Post #101 made 4 years ago
Cool ;). The only thing I am unsure about now that we are thinking of this as a factor is whether to remove the 0.9614 or not.

The original numbers where we got the factor from came from a relatively small sample size - about 30 brews from about 9 brewers. I'll have to back-track through BIABacus versions to see what the right way to go is I think before we do put out another pre-release.

One aim of the BIABacus was to provide a format where we could better be able to collect numbers so it was never the intention that we would be beholden to any factor or number. This particular factor varies wildly from one brewer to the next so maybe the most important thing is to work out a way of easily explaining what it means which our discussion here have really helped me with at least.

More thinking :scratch: :think: :)
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Post #102 made 4 years ago
PistolPatch wrote:Cool ;). The only thing I am unsure about now that we are thinking of this as a factor is whether to remove the 0.9614 or not.
Don't understand this, atm. This is for the VIB formula, right? If you remove this factor doesn't this bring down the volume to an ambient volume?, which in turn would reduce the 'kettle headspace' in Section T?, displaying a boil volume at a cold volume?
Last edited by Mad_Scientist on 01 Oct 2013, 08:15, edited 2 times in total.
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Post #103 made 4 years ago
Found this from post #38 above;
PistolPatch wrote: VIK is a "hot" figure and therefore must be reduced by 0.9614 to match the other two cold volumes.
If you remove the .9614 from the formula, it would bring the VIB to display a boil volume in Section T?
Last edited by Mad_Scientist on 01 Oct 2013, 08:29, edited 2 times in total.
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Post #104 made 4 years ago
Hey there Richard ;),

Don't get too mixed up or worried about this one as it is something different from those things we were talking about in those earlier posts and does not apply to those.

Maybe the best way to summarise these last few posts here is as follows....

A few brewers were asked over several brews to record how much cold water they started a brew with, how many kilos of grain they used and their volume into boil (not adjusted back to ambient). The error I had made was to reduce that last figure back to ambient which I shouldn't have done as the original figures didn't. (In fact, it gets worse, I actually divided the cold water by 0.9614 as well - see end).

The real lesson from all this though and I might have mentioned it in an off-forum communication with Simon is that, once again, the traditional terminology is not well-defined. When on a traditional brew they say that you'll lose 1 litre per kilogram of grain you use, there are many different ways that this could be read and, in most programs, displacement is not dealt with correctly at all.

...

I won't write anything more here on this subject for a while for two reasons. Firstly I've just had news that I have to drive a truck tomorrow night from Perth to Newman which is 1300 kms away and will probably get caught for a day or two once there.

Secondly, I want a little time to stop and think and ensure the correction being made is sensible and based on the best collection of numbers we have. (Just quickly, the corrected formula is much easier to explain when you see it on the spreadsheet so that is good news ;)). It was only a few minutes ago though that I actually had time to see why the difference between the current formula and the correction is more than I thought it would be. Some other things popped up while writing this but they are all good and correct.

At the end of the day though, no matter how good we make the defaults, the main point is to make sure that the design, structure and help of the BIABacus educates users as fast as possible into what they should be concentrating on when it comes to numbers.

Good question here from maevans on just that type of issue.

:peace:
PP
Last edited by PistolPatch on 01 Oct 2013, 19:55, edited 2 times in total.
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Post #105 made 4 years ago
Regarding this post.
Rick has made one great approach to covering for this lack of info. He has worked on a Bitterness to Gravity Ratio (he's called it BU:GU which means bitterness units to gravity units)) that you can see on the fourth line of Section A.

The only thing to be careful of here is where you base your ratio from. Ratios can be used well or become a gimmick. It is important not to allow them to disguise the real truth. Many styles have a lot of flexibilty. (And, many programs will give you an incorrect ratio as there basic formulas are incorrect or :dunno:). Also, a program will give you wildly varying ratios if you choose Rager or Garetz over Tinseth.

I really am impressed how Rick has approached this recipe. It shows a very high level of understanding of the limitations of recipe reports and the BIABacus. But the 'ratio' approach can also fast turn out to be very ambiguous as well.
Thank you kind sir! I felt like this one was a bit of a softball for me, and whaddya know I learned stuff in the process. :party:

I suppose my only real concrete reference to BU:GU would be my own beer made with the BIABacus, and my taste buds. I suppose it's not a stretch to assume Green Flash is implying Tinseth(or even that calculations are being done the same way I am going about it), but we can't be sure without inquiry. I'll be even more careful about that from now on. I suppose my ignorance to this was helpful to a degree, because I may have delayed brewing if I questioned their IBU values. One more thing I would have had to research before brewing! I really should have picked up on that, though .. grr. Glad it worked out for me, so I dodged a potential bullet there. :cry:
Rick, thanks so much for taking the time here to help S&L out in such detail. I hope you are enjoying doing that. There are a few other guys here that do the same on this numbers side and they will also really appreciate your interest and efforts here.
You're welcome! I do like it, and I'll also do what I can to potentially take the light workload off the more experienced folks. It's the least I can do since I'm being helped as well.
Last edited by Rick on 25 Oct 2013, 22:48, edited 2 times in total.
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Post #106 made 4 years ago
PistolPatch,

Regarding the Sweet Liquor Shop posts, I am wondering about water:grist ratios ... are there some rules of thumb to follow? I know BIAB has a higher ratio 2.25 qt/lb – 3 qt/lb

I was calculating a Pre-Dilution double batch, but in order to do it the BACUS was giving me 57% EIK and a 1.14 qt/lb thickness (pretty thick). I wonder if simply pulling the bag and topping up the kettle would actually give me the 1.068 EOB-SG I'm shooting for.

Perhaps I just need a larger kettle to do this double batch, or perhaps the sparge is the way to go, but I'm wondering how the water:grist ratio influences these methods and if there is a guideline somewhere for using alternate methods of BIAB.
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Post #107 made 4 years ago
Hi there LG ;),

I've just got back from being away but in addition to your question above have read your thread here. Some of what I write below might apply to that thread as well. It's been a long week and so I'm writing the below as much as a way of unwinding as in answering your question. In other words, please don't expect it to be short, written/re-written and edited a million times as I do with some other posts I do here ;).

Point Number One - Available Data

When it comes to extreme mash thicknesses, I don't have much personal solid data on "mash efficiency" and I don't think I have found any, anywhere else. (In fact, you won't find much info on even normal mash thickness mash efficiencies.)

When I talk of "Mash efficiency," I mean the efficiency at the end of the mash. In a full-volume BIAB, mash efficiency would equal your kettle efficiencies (Efficiency onto Kettle - EIK or Efficiency of Ambient Wort - EAW) but in a non full-volume brew that includes sparging, this is not true.

On a brew day here, a few BIABrewer members and myself did an identical recipe side by side. We full-volumed one and the other we mashed at a porridge like consistency (I'll dig up the thread when I get more time.) The weirdest thing was that the extremely thick mash had a lower gravity reading than the full-volume mash. I would very much like to but don't have the time, keg space etc to repeat the experiment as the readings make little sense.

One thing I do know is that existing mathematical models we can find elsewhere on what gravities to expect from high gravity brews are not based on real data. They are based on extrapolations of a small range (or amount) of data. Worse still, brewing software (except for the BIABacus) pretends that you get the same mash efficiencies (and therefore all other efficiencies) from a very high gravity brew as you do from a very low one. This is very much incorrect.

From reading the other thread, I see that you have discovered the BIABacus's auto-efficiency formula. This and the warnings in the BIABacus are going to be your best friend when it comes to making decisions on what to do when you come across a situation where your kettle size is too small to do a full-volume mash.

Point Two - Full Volume if You Can

On the data we have collected here on several side by side brews and through BIABacus results from several members, the current advice is that you should always full-volume your brew if you can.

This advice will seem counter-intuitive, even ridiculous* to many brewers but it actually is totally logical. The data and explanations are here on this forum but I don't write them in ever post I write here. If you want more info on that, just ask. It's probably time I had another bash at collecting the relevant links and writing another "washing machine" analogy. (Until I do, a search of, "washing machine", is bound to give some decent results.)

[*Here is an example of me being quoted on another forum on non-sparging and then being described as having a "complete lack of credibility" :). It's a shame that I don't have enough time to devote here, in a quality way, let alone have time to answer posts like that on other forums :roll:. All the evidence and answers are actually here on this forum but it is really hard to find them unfortunately :roll:]

Point Three - I Can't Full-Volume

Have a read of this post here.

Did you see the bit that said that sparging was almost always a waste of time, effort and equipment? Did you read the next section as well on how a sparge can save you? If so, that last thing is the main point relevant to your question here.

Point Four - Non Full-Volume is All About Juggling

I wrote above that the BIABacus will be your best friend. It will be. It should be able to teach you some things far faster than I can explain them. Your questions above can actually only be answered with the BIABacus and your conscious understanding.

If the BIABacus says your vessel isn't big enough for the brew, you need to consciously decide whether to lower your desired VIF, dilute or sparge. Eithr choice or combination of choice has costs. Only you can decide if the cost suits your situation.

The BIABacus will tell you if what you plan to do is ridiculous or impossible as it throws up a warning. (Careful though as from memory some critical warnings didn't work in some pre-releases). In your situation, you are getting close to being thrown a warning though as 57% EIK is very low.

...

Point Five - A Quick Answer to One of Your Questions.

LG, you asked above, "I wonder if simply pulling the bag and topping up the kettle would actually give me the 1.068 EOB-SG I'm shooting for?"

If you input this into the BIABacus, you will get an immediate answer/advice from the BIABacus.

Do this and then post your BIABacus file into that other thread you have going atm - this one. I'm one of the guys that can say it is okay to post a BIABacus file in a certain thread so just mention you have been given an okay to do so. I think though that you doing so will probably force you to direct your attention to the right areas and maybe your questions here will become null and void? (The BIABacus is the only tool that will tell you if your gravity and volume plan is possible. All we can do is help you to understand how it works.)

Remember, when you stray from full-volume brewing, you enter a complete juggle. This is why existing commercial software has done okay up until now - the juggle disguises everything which makes everything very difficult to prove false or true.

BIAB shines a light on everything - there is nothing to hide behind.

The BIABacus goes further and can juggle the balls any way you want without defying the laws of "brewing physics" like other programs do. You, as a new brewer (or even an old one) don't need to worry about this. All you really need to worry about is if the BIABacus tells you that your brew volume/gravity plan is possible.

...

I'll leave it up to you to distill the above and ask what questions you need to ;),

PP
Last edited by PistolPatch on 11 Nov 2013, 21:40, edited 2 times in total.
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Post #108 made 4 years ago
PistolPatch wrote:Q. If I started with an ambient volume of 25 L of water, heated it to mash temperature, added 5 kgs of grain, pulled the bag and then heated what remained up to boiling point, what would my Volume into Boil be?

A. 25 L TWN - 0.63127 * 5kg = 21.84 L VIB

So, we are wrong to think of either ambient or boiling, we actually need to think of both or, better still neither - see quote below.
Well, for the measurement of VIB that gets recorded in Section L, we do need to think of it as at ambient or mash or boiling temperature, because we have to tell the brewer when to take this measurement. "At ambient" is not practical, because the brewer would have to cool the wort down from mash/mashout temperature to take the measurement, so the VIB should be measured at mash or boiling temperature.

The Brew Day checklist from old versions had the brewer bring the wort to a boil, turn the heat off, then measure the volume. For that reason, I have assumed that I should measure VIB at boiling temperature and not at mash temperature.

We should define this measurement as either "at mash/mashout temperature" or "at boiling".

Or is the expansion between those two points small enough to ignore, so either one could be used?

It occurs to me that the previous measurement in Section L (Mash Volume) also should be defined, this one as either at ambient or at mash temperature.
Last edited by smyrnaquince on 26 Nov 2013, 05:52, edited 2 times in total.

Post #109 made 4 years ago
Ah, you've quoted me way out of context there Dave. That was when we were discussing an entirely different issue (liquor retained by grain) and it related to formulas.

In the BIABacus, when you are measuring mash volume, you obviously measure it at mash temperature. When you are measuring Volume into Kettle, you obviously are measuring it at boiling point.

Easy peasy :P.
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Post #110 made 4 years ago
PistolPatch wrote:Ah, you've quoted me way out of context there Dave. That was when we were discussing an entirely different issue (liquor retained by grain) and it related to formulas.

In the BIABacus, when you are measuring mash volume, you obviously measure it at mash temperature. When you are measuring Volume into Kettle, you obviously are measuring it at boiling point.

Easy peasy :P.
You are right about context. The explanation that went with the equation I quoted specifically states that the VIB would be at boiling.

The "wrong to think of either ambient or boiling" statement kind of threw me, because at that point I was thinking about VIB, which is defined in BIABacus as an at-boiling volume. The volume of the same amount of water would be different at a different temperature. That led me to think about the measurement of VIB that gets recorded in Section L. Then, reading back through this thread, I realized how much we need the companion to the BIABacus that explains the terms, because earlier in this same thread, I found this:
Mad_Scientist wrote:I do miss the VIK and GIK, as it was known to me as 'your starting out gravity at mash temp'. With the VIB / GIB combo, I feel people would think they have to bring their wort up to the boiling point for this one, but it's at mash temp. I check this at mash temp.
Mad_Scientist is measuring his VIB at mash temp, not at boiling.

I'm not sure where the 0.9614 factor being used in BIABacus originates, but using the piecewise-linear approximation to the thermal expansion of water found here, I get that
40 liters at 20C (ambient) would be 41.49267334 liters at 100C (boiling)
40 liters at 77C (mashout) would be 40.55894365 liters at 100C (boiling)
So, measuring VIB at mashout temperature rather than boiling missing 1/3 of the expansion that occurs between ambient and boiling temperatures.

So, throw away all the other junk I wrote and instead let me agree that VIB is an at-boiling volume and suggest that once the companion document is ready, this will be clear to all brewers using BIABacus.
Last edited by smyrnaquince on 26 Nov 2013, 21:52, edited 2 times in total.

Post #111 made 4 years ago
You must be having fun on trying to catch up on this thread Dave, especially areas like the one you stumbled across. MS was doing some variations on pure BIAB but he was correcting volumes for temperature when and where he needed to.

(I hope no newbies are reading any of this! They'll start thinking that there is something really complicated that they are missing. There's not!!! Recording your volumes etc is really easy.)

The thermal expansion we have used comes from a brewing science textbook. We have basically broken down temperatures to ambient, mash and boiling point. This is all that is needed. For example, mash temps would cover anything from about 50 to mash out. The difference in expansion between 50 and 80 c is pretty much impossible to measure on a real-life brew. Simplifying things to three temperatures provides a lot more benefits than having a software where people would have to type in exact temperatures for everything. Furthermore, having a design like that would give new brewers the false belief that they should be exactly matching estimates.

Companion Document

There won't be any companion document. The aim/hope here is to have the whole site work like a book. For some people the BIABacus will act as their initial index but the BIABacus is just one part (a big one for sure), of many parts of information.

You probably want to know when all this will come together. I'll leave that one for Pat.

:peace:
PP
Last edited by PistolPatch on 27 Nov 2013, 20:09, edited 2 times in total.
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Post #112 made 4 years ago
If this has already been found and fixed in the next release of BIABacus, please forgive me. I have not caught up on all the postings.

I believe that the predicted Gravity of Ambient Wort (GAW) calculation in PR1.3I is incorrect.

This is based on my assumption that VIB and VAW are both assumed to be at ambient temperatures for the calculations used in BIABacus. If my assumption is wrong, then please stop reading.

Looking at "BIABacus PR1.3I - American Pale Ale - NRB's All AMarillo APA - Batch 1.xls" from this post, I find:

Section K
VIB = 36.76 liters
VFO = 26.55 liters
VAW = 25.53 liters

Section M
Estimated GIB = 1.0419
Estimated GAW = 1.0580

Because boiling only drives off water, and not sugar, it should be true that:
(Volume * Gravity) before boil
equals
(Volume * Gravity) after boil

Specifically, it should be the case that
VIB * GIB = VAW * GAW
if VIB and VAW are both assumed to be at ambient temperatures (and thus directly comparable).

Re-arranging the math, we should get:
GAW = VIB * GIB / VAW

Plugging in the numbers from the BIABacus referenced above, I get:
GAW = 36.76 * 41.9 / 25.53 = 60.3 (i.e., 1.062)

However, the BIABacus lists GAW = 1.0580

I believe that the BIABacus is incorrectly using the VFO instead of VAW for the GAW calculation, because:
VIB * GIB / VFO = 36.76 * 41.9 / 26.55 = 58.0 (i.e., 1.0580)
which is the estimated GAW given by the BIABacus.

Note that the Gravity at Flameout (GFO) should equal the Gravity of Ambient Wort (GAW), so the calculation depends on the correct volume being used.

If my above discussion is correct, then the GAW calculation in the BIABacus needs to be changed to:
GAW = VIB * GIB / VAW
Last edited by smyrnaquince on 03 Dec 2013, 04:03, edited 2 times in total.

Post #113 made 4 years ago
Relax Dave ;),

The numbers you have above actually do balance. I'm short on time for at least the next day but if I get a minute later today I'll pop up the maths. It's easier than you think :party:.
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Post #114 made 4 years ago
Well, I get

VIB * GIB = 36.76 * 41.9 = 1540.244
VFO * GAW = 26.55 * 58.0 = 1539.9
VAW + GAW = 25.53 * 58.0 = 1480.74

The 1st and 2nd match, which tells me that the GAW was estimated using the VFO.

I believe that the 1st one and the 3rd one should match because they both reference ambient volumes. VFO has expansion due to heat, which would throw off the calculation of the estimated GAW.

However, I've been wrong before. No hurry, but when you can, let me know what I am understanding incorrectly.

Post #115 made 4 years ago
smyrnaquince - That file has maxi adjustments in it. Be careful when doing comparisons when there are dilutions etc.

If you remove these you should see the numbers are close (they are rarely exact) but close enough.
G B
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I've stopped drinking, but only when I'm asleep
I ONCE gave up women and alcohol - it was the worst 20 minutes of my life
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Post #116 made 4 years ago
Going to be short on time for at least a few more days now but...

VIB is not an ambient volume (same goes with VFO). It is exactly what it says - Volume into boil*. (I thought we had that cleared up a few posts ago?) So, you need to adjust your VFO (36.76) to ambient (35.34). Now you'll see your numbers balance.

Cheers mate ;).

* It would be a pretty crap design if we asked people to measure VIB and then asked them to convert it to ambient and record it as an ambient number but record it as an ambient :o :P.
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Post #117 made 4 years ago
mally wrote:smyrnaquince - That file has maxi adjustments in it. Be careful when doing comparisons when there are dilutions etc.

If you remove these you should see the numbers are close (they are rarely exact) but close enough.
The file I referenced has no maxi adjustments in it.
PistolPatch wrote:VIB is not an ambient volume (same goes with VFO). It is exactly what it says - Volume into boil*. (I thought we had that cleared up a few posts ago?) So, you need to adjust your VFO (36.76) to ambient (35.34). Now you'll see your numbers balance.
Um, er, ah...

I am so mad at myself that I keep getting this wrong.

The terminology threw me. Because GAW is Gravity of the Ambient Wort, I grabbed the VAW (Volume of Ambient Wort) for my calculations.

Because VIB and VFO are both measured at boiling temperatures, they are directly comparable. You can't compare VAW with VIB without taking a temperature compensation into account (as Pat pointed out).

The gravity at flame out is the same as the gravity after the wort has cooled, so, the numbers do indeed agree:
VIB * GIB = 36.76 * 41.9 = 1540.244
VFO * GAW = 26.55 * 58.0 = 1539.9


In my (lame defense)...
smyrnaquince wrote:This is based on my assumption that VIB and VAW are both assumed to be at ambient temperatures for the calculations used in BIABacus. If my assumption is wrong, then please stop reading.
I'll try to keep quiet now...
Last edited by smyrnaquince on 04 Dec 2013, 02:15, edited 2 times in total.

Post #118 made 4 years ago
No need to apologise Dave :nup:,

So many brewing numbers are really complex it is easy to forget which areas are relatively simple and which are hard and tricky. There are many areas that are so difficult, you actually have to "re-learn" them every time you want to check them. I often have to consciously stop and ask myself, "Is this an easy or hard area?"

So, it is really easy for any of us to miss what might seem obvious when someone else points it out. For example, mally mentioned that the file might have had maxi-BIAB adjustments in it. You replied that there weren't but the real issue is that whether or not there were maxi-BIAB adjustments or not, is actually totally irrelevant. You can put in as many maxi-BIAB adjustments as you like and your numbers will always balance.

In other words, when you fill in Section B and C, one key question the BIABacus is asking is, "How much 'sugar' does this brewer need to get this result?" In a normal all-grain brew, that 'sugar' has to be added before the boil begins. It doesn't matter whether you sparge or dilute, the BIABacus will always be forcing thing s so as you have the correct amount (weight) of sugar in the wort at the start of the boil. This weight will not change during the boil.

(I think both of you know the above but it is not 'automatic knowledge' to you yet, if that makes sense.) The above is really easy to forget and it took me quite some time for it to become automatic for me as there are just so many things you are learning at once when you step into advanced number knowledge. And, of course, we have had no one to actually teach us this stuff well because a lot of it we are actually pioneering here.

...

The other common one which I don't think would apply to you or mally at this stage is when people have an 'efficiency' problem, they sometimes say, "My boil was really just a simmer, maybe that caused it?" The answer is, "No", as once again, the weight of sugar in the boil is not affected by the evaporation rate.

So Dave, no need to keep quiet. Even if only 1 out of 10 of your questions highlights a problem, it is sure to be something very important and the other nine force us, at the very least, to double-check that the 'help' that is planned will cover your point.

And please, if you see a post on the board to which you know the answer, take it on ;).

:peace:
PP
Last edited by PistolPatch on 05 Dec 2013, 17:57, edited 2 times in total.
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Post #119 made 4 years ago
[smyrnaquince, I am doing a consecutive post here so make sure you haven't missed my post above ;)]

The following is advanced stuff that I want to make you experienced guys aware of.

Anyone reading this thread should now be well aware that the higher the OG demanded of a brew, the lower the kettle efficiency but as has been stated previously and as Mad-Scientist remembered to write today in another thread... "The BIABacus auto-efficiency may be off on big gravity brews."

Anyone reading this should be very familiar with posts written by me that contain any of the following...

"Washing machine"
"Cup of coffee"
"Tea"
"Kettle efficiency"
"Fermentor efficiency"
"jeans"
"Sweet Liquor Shop"
etc (we all know it is a hard area to articulate/analogise)

Anyway, Mad-Scientist's taking on board that other question inspired and gave me some time to draw up a pic of what BIABrewer really thinks the auto-efficiency equation should be. Here's the pic...

Kettle Efficiency versus Gravity
Efficiency versus Gravity.jpg
I don't think I have the curve embellished enough but there is no way I can until we collect more figures.

What I am trying to say though, through the pic, is that the BIABacus auto-estimates/corrections, excellent though they are, will still be under-efficient (I mean 'kettle efficient' obviously) on low gravity brews and over-efficient on high gravity ones.

As MS said in that other thread today, we need more people doing extreme brews and recording their numbers. Without real, honest numbers from many more brewers, there really isn't much more to say.

:peace:
PP
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Last edited by PistolPatch on 05 Dec 2013, 20:21, edited 2 times in total.
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Post #120 made 4 years ago
Sorry, my bad.
Having looked at the file (and seeing the maxi 10L into fermenter as well as 10L used in a sparge), I just presumed we were looking at the PLG stuff MS discussed a few pages back.
I will admit to not knowing how GIB's and GAW's are calculated in the BIABacus though!
G B
I spent lots of money on booze, birds and fast cars. The rest I squandered
I've stopped drinking, but only when I'm asleep
I ONCE gave up women and alcohol - it was the worst 20 minutes of my life
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Post #122 made 4 years ago
Good stuff mally ;).

aly, I'm not really sure on this as we have gathered almost no actual numbers on very high and very low gravity beers and there certainly aren't any floating around anywhere else on the net.

My best guess is that you could consider that straight line part of the above curve as being from about 1.035 to 1.065. Below and above these numbers we would expect the actuals to start diverging from the linear BIABacus kettle efficiency auto-estimates gradually and then more and more rapidly.

Bear in mind though, that we have set the default BIABacus kettle efficiency auto-estimate a little low so as the most likely result of a brew is that the brewer will end up with a slightly higher gravity result which they can then dilute. So, I don't think this area is anything to worry about until you start brewing say above 1.070, as the safety margin in the default would probably cover you up to that. Very hard to tell though atm until we get some more figures.

One thing I should have mentioned is that we should never forget about time (and other factors) that also affect kettle efficiency. Leave a high gravity brew for a day at the right temperature and who knows what kettle efficiency you will get? But, also imagine how many tannins and other undesirables might have leached out of the husks by then :shock:.
Last edited by PistolPatch on 06 Dec 2013, 19:21, edited 2 times in total.
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Post #123 made 4 years ago
Thanks. :thumbs:
PistolPatch wrote:Anyway, Mad-Scientist's taking on board that other question inspired and gave me some time to draw up a pic of what BIABrewer really thinks the auto-efficiency equation should be. Here's the pic...
Only a gut feeling, but I'm suspicious about the tail-out in the bottom right where the curve gets less steep and starts getting closer again to the straight-line approximation. I would expect the efficiency to continue to get worse and not slowly get better again. In other words, I wouldn't expect an inflection point.

Again, just my gut feeling, but I don't see why the shape of the curve would change down there.

As you point out, we need real data to get an idea of what is really happening.
Last edited by smyrnaquince on 07 Dec 2013, 02:50, edited 2 times in total.

Post #125 made 4 years ago
Richard: Talking about numbers etc looking easy in hindsight, your posting of that graph certainly proves that point :). That old graph*** was trying to say exactly the same as the new graph but how bad is it? I just couldn't get it right back then :lol: (I've put an edit on the old post now linking to the new graph ;)).

Dave: The kettle efficiency actually never gets better from left to right - it is always getting worse. The 'tail-out' you mention is actually the kettle efficiency getting worse much faster. Here's more of an explanation...

At the top of the graph, we are looking at grain being soaked in lots of water. Past a certain amount of water, you will be getting all the sugars out. In other words, whether you soak a grain of malt in a glass or a bucket of water isn't really going to make any difference - you have used more than enough water in either case to 'wash' the sugar out of the grain.

At the bottom of the graph, the bit you mentioned, we have grain being soaked in bugger all water. Imagine you had 5 kilograms (11 pounds) of grain. Whether you soaked it in 1 liter (1 quart) of water or just spat on it would make no difference. Your kettle efficiency would still be zero as all that liquor would be retained in the grain - you'd never get it out.

And Dave, don't even look at the old graph that Richard posted :lol:,
PP

*** I just remembered why I found that first graph so hard to draw. Back then, my main focus was working out how to introduce a time factor into the kettle efficiency equation so I was trying to think in three dimensions. No wonder I couldn't draw the bloody thing :)!
Last edited by PistolPatch on 07 Dec 2013, 20:43, edited 2 times in total.
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