if the Ph is correct and the temperature is below 178F/80C, no tannins will be extracted.

So, after mashout, I compress the "crap" (A technical term) out of the bag and extract every drop of wort possible.

This may not be the way to brew, but, works fine for me!
True and very important! The correct PH, in this case, being anything above 5.6 in my testing, with a huge increase in tannin extraction (and increase in beer turbidity) once the PH rises above 5.9.

With any draining/squeezing process, a critical point is going to be repeatability: can you collect the same volume every single time?

Michael
Last edited by datamichael on 01 Jun 2012, 22:11, edited 3 times in total.

Post #4 made 6 years ago
Good Day, I do collect the same amount of wort!
I measured the weight of the damp grains, dried them remeasured the grains and figured I'm losing 0.50L per 2.2Kg of grains or 0.1 quart per pound.

I no longer sparge, since the sparge gravity has been 1.024-1.030 sg.

Squeeze, and Squeeze.
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Post #5 made 6 years ago
Hi there Simplicity,

I just read in your blog that, "I feel that too much of the wort remains in the bag." The first thing to do is see if you actually have a problem so doing a few brews and taking some measurements of water put into the mash and your pre-boil volume are required.

With traditional brewing, you'll lose about 1 litre for every kilo of grain mashed. In BIAB it should be more like 0.6 to 0.7 litres. If you are achieving these figures then you have no problem.

If you are not achieving these figures, then the most likely causes are that your bag is too fine or, far more likely, you are grinding your grain too fine and the resulting flour is reducing your the ability of your bag to drain.

The lateral forces etc, will not be the problem. Your manifold in BIAB is the entire surface area of the bag that contacts the grain - a massively greater area than with a traditional manifold. In other words, you have 'escape routes' for the wort in many directions not just the bottom.

So, check your measurements first to see if there is a problem. Secondly, check that you are not using a floury grist.

;)
PP
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Post #6 made 6 years ago
I'm brewing up a 5 gallon batch of Gumballhead American Pale Ale, and here are some numbers.

Total grain bill = 10 lbs. (4.5kg)
Grain weight after mash/smash = 11 lbs.

So, 1 lb of water left in the grain converts to .119 gallons (assuming 8.35 lbs/gallon), or 15 oz, or (for my metric friends) .45 litres

.45 litres in 4.5kg of grain is .1 litres/kg. Based on PP's post, I guess I should be very happy!

I hit my pre-boil OG of 1.039 on the button.

And of note is the fact that I did not re-crush my grains. My LBSO crushed them for me and I figured I'd see how they did.

Maybe I'm over-engineering this!

MMD21
MMD21

http://www.essentialbrewinginabag.com/

Post #7 made 6 years ago
Good Day MMD21, Great to hear your doing well on the Brew!! Keep us updated on how it goes, and let us help, if your need some.

The "old" 3V brewing has been OVER enginnered, BIAB is so new that no ideas are bad, beacuse we look over anything as it can be good!
Honest Officer, I swear to Drunk, I am Not God.
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Post #8 made 6 years ago
Hi there MMD,

This is one of those weird areas of brewing. Your numbers above which work on weight, would lead you to believe that you lost basically no volume in the lauter however this is not the case.

On your next brew, instead of weighing the bag, measure your volume into the kettle. In other words, all the water you get after the mash including what you drain from the bag. Then subtract this from all the water you put in. For example...

38 L (at mash temperature) before grain added - 35 Litres (after bag drained) = 3 litres

If you had used 5 kgs in the mash, your liquor retained by grain would be 0.6 L/kg.

If you like, also weight the bag and you'll find that the drained bag will weigh just a bit more than the initial grain bill - just like you found above.

It's a weird area and hard to explain well. The best I think I can do is give the analogy of a glass full of marbles. If I added sand to the glass full of marbles, the glass would now be much heavier but the volume remains the same.

To cut a long story short, don't weigh, just measure the volume.

;)
PP
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Post #9 made 6 years ago
Grain Weight vs Apparent Absorption vs Real Absorption

The goal of mashing is to liberate the malt sugars (extract) in the grain and rinse them out

The volume of liquid in your mash is approximately equal to the water you add plus the volume of extract in your grain.

An amount of this liquid is then absorbed by your grain and with drawn when you pull and drain the bag.

Interestingly, if you compare the grain weight pre and post mashing that's not really telling you much because you don't know how much of the sugars have been replaced by water?

Also, the volume difference doesn't really tell you how much liquid you lost to grain absorption because there is other stuff dissolved in the remaining liquid (and in the absorbed liquid)

Anyway, I think your assumption that there is lauter problem in biab is mistaken. I think you wi find, if you check that less liquid is lost to absorption in biab than with traditional methods.

Now you just need to work out how you want to measure it ;)

By weight, apparent absorption (what PP suggested) or real absorption
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 #10 made 6 years ago
[Note: The following is really only for brewers who really want to try and get their head around this area. The last paragraph is the only important thing.]

Stux has actually written what happens in a single paragraph above (just one change below) but I've been trying to think of another analogy for "apparent absorption" as it is a diffciult thing to get your head around. It's difficult as there's a few problems involved...

In metric we are used to the idea that 1000 litres of water weighs 1000 kilogram and occupies in volume, one cubic metre and this is true.

However, adding dry grain/sugar into the mix creates a very different scenario all to do with densities and volumes of solutes and solutes. This makes things very complicated. Maybe the analogy below will help?

What's In the Bag When You Start

When you lower your bag into your mash water, it is like you are lowering a scoop full of a dry mixture of 'dead' matter (hulls, cellulose etc) and sugar into the water. Of this dry grain mixture, about 3/4 of it's weight will be sugar. So if you had a 5kg grain bill about 3.75 kg of it would be sugar. The other 1.25 kg of dry stuff is made up of the super-absorbent 'dead' stuff - a bit like newspaper.

Imagine this newspaper is printed in a soluble gold ink. (We all know gold is very heavy.) The gold ink is the sugar. While it might be 3/4 of the weight of our imaginary newspaper, it does not make up anywhere near 3/4 of the volume of the newspaper.

The Exchange

When your bag hits the water, two things happen...

1. The 3750 grams of sugar (gold ink) dissolve into the water but they don't actually add 3.75 L to the volume of the mash. For example, if you added 3750 grams of pure sugar to say 30 L of water you won't end up with a new volume of 33.75 L. It will be closer to 32.4 L. (The density of a sugar solution is higher than the density of water).

2. At the same time as the above is losing the gold ink, the 'dry newspaper' absorbs a tremendous volume of liquid which is now called "sweet liquor".

What In the Bag When You Finish

After you have pulled the bag, you will be left with "wet newspaper". In other words, the hulls etc have absorbed some sweet liquor, in reality, a bit more than 3750 mls. So, your bag weighs pretty much the same as when you started but now its weight is made up of the original 'paper' saturated with slightly inky water rather than the original heavy golden dry ink.

Apparent Absorption

The above is why this is called "apparent absorption". The reality is, as stux said above, more of an exchange and the density changes are actually even more complex than I have been able to put into the above analogy.

Apparent absorption is the most practical measurement to take and is used in all major software. So, work on volumes not weights in this area.

;)
PP

P.S. Hope some of the analogy above makes sense :smoke:.
Last edited by PistolPatch on 03 Jun 2012, 20:12, edited 3 times in total.
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Post #11 made 6 years ago
Good Day PP, if you have time for science stuff, dry the grains after the sparge/mash is finished, then weight them.

You may see after the Sugar "gold" was washed out, the "new" dry grains DO weight 25% to 35% of the original grain weight.

Not very usable information, but does show why the specific gravity changes.

Have a good brew day!
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #12 made 6 years ago
Would like to see the results of that science experiment :)
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 #13 made 6 years ago
Yeah, I think Josh is exactly right Stu :peace:.

A dried grist will equal the weight of 'paper' originally used (say 25%) plus any sugar (less than 10% for sure even in the highest gravity wort).

I think that if you can get your head around the above, you can see that if your kettle is big enough to put all the water into the mash on a normal gravity brew, then you should.

Existing sparging/partigyle models* are based on totally different liquor to grain ratios and they can only work within certain limits as how solutes and solates work together is not predictable very well mathematically.

We'll have a bit of fun on the brew day next Saturday as we'll be pushing a heap of parameters to their practical limits. I've found that, in a normal gravity brew, it is how much water actually touches the grain that is important rather than when it does.

I suspect a small sparge at very high gravities would make a small difference. I also suspect a large sparge on high gravities would also only make the same difference. On normal gravities, a sparge seems to make only the tiniest difference (for me 1% maybe) compared to full-volume brewing.

We'll see what happens with a high gravity side by side brew next weekend.

:dunno:,
PP

* There are several professionally written articles that talk about "no-sparge" brewing but unfortunately they confuse, "no-sparge" brewing and "full-volume" brewing (passive sparge brewing) and so come to some incorrect conclusions. More confusing stuff and a long story :smoke:.
Last edited by PistolPatch on 04 Jun 2012, 00:12, edited 1 time in total.
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Post #15 made 6 years ago
Good Day PP, I forgot to mention....the difference between the wet Grains(paper) and the Dry Grains(paper) can be used to determine the "Apparent Absorption".

I think you divde the weight deference by the "Speciofic Graivity" of the mash/sparge to get the weight of the water that was aborbed.

Just more measurements than calculations, Numbers is numbers!
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Post #16 made 6 years ago
Good Day Stux, Joshua, and PistolPatch,
Great information. Thanks for helping me understand the obvious, that extracting the sugars from the grains will cause the weight go to down!

I understand the paper/gold ink analogy completely.

Let me contemplate all of your responses a bit more and decide how to move forward.

Cheers.

MMD21
MMD21

http://www.essentialbrewinginabag.com/

Post #17 made 6 years ago
What I have been wondering is does letting the wet bag sit in a colander not accomplish as much as letting it hang?

Is it worth raising the bag, holding it for a minute, then squeezing the crap out of it? Someone suggested pressing it with a plastic pitcher instead of squeezing it. Another person suggested suspending it from a door knob, letting it hang into a bucket, and pressing it against the side.

Is letting it sit on a cake rack a lot better than sitting on a colander? How long will it take to drip out.

I was thinking of mashing at a ratio of 1.25/1 water to grain, then letting it sit in a second pot for a few minutes, stirring, to help get out any trapped wort.

Post #18 made 6 years ago
Good Day ArcLight, Some of us squeeze the "crap" (A technical term) out of the bag.

Some use insulated PVC gloves, Some use two pot covers with insulted knobs, Some use two plastic dinner plates.

There are many ways to squeeze the bags and recover all .11L/kg or .07qt/pound of wort.

Good Luck with trying the Squeeze!
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #20 made 6 years ago
It's been awhile since I had time to sit down and revisit how to measure the apparent absorption of the grains.

After reading through joshua's, PistolPatch's and stux's posts, it seems that I can get a rough estimate of the weight and volume of wort lost to the grains by using the following equations:

Weight of lost wort = [Weight of wet grains after mash - Weight of dried grains after mash] / Specific Gravity of wort

Volume of lost wort = Weight of lost wort (calculated above) / Weight of a unit volume of water (i.e. 1kg/l, or 8.35lbs/gal)

Did I miss something, or do I have it right?
Last edited by makemyday21 on 10 Jul 2012, 08:52, edited 3 times in total.
MMD21

http://www.essentialbrewinginabag.com/

Post #21 made 6 years ago
Good Day MMD21, the formulas look correct. If you find a way to lower the absorbtion, Please let us know!
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Post #22 made 6 years ago
MMD,

Good on you for exploring this MMD :salute:. The more explorers the better I reckon ;).

But, and there is a but, the problem with brewing is that there are so many areas to explore, you can often explore areas that yield no real value. For example, the formulas you are exploring require the brewer having to weigh the grist after draining it (inconvenient) and then dry the grist and weigh it again (impractical).

It's much easier just to measure your water volume in and wort volume out. In full-volume BIAB this is totally simple. Measure the volume before you put the bag of grain in. Measure the volume after you have drained the bag. Easy ;). So, don't let numbers lead you down a complicated path that gives nothing back to you.

As for the formulas, I started looking at these and all these horrific memories came flooding back :lol:. There's a lot more in them than you'd think and I've never thought down this path for too long as it is impractical. Stux, has done a lot of study on this area and he would never tell you to dry your grist and weigh it.

So MMD, don't let this complex area distract you from the more basic questions. e.g. What is efficiency? How many different types are there? What does each different type of efficiency figure actually mean? Can they be useful figures to help me plan a brew or gods I must obey? Do I actually need them? If so, where's the easiest points on my brew to gather the numbers? If they are out of the ballpark, what should I do?

Does that help a bit?

:scratch:
PP
Last edited by PistolPatch on 16 Jul 2012, 18:40, edited 3 times in total.
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Post #23 made 6 years ago
Yes, PP, that helps, however....I am concerned that I cannot measure the volume of wort accurately enough using the homemade graduated mash paddle that I currently use (mostly for filling my pot with water at the start).

A Weight-based approach seems to be a bit more troublesome, but would yield a more accurate result.

I'm not looking to do this for every batch, but would like to get (the requisite) three data points.
MMD21

http://www.essentialbrewinginabag.com/

Post #25 made 6 years ago
Hi there MMD,

The SS rule that steve mentioned is honestly the way to go. The weight-based approach is a theoretical one that to do correctly would require a ridiculous amount of equipment. I haven't thought on it for a while but if my memory serves me correctly, to get any real value from weighing results, you'd actually have to weigh the wort, not the spent grain to get any meaningful answers. And, of course, you'd have to do it over many brews of many different types of grain bills.

Three data points in home-brewing is almost impossible unless you can do all three brews at the same time.

The volume loss from lauter is not a number of huge importance anyway. It's just one of many "in-between" numbers. In other words, it's just one of several numbers between what you put in at the start of the mash and what you get out at the end of the boil. Evaporation rate would be a far more important number to nail down for example as it can vary greatly from brew to brew and from season to season. In other words, you can't really nail that number completely.

Hop/trub management is even harder to guess at the end result.

Efficiency into the Kettle (EIK) can be manipulated in many ways by any type of all-grain brewer. For example, any sort of pressing device and/or time will give you higher efficiency. It's not sensible efficiency though. A more sensible approach to efficiency into kettle is making sure something like your pH is in the ball-park. And measuring that is even tedious. (After 6 years of using pH strips I recently heard that they can be inaccurate. I now have a pH meter and hear they can be inaccurate :lol:)

The first thing is to just brew beer using some numbers that will get you safely in the ball-park. If nothing is obviously wrong, then there's nothing left to explore really. Most brewers will be happy with that and I think that is the correct approach. Some brewers, like you, me and many others like exploring where the number actually come from. This can easily end up being an incorrect approach. You end up trying to match/obey/improve upon numbers you read instead of realising that very little research has been done on most home-brewing numbers. We aren't even asking the right questions yet in many areas.

I do like the way you are thinking but definitely go the ruler before the scales ;)
PP
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