Having 4 would be nice. I don't know about the layout though.

As it stands with PR1.3H, there is a missing corresponding volume, that is VFO, the old EOBG.

The old PLG was/is a redundancy for pure biabers, GIK (old)/GIB matches PLG in that case (after the mash and bag drain).

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.

With an end of boil gravity, folks can pull a gravity sample just before flame out, like me. I like GAW. I worry what the gravity will be when it cools down, so this is very nice.

I like in Section M;

VIK <=> GIK
VFO <=> GFO
VAW <=> GAW

Don't like (maybe in Section W);
GAM <=
PLG <=

Mad_Scientist wrote:

PistolPatch wrote:PP, I didn't know that the PLG formula was flawed in your opinion. I know it was a pita trying to wrap my arms around why I wasn't hitting that estimated gravity, and I don't sparge.

Unfortunately, there is actually nothing wrong with the PLG formula if you treat it as the gravity after the bag is pulled for the final time. In other words, if you call it Post Lauter Gravity.

1. For a full volume BIABer, they have the luxury of being able to measure it just before they pull the bag or afterwards. This assumes they do not let the bag drain somewhere and then add a few more dribbles of sweet liquor in later.

2. A person who does a pre-boil dilution has the same luxury as the pure BIAB'er but they must measure the gravity before they do their post-boil dilution. (This si what you do and so your problem has not gone away sorry).

3. The person who mashes and sparges though, can only take their Post Lauter Gravity reading after they have mixed their first running with the runnings from their sparges.

The formula does not work in case number 3 if the person wants to know the gravity of their first runnings.

The long and short of all this is that the number is fairly useless except for the person doing a pre-boil dilution like yourself.

So, the formula should be working for you but isn't. When you take your sample, are you covering and cooling it to room temperature? Is it free of debris? Is your hydrometer jar wide enough? Are you adding in more runnings that have drained from the bag as it sits in the bucket waiting for the boil to begin?

Any of those things happening?


PP

P.S. I can see that there are lots of other questions above from Dave. Might have to get to them later.

PistolPatch wrote: So, the formula should be working for you but isn't. When you take your sample, are you covering and cooling it to room temperature? Is it free of debris? Is your hydrometer jar wide enough? Are you adding in more runnings that have drained from the bag as it sits in the bucket waiting for the boil to begin?

Any of those things happening?


PP

I feel that my method of taking and measuring a sample for testing is pretty good. I am a refractometer user, with ATC. I make the best effort of getting a 1 tablespoon sample and put it in a test tube and cap it. After a while when the solids have dropped to the bottom I carefully pour the clear wort into a stainless steel tablespoon measure, that I use for my coffee. I draw out a sample and return a couple of times to mix it up good. I take a reading, maybe twice.

With the PLG yesterday, I took a 2nd sample. Two tablespoons into a pint canning jar and sealed it up.

My readings are still coming in low, compared to the BIABacus. I got a 1.065 and the BIABacus says a 1.071/4.

I posted all my findings again over on the simple experiments thread again.

Relating to the PLG about volume, I have made some observations over the last 3 brews. The post lauter bag pull after squeezing comes real close (but slightly low on volume) to the end of boil headspace mark on my sight glass. Joshua would be real proud of me, I came up with a method of squeezing the bag to get to this volume mark. Sorry, no pictures, my hands were full, basically it's a bear hung...

The formula used by BeerSmith is......

sg = sg_measured + sg_measured * (1.628E-5 * (tc - t) - 5.85E-6 * (tc*tc - t*t) + 1.532E-8 (tc*tc*tc - t*t*t))

where sg_measured is the measured value, tc is the calibration temperature and t is the temperature (both in celsuis the sample was measured at.


This is just off the top of my head.... Not copied from a Brad Smith news letter! I love math and numbers

Sorry to interrupt this fine post but I thought the info would be nice so PP could correct Brads formula!!

And that temperature correction formula is a correct one from memory Bob but...

I'm going to have a bit of a dummy spit here because I still have a few PM's/emails and threads here I want to respond to. Usually I do them first and never get a chance to have a dummy spit.

If I had the time to do a complete dummy spit here, I would show you all the mistakes and errors in all the brewing software out there and how much study and time it took me and a few others to find. Finding the things was just the thin edge of the wedge. Even the biggest selling software which BIABrewer spent many hours over many months trying to help has still only fixed a few of its most basic errors.

If you want to know what the errors are and how bad they are, start a thread.

I think I am pretty much in cranky mode atm and might remain here for a while. It's totally ridiculous we have all this knowledge here that we can't get distributed.

PP,

It will happen! It will take a bit more sweat and tears to get it done. But when it's near completed (it never will be completed) Remember that you have a meeting with the media (you know who) that will spike the interest of many and give you a sounding board to (gently) poke at the other software's. You just have to say the word!

PLG Formula ?

I just found this formula tonight and plugged in my numbers. It looks like this formula perchance exactly matched up to my numbers from

my last brew day; viewtopic.php?f=33&t=1669&start=50#p31730


http://byo.com/stories/item/237-blendin" onclick="window.open(this.href);return false; ... techniques
"To completely master high-gravity brewing calculations, all you need to know is one simple formula:

C1V1 = C2V2

where C is concentration and V is volume. The subscripts refer to the initial strong beer and resulting blended beer."

Following this example, I am interpreting this as a dilution that can be used for an "initial" concentrated wort (Pre-Lauter Gravity - PLG)
and the "resulting" pre-boil dilution (Gravity into Kettle - GIK)

These are my numbers;
For calculating gravity, use “gravity points” — the decimal portion of specific gravity as an integer. For example, a specific gravity of

1.065 equals 65 “gravity points.” If you had 11.28 gallons (42.72 L) of wort at a specific gravity of 1.065, what would the gravity become

if you diluted it to 12.65 gallons (47.88 L)? Substituting the values into the equation, we get 65(11.28) = X(12.65). Solving for X, we

get 65(11.28)/12.65 = 57.9, or a specific gravity of almost 1.058. You can also use degrees Plato for these calculations.

Bob: What I'm annoyed about is that while we spend so much time here explaining and answering questions relating to problems caused by other programs, it steals time away from working on the site and perhaps creating our own coded program that could reward/finance the site. Meanwhile, while we are answering the questions and creating pretty amazing solutions, whose to say someone isn't sitting back right now and copying all this hard work? Anyway...

Richard: Think we have discussed this formula somewhere else already - can't remember. You will find though that the formula above matches what the BIABacus tells you. So, if that formula is working on your last brew, then theoretically it should have worked on all your other prior brews.

You can not only use plato in the above formula as you mentioned, but you can also use liters as well. Look at the attached file.

VIB = 36.76 L which when cooled to ambient = 35.34 L
Water Added Before the Boil = 10 L
Therefore, Water Used in the Mash = 25.34 L

Estimated PLG = 1.058/4 (In this file it is called GAM)
Estimated GIB = 1.041/9

25.34 * 58.4 = 1479.9
35.34 * 41.9 = 1480.7

In other words, both match. This is why your numbers not matching has had me scratching my head a lot. There is definitely no error in the formulas .

Good to see the last numbers added up .
PP

PistolPatch wrote:Bob: What I'm annoyed about is that while we spend so much time here explaining and answering questions relating to problems caused by other programs, it steals time away from working on the site and perhaps creating our own coded program that could reward/finance the site. Meanwhile, while we are answering the questions and creating pretty amazing solutions, whose to say someone isn't sitting back right now and copying all this hard work? Anyway...

It may be cold-hearted, but there are forums for those other programs. We could just refer people to those forums for questions regarding those programs.

PistolPatch wrote:
Richard: Think we have discussed this formula somewhere else already - can't remember. You will find though that the formula above matches what the BIABacus tells you. So, if that formula is working on your last brew, then theoretically it should have worked on all your other prior brews.


VIB = 36.76 L which when cooled to ambient = 35.34 L
Water Added Before the Boil = 10 L
Therefore, Water Used in the Mash = 25.34 L

Estimated PLG = 1.058/4 (In this file it is called GAM)
Estimated GIB = 1.041/9

25.34 * 58.4 = 1479.9
35.34 * 41.9 = 1480.7

In other words, both match. This is why your numbers not matching has had me scratching my head a lot. There is definitely no error in the formulas .

Good to see the last numbers added up .
PP

Hey PP, That is a nice visual of what is going on!

I am happy I 'balanced' this time. With a sight glass attached to my keggle, I have some volumes pre-marked before the brew starts. The PLG is measured ad hoc. Both my VIB and Post Bag Pull Volume are measured at a mash out temp, about 170 F.

So, after getting this post of yours and studying my file, I have a follow-up Pre-Release question.

Why am I NOT getting this very low volume on my Post Bag Pull? It's a 4 L difference.

These are my file estimates;
VIB = 47.88 L which when cooled to ambient = 46.03 L
Water Added Before the Boil = 7.5 L
Therefore, Water Used in the Mash = 38.53 L

Estimated GAM = 1.071/4
Estimated GIB = 1.059/8

38.53 * 71.4 = 2751
46.03 * 59.8 = 2752


These are my actual numbers;
Water Added Before the Boil = 6 L
(I had 1.5 L I didn't need)

GAM = 1.065
GIB = 1.058

Post Bag Pull Volume = 42.72 @ mash temp
VIB = 47.88 @ mash temp

Some good news . The powers that be think that the BIABacus, terminology etc, etc are up to scratch and so we can get on with a final push. This will mean a lot of work and so to avoid getting distracted from the bits I can help with, I am going to preferably only post in this thread. Hopefully you guys can handle the recipe scaling questions etc. If Bob doesn't help out, make sure he at least writes funny stuff .

...

Dave, I'm going to have to skip answering your questions from a few posts ago sorry but the answers are out there somewhere. Basically, the most practical way of measuring VAW is by measuring KFL and VIF. It is rarely practical/possible/advisable to measure it in the kettle once chilled.

Regarding sending people to other forums to get software questions answered, there are two interesting points here. Firstly, if their question relates to a program formula or design problem, from what I have seen, the question is usually avoided or, I think the word might be, obfuscated. But, more importantly, most questions here actually don't relate directly to other programs, they more relate to the poor terminology currently used everywhere in the home brewing world such as 'batch size' and 'efficiency'.

What the powers that be want to do (and have always wanted to do) is get some structure to the site so as people can find answers easily rather than getting individual answers as currently happens. First though we have had to come up with answers that would work for everyone. This was a lot harder than anyone could ever have imagined.

...

Richard, thanks for your post above and for all the figures you have been taking. I've said it before, they make a real difference. As a matter of interest, in your post above, when you take the volumes back to ambient, Litres by Gravity Points was 2722 Post Lauter and 2670 after dilution. In other words, they are the same.

One main thing that your questions on this, and especially your last post here has taught me is that we should either remove PLG (GAM defintely is going as we can't get a good formula for it atm) or add a PLV (Post-Lauter Volume). It is your posts that have made that clear and I should have seen it ages ago sorry. Basically, I never stopped and compared your actual Liquor to Grain Absorption Ratio with the estimate.

I am 100% certain that the right decision is to get rid of PLG in the spreadsheet version. If we ever do a coded version, then numbers like PLG, PLV and GAM could be available if needed but hidden by default. Including them in the spreadsheet version I think just adds unnecessary complexity. The less of that the better!!!

I also think I have been subconsciously hoping this PLG problem would go away because getting rid of one line in the BIABacus now means a whole lot of visual design problems need to be considered. Bugger!

I better go and consider them.

...

Myself or Pat will keep you posted of anything interesting that pops up and will probably send a few of you a final BIABacus release file to check over.


PP

P.S. When the powers that be suggested I only post in this thread, I don't think they meant writing an essay. Whoops . Please do your best to keep me out of here .

PistolPatch wrote:... I also think I have been subconsciously hoping this PLG problem would go away because getting rid of one line in the BIABacus...

Dave, getting rid of PLG actually made a bit more space to deal with your end of boil volume measurements. It still doesn't solve the rare situation where someone actually measures their VAW directly (ambient wort or end of boil volume once cooled) as in via a sight glass but the extra line does allow for a lot more information to be conveyed.

Please check this version out thoroughly because I don't think we can do much more than this one apart from getting the ? hyperlinks done.

PP,

OK, from what I can tell "Once chilled, VAW should be approx" is calculated as VFO - shrinkage

and

"Volume of Ambient Wort (VAW)" is calculated as VIF - KFL.

So, for my situation, where I put my ruler into the pot after chilling and directly measure the VAW, I could simply transfer the wort to the fermentor, measure and record VIF, then adjust my KFL to hit my measured VAW.

Now, the GAW should be the same for both the "Once chilled, VAW should be approx" and the "Volume of Ambient Wort (VAW)", so that is no problem.

From what I can see, the EAW is calculated off of the "Once chilled, VAW should be approx" unless there is a VAW, in which case the VAW is used. If this is correct, then good, that is what I would expect!

Playing around with the BIABacus to verify the above made me look more closely at KFL...

The brewer can enter VFO, KFL, and VIF. The once-chilled VAW is calculated from the VFO. So, if there are no unexplained losses, we should have:
Once-chilled VAW - KFL = VIF
However, I can enter anything I want for VFO (which yields the "once-chilled VAW"), KFL, and VIF. If I enter a KFL, shouldn't the VIF be calculated? No, because the "once chilled" is an approximate value, an estimate. So, the math is not guaranteed.

Now, VAW - KFL = VIF is guaranteed. The problem is that the brewer might measure any 1, 2, or all 3 of these quantities. AFAIK, Excel does not let me say "calculate this value unless the user has entered a value in the cell", so there is no good way to allow me to measure and enter any of those values that I want.

Given that Excel limitation and that it seems that few people actually measure the VAW, it seems reasonable to have the spreadsheet the way you do. If I measure, say, VAW and KFL, I can simply adjust my VIF until the calculated VAW matches my measurement. (Given that I use a ruler on my cylindrical kettle, but that the markings on my somewhat tapered fermenter are approximate, this is probably what I will do.)

As far as I can tell, if I enter a VIF and KFL, thus getting a VAW, I do not need to measure the VFO because no calculation will require it. VFO is only used to calculate the "once-chilled VAW" and that value is not used anywhere if I have a VAW (by entering a VIF and a KFL). Is that correct? (If so, then this is all holding together nicely.)

for your recent updates!

Ha! My head is spinning .

No, seriously, what you have written is correct except for the third line where you've made a typo. It should be VAW = VIF + KFL.

On release it will be much easier as the user will just click on the question mark and see the different ways in which they can measure and record their VAW. As you have indicated above, if a user took both a hot VAW reading and one based on VIF + KFL, the BIABacus gives priority to the latter as it is generally easier to measure and therefore more accurate.

Having a few ways of measuring VAW is another example of a principle of the BIABacus that allows a series of double-checks on measurements.


PP

Yes, sorry for the typo.

I typed in a longer response yesterday, but it seems to have disappeared. I'll just get straight to the questions I ended with on the missing post:

The BIABacus priming sugar calculator does not agree with the TastyBrew one I typically use. I don't know what formulas either one uses and I don't know which is right, so I am just pointing out the discrepancy.

There is another issue with the priming sugar, though. The amount of sugar needs to take into account the retained CO2 in the beer, based on the temperature of the fermented beer. As best I can tell, BIABacus uses the temperature from the first line in Section H. I recently brewed a witbier, which starts at one fermentation temperature, but ends at a higher one. I enter the lower temperature into Section H, but there is no place to record the target final temperature and that final temperature is not taken into account in the priming sugar calculation. I tried using the diacetyl rest temperature for this purpose, but that didn't do it. I believe that Section H needs to have a place to enter beer temperature at bottling time for the priming calculation. It would be nice if it also let me record the fermentation temperature schedule.

Dave, this is one of those areas that popped up while you were on hols. I just got side-tracked on a few things and so I better be really quick here. Let me know if the following links help...

http://www.biabrewer.info/viewtopic.php ... ing#p20842 - Maybe even go to the beginning of that thread as that is probably where the conversation started?

http://www.biabrewer.info/viewtopic.php ... ing#p24200 - Look like that leads to some answers.

http://www.biabrewer.info/viewtopic.php ... ing#p30081 - My current thoughts on priming formulas. (Read my post prior to that as well in that thread.)


PP

First, I do think that BIABacus is missing the fields that would allow me to enter a fermentation schedule like this one, from the Wittebrew recipe in Brewing Classic Styles:
"Begin fermentation at 68F (20C), slowly raising the temperature to 72F (22C) by the last third of fermentation." Either this has to go in Setion I Special Instructions (and not be taken into account in the priming calculation) or new fields are needed to allow the brewer to fully record the recipe.

OK, I read the threads you referenced. My take-aways:

• Some of the carbonation calculators don't take into account "trapped" CO2. If they don't use temperature as an input, they don't take that CO2 into account.
• The calculator has to take into account the final active fermentation beer temperature before bottling.

In the Batch Priming thread:

PistolPatch wrote:One of the many things Yeasty mentioned in his excellent post above was temperature. Basically, the warmer the temperature, the less CO2 can be held in solution in the 'fermented wort'. Just keep your answer here simple. If the last few days of active fermentation were around 18C then type that in. If you did a diacetyl rest on a lager at 15 C for a few days, then type that in.

From my experiments with BIABacus, changing the diacetyl rest temperature did not change the amount of priming sugar. BIABacus is missing what you said in this post. A bug?


In the Consensuson Temp to input when using a priming calculator? thread:

PistolPatch wrote:The Temperature Question - Understanding the Science

I think there are two things that we need to understand here which then make everything else a lot easier.

The first thing we need to do is understand that cold wort can hold more CO2 in solution than warm wort.

The second thing to understand is that CO2 must be getting actively put into the beer. In other words, if there is no fermentation activity going on you will not be able to increase the CO2 levels.

[further comments dealing mostly with lagering]

So, for my situation, a witbier fermentation where the temperature rises over the course of 3 weeks, the active fermentation that is putting CO2 into the wort would be in the earlier part of that 3 weeks. The warmer temperatures near the end would not hold as much CO2, so I should use the final temperature for my priming calculation. BIABacus does not seem to currently allow me to do that.


In the Consensuson Temp to input when using a priming calculator? thread:

PistolPatch wrote:

PistolPatch wrote:...I rarely bottle but when I do need a bottle I use 2 carbonation 'lollies' per 740 ml. This is 7 grams of glucose. These seem to work out nicely regardless of what I am bottling - usually pale ales or lagers.

However, if I use the priming formulas such as used in the BIABAcus, if I put in 2.5 Vols of CO2 and a fermentation temperature of 37 C (the temp that causes the formula to give the highest result) I still only get told to use 4.7 grams of corn sugar which is the equivalent of only 4 grams of glucose...

So, the more I look into this, the more suspicious I am of just what science these formulas are based on.

Since posting the above, I have had two more bottles (lagers) that I had used two carbonation drops in. Carbonation result? Perfect!

If the formulas we are currently using in the BIABAcus are correct, my beers should have been tremendously over-carbonatred, certainly not, 'just right'. Looking forward to hearing whether your beers turn out frothy, just right or flat.

If they turn out flat then that is at least two of us the think there is a problem ,

PP

So, as of April 17, 2013 (date of the above post), carbonation drops were working for you, but the BIABacus priming calculator was still in question.

Is priming a dead issue or just on the back burner? Or did I miss the resolution to the question?

Yep, the BIABacus (and most other brewing software) does not allow for multi-stage fermentations. If they do, it is just a list of temps and times at best - it doesn't affect anything. Of course, we could not do that in a spreadsheet without allowing a heap of lines that would very rarely be used. So, as you say, in the rare case where there are extra steps write these steps in the Special Instructions section. Things like that are exactly what it is for and anything that gets written there gets displayed in the Recipe Report.

...

There might be more info if you search my posts for diacetyl but the diacetyl rest is not the last stage of fermentation. When you lower from the rest, the beer should still be actively fermenting so that last temperature at which it is actively fermenting will be lower than the diacetyl rest.

Play with these numbers in the BIABacus and you will see it doesn't make much difference anyway.

...

As for there being a resolution as to the actual formula, I don't think there is one atm. We'd need more info from bottlers to find out what works for them. One thing I do know is that you shouldn't believe some formulas you see bandied about as they are often faulted in some way. Priming is certainly one formula I am dubious about but the BIABacus one has been the best we can do to date.


PP

Hi again, been a while since I've posted - few more brews under the belt, meaning more figures to ponder. One weird thing I've come across is a possible discrepancy in the way "Volume Loss from Lauter" is calculated, and my apologies if this has been discussed before (I did do a search), or if I am just not seeing the forest for the trees.

I have seen it said a few times on this board and others that BIAB grain absorption is 'around 0.6 to 0.7 L/kg'.

And (to refer to a program we know has errors, but I believe its numbers come from people from this board), Beersmith tends to agree, being set at 0.6113 L/kg by default.

But, taking the Amarillo APA as my test case, I get different figures.

Now, I'm not sure if BIABacus applies the ratio to Ambient Volume of water (TWN) or Strike Water Volume (SWN), but I get these numbers:

TWN: 2.36L absorbed for 6.013kg of grain - 0.3925 L/kg absorption
SWN: 3.14L absorbed for 6.013kg of grain - 0.5222 L/kg absorption

So from these numbers it seems 0.6 is not what is used. However, the plot thickens when I SET Volume Loss from Lauter to 0.6.

TWN: 2.19/6.013 = 0.3642
SWN: 2.96/6.013 = 0.4923

Neither of which is 0.6!

Obviously I'm missing something pretty basic here - can someone explain what numbers I should be looking at to ascertain the default Volume Loss To Lauter figure in BIABacus, and whether it is applied to TWN, or SWN?

Cheers!

Simon

Howdy Simon ,

This could be some more terminology that is a bit ambiguous - will think on it later but there are two things going on here....

[Just quickly, BeerSmith should have the same figure as the default number was provided to BeerSmith by BIABrewer.info. I think though that their number has been distorted a tiny bit by being put into US measurements as the base. 0.6113 should actually be 0.628 - not a big deal though.]

The two things we are looking at are:-

1. How much the volume of wort increases when we add the grain. This has no name in the BIABacus as it doesn't need to be adjusted. Basically, if you add 5kg of grain to the strike water, the volume will go up by 3.75 L. In other words, the wort increases by about 75% of the volume of the grain bill.

The above only has relevance to SWN and Mash Volume, nothing more. Think of this as displacement.

2. What we call Volume Loss from Lauter in the BIABacus is different from the above. It actually means how much of the SWN is retained in the grain after the lauter (bag pull). The volumes get a bit messy to work out as we have to deal with expansion however, the basic formula (assuming no dilutions) is TWN = 0.628 x Grain Bill in kg + VIB * 0.9614. We can re-write that to VIB = (TWN - 0.628 x Grain Bill in kg) / 0.9614.

What this is saying is that say if you had a brew (very unlikely) that had a TWN of 50 litres (which expands to a SWN of 50.99 L) and you were going to be using 5 kgs of grain, then after you pulled the bag from the 50.99 lts of what is now 'sweet liquor', you will end up with 48.74 L going into the boil....

0.628 * 5 = 3.14 L at ambient

48.74 L at boiling = 46.86 L at ambient

50 L - 46.86 L = 3.14

Nice and confusing eh?

I'll attach a file here that may help a bit as it has the above numbers in it. Hope this helps you to understand a really confusing area Simon.


PP

Righto, got it - at least got the way it's calculated by BIABacus. Not confusing at all, just never considered the possibility that VIK/VIB at ambient would be part of the calculation!

So - the calculation is applied to ambient volumes. So for my example above:

TWN: 39.12L
Ambient volume into Kettle/Boil (which never really exists!) = (36.76*0.9614) : 35.34L

39.12-35.34 = 3.78L absorbed

3.78/6.013 = 0.6286 (Voila! Close enough given rounding errors)

BUT - in my experience this is not how it works. Other programs (the ones we love to hate), apply the 0.6 to TWN and VIK/VIB (non-ambient), and this actually seems more accurate to me. Anecdotally, using BIABacus numbers, I have to squeeze the bejeezus out of my bag, and still fall short of the estimated VIK/VIB. Using BS, a mildish post-pull bag-squeeze does the trick. Applying the number to the ambient volume of the VIK/VIB amount seems counter-intuitive too, as ambient volume of the VIK/VIB never ever exists.

Anyway, just my 2c.

As per previous posts, BIABacus more often than not doesn't suit the recipes I brew anyway. Knowing how it works as per above, I could always adjust BIABacus's 'number' for Lauter loss, so it equals what I expect it to equal, but again, other programs already work the way I expect, so there's probably little point. A shame, I love what it represents, it just doesn't seem to suit my brewing!

Funnily enough Simon, writing my last post here got me thinking that I should re-visit the original figures where the 0.628 figure comes from. A few interesting things came up. I'll come back to your BeerSmith comments towards the end as but before that...

Is the BIABacus Formula Correct?

The original number, 0.62823, actually comes from a cross-breed of cold and hot numbers back in the very early days which then lead to The Calculator . Basically the following figures were collected...

1. Grain weight
2. Starting volume (cold)
3. Volume into Boil (Hot)

I got rid of some rounding inaccuracies and 0.62823 should actually be 0.63127. I'll change this in the BIABacus but it will make hardly any difference at all. Let's check the logic of the formula though.

The averages we collected to get the 0.63127 were...

1. 5983.5 grams
2. 40.05 L of ambient water used in the full volume mash (TWN)
3. 36.28 L volume into boil (VIB)

The current BIABacus formula gives...
(40.05-0.63127*5.9835)/0.9614 = 37.73 (should be 36.28)

So, this is wrong. We fix this by getting rid of the 0.9614...

(40.05-0.63127*5.9835) = 36.27 (cool)

I'll fix that in the next release. I have no idea when that error crept in as we had The Calculator, BeerSmith2 and The Calculator all agreeing in this area at one point. It's great that you asked the question as I haven't looked at that part in ages. .

Is the BeerSmith2 Formula Correct?

Firstly, remember that the BIABacus is the only software that actually considers the volume at mash temperature. See how in BeerSmith, 'Tot Mash Water' and 'Total Water Needed' are the same? But...

Mash volume is actually of no interest to us when we are talking about Volume Loss from Lauter. The only relevant thing in mash volume is "displacement" which as we saw in the last post, is different from "Volume Loss from Lauter".

Anyway, let's check BeerSmith's figures as best as we can. We'll assume that their TWN is at ambient. Here's the numbers from a BeerSmith recipe...

1. 6401 grams
2. 30.41 L of ambient water used in the full volume mash (TWN)
3. 26.5 L volume into boil (VIB)

Checking it against what the new BIABacus formula will be...
(30.4-0.63127*6.401) = 26.36 (Close enough. If they change their 0.6113 to the above, it will fix that.)

The good news is that thanks to your question, in future, you shouldn't be getting this problem in the BIABacus.

As a Matter of Interest

Brewers should not expect their figures in this are to agree with the BIABacus default. The default comes from a collection of many brewer's figures and there is a great variance among them. Some had numbers as high as 0.82 and as low as 0.34.

The main thing that will affect your Volume Loss from Lauter is your batch size. A small bag of grain is much easier to squeeze than say a double batch.

And, to Sum Up

The Volume Loss from Lauter for BIAB is 0.63127 litres/kg. Remember though that this is based on ambient temps. In traditional brews the loss is regarded as 1 L/kg but it is interesting to note that no one actually defines what temperature that 1 L is at. In BeerSmith and the BIABacus it is based on ambient and that's as good as anything really. This paragraph is not very good. Please see the quote in my next post below.

I'll try and get a pre-release out soon with that correction but there are some other things to tickle up so it might be a few days.

Good on you Simon ,
PP

PistolPatch wrote:
So, this is wrong. We fix this by getting rid of the 0.9614...

I'll fix that in the next release. I have no idea when that error crept in as we had The Calculator, BeerSmith2 and The Calculator all agreeing in this area at one point. It's great that you asked the question as I haven't looked at that part in ages. .


And, to Sum Up

The Volume Loss from Lauter for BIAB is 0.63127 litres/kg. Remember though that this is based on ambient temps. In traditional brews the loss is regarded as 1 L/kg but it is interesting to note that no one actually defines what temperature that 1 L is at. In BeerSmith and the BIABacus it is based on ambient and that's as good as anything really.

I'll try and get a pre-release out soon with that correction but there are some other things to tickle up so it might be a few days.

Good on you Simon ,
PP

Cheers PP. But just to clarify - you state that the Volume Loss from Lauter os 0.63127 L/kg - but that is only true for BIABacus, not all brews/brewers (which you also state)?

And you also say this is based on ambient temps - but it isn't is it? Ambient temp of Total Water Needed yes, but not Volume Into Boil? Which is why you removed the 0.9614 from the equation?

Just trying to get this straight in my head!

PITA isn't it?

On the first question though, the answer is yes. The BIABacus default (now 0.63127) is an average of a collection of different BIAB brewer's figures. Your result will vary from this depending on batch size, bag porosity, bag pull temp, time allowed to drain and amount of 'squeeze'.

On the second question, that bit of my post you have quoted on the ambient bit is not really written correctly. More accurately, the number relates to both the ambient volume and the volume at boiling, just as the original figures were. I'll give an example below.

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. (And, we definitely do not want to be thinking about mash volumes as they are irrelevant.)

BeerSmith does the same thing. For example, let's say you had a traditional brew (1L/kg loss) with zero mash tun deadspace, that had 8.5kgs of grain and a TWN of 58.5 L. You will find your VIB to equal 50 L.

So the proper answer I should have given in my last post (which I'll add an edit to) should have been something like...

The Volume Loss from Lauter for BIAB is 0.63127. This number should not be thought of as either an ambient or boiling volume figure. It should instead be viewed more as a factor.

Yeah, I think, that's a better way .

Another thing that makes this stuff hard to think through is that the formulas work backwards from Volume into Fermentor however our brain works forwards from Volume into Boil forwards.


PP

All good and all clear!