Math Problem and other issues re Water Chemistry Screen

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Math Problem and other issues re Water Chemistry Screen

Postby billvelek » Thu Nov 30, 2006 1:43 pm

Perhaps it is due to 'rounding', but my screen says that the difference between 12 and 8 is 3. If it is due to rounding, your display needs to take that into account, too, so that the math is shown correctly. I don't know if there are other math problems because this is the first and only comparison I've done since I've just started to play with this part. Here is how you can duplicate my results:

I created a 'test' water profile that just arbitrarily put values in as follows:
Ca = 1
Mg = 2
Na = 3
SO4 = 4
HCO3 = 5
Cl = 6
That gave me a Hardness of 11, Alk. of 4.76325, and Ph of 7.0

I then compared that to your loaded water profile for Pilsen, Czech., using 5 gallons of water, and I added to my 'Test' water .5 grams of Calcite.

You will note that the total Ca from my ingredients is 12, the amount of Ca in the water from Pilsen is 8, so the difference SHOULD be 4, but it shows 3. Also, there is a minus sign in front of the zero for the difference in Mg, and I presume you don't really want zero to have a negative value.

The next issue I have is with the Water Component Browser compared to your water chemistry screen; I'm not a chemist, so I don't know what 'HCO3' is, but it is listed on the water chemistry screen and has values for the profiles, but it is not listed as a component of any of the water additions in the Water Component Browser, so adjusting for that is going to be on a hit or miss basis. For example, Calcite contains '16' units of HCO3, so that info should be shown on the Water Component Browser; I can't imagine there is a reason to keep it off, so I'm sure this was just an oversight. I also assume that this is an important part of the water chemistry since, with the test that I ran, HCO3 is the only component where the indicator is yellow; that is how I discovered HCO3 is missing from the Component Browser -- I couldn't see which substance would be best to add.

The next issue is really more of a suggestion, and I don't know if it is even possible, or how easy or difficult it would be. Is there any way to have the program suggest the best combination of water additions to adjust the user's water to as close as possible to the target profile? Also, since I don't know how criticial water profiles can be, I assume that as long as the indicators are green, that we are close enough in the ball park, right?

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More questions re BTP using water chemistry

Postby billvelek » Thu Nov 30, 2006 3:43 pm

I have never been concerned with water chemistry in the past, and therefore don't really understand its impact on beer. However, I will presume that it has at least some detectable difference, otherwise why would anyone bother with it at all; the fact that this feature is part of BTP no doubt indicates that it has some effect. Now, as an experiment, I opened someone else's recipe; Jeff, you can find it on My Recipes -- it is 'Smoznewski'. I immediately printed out the recipe with its style comparison, analysis, and carbonation. I then went to 'Session | Water Chemistry' and selected a preloaded profile -- Burton on Trent -- which has rather dramatic 'chemistry' to it, and even the description on your 'Water Profile' says: "Uniquly hoppy pale ales because the hardness of the water accentuates the hop flavor". Now, I have to admit that I don't know if that statement also means that bitterness is affected. I would also imagine that conversion and extraction might be affected, too, but again I don't know. Anyway, after selecting my water and setting my quantity to 8 gallons to allow more than kettle volume of 6 gallons in the recipe, due to what is left in the mash tun, I clicked on 'Done'. I then examined the recipe, comparing it to my previous printout, and I can't see a single difference. Should that be so?

Actually, while the info is the same, the printout is different from the data on the screen. If you will merely open 'Smoznewski' and before making any adjusments at all, print it out. Then compare the Analysis section with your printout. I printed twice to be sure I didn't hit something by accident. I think you will find that Real Attenuation of the Terminal Extract is expressed as Plato on the screen, but the printout shows it as specific gravity. It is still correct in that 1.013 = 3.33P, but it is odd that the printout should make any changes, and also odd that the Apparent Terminal is still expressed in Plato.

Now, an even more important discrepancy in your program is that the results from your 'Calculator' (Attenuation Tab) does not match the results in the Analysis section of this recipe. But before I describe that, let me comment that I tried to find info on using the calculator in BTP User's Guide, to be sure I understood the results, etc., and there is not an entry for 'Calculators' to explain how to use them, etc. I checked the entire list of 'Contents' by opening every section, checked the 'Index', and also did a 'Search'; finally, I looked for "Attenuation" and that didn't clear up much because it doesn't mention the calculator at all. Anyway, the unaltered recipe here indicates the following data in the Analysis section:
.................... Apparent ..... Real
Orig.Extract:.... 10.49 P ..... 10.49 P
Attenuation: ... 84.4% ....... 68.2%
Terminal ...: ... 1.69 P ....... 3.33 P
% Alcohol ..: 3.66%ABW ..... 4.64%ABV

... BUT here is what the Calculator shows when I enter the same gravities (first, I'll use the Apparent gravities from above):
Original Gravity: 10.49 P
Terminal Gravity: 1.69 P
Apparent Atten.: 83.9% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 68.2%
% Alcohol by Vol: 4.7% -- NOTE THE DIFFERENCE (4.64%) even if rounded from above it should be 4.6%.
% Alcohol by Wt.: 3.7% -- (3.66% above) -- Probably due to rounding

(... and now using the REAL Gravities from above, which I would imagine are the more important):
Original Gravity: 10.49 P
Terminal Gravity: 3.33 P
Apparent Atten.: 68.3% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 55.5% -- NOTE THE DIFFERENCE (68.2% above)
% Alcohol by Vol: 3.8% -- NOTE THE DIFFERENCE (4.64% above)
% Alcohol by Wt.: 3.7% -- NOTE THE DIFFERENCE (3.66% above)

Now I presume that when using the 'Calculator', that we should be using the Apparent Gravities, above, but when comparing data as I've just done, I don't know what to use, and the User's Guide ought to explain that. Even still, there are some minor differences which I would think ought not to exist if your recipe analysis is using the same data and math as your calculator.

Finally, on the Analysis section of the session recipe, I can't really see the value of being able to change the "Serving" info, since nothing else changes on the page, and it is also unclear how much beer is used to determine the 'Weight' and 'Calories' for the alcohol, carbs, and protein. In other words, if I have "Serving" set to 12Fl.Oz. (common beer size in the U.S.), the nutritional value doesn't change if I change the "Serving" to a Pint. I think it should; now I don't know if those displayed values are for a 12oz. bottle or for a pint. I also don't see the purpose in being able to change "Serving" to 'barrel', 'dekaliters', etc., but I can just ignore that stuff.

Jeff, I know I'm probably overwhelming you with my posts, but I hope you appreciate the enormous amount of time that I'm spending trying to spot these problems for you and then be clear enough (I hope I am) in my posts for you to be able to use the info. This stuff obviously needs to be fixed when you can get to it, and I'm just trying to help you out.

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Re: More questions re BTP using water chemistry

Postby jeff » Thu Nov 30, 2006 5:08 pm

billvelek wrote:I have never been concerned with water chemistry in the past, and therefore don't really understand its impact on beer. However, I will presume that it has at least some detectable difference, otherwise why would anyone bother with it at all; the fact that this feature is part of BTP no doubt indicates that it has some effect. Now, as an experiment, I opened someone else's recipe; Jeff, you can find it on My Recipes -- it is 'Smoznewski'. I immediately printed out the recipe with its style comparison, analysis, and carbonation. I then went to 'Session | Water Chemistry' and selected a preloaded profile -- Burton on Trent -- which has rather dramatic 'chemistry' to it, and even the description on your 'Water Profile' says: "Uniquly hoppy pale ales because the hardness of the water accentuates the hop flavor". Now, I have to admit that I don't know if that statement also means that bitterness is affected. I would also imagine that conversion and extraction might be affected, too, but again I don't know. Anyway, after selecting my water and setting my quantity to 8 gallons to allow more than kettle volume of 6 gallons in the recipe, due to what is left in the mash tun, I clicked on 'Done'. I then examined the recipe, comparing it to my previous printout, and I can't see a single difference. Should that be so?


Water chemistry can be thought of as a utility like the Calculators window. Changing quantities there will have no effect on the quantities in the recipe. Also, there is a difference between perceived bitterness and lab measured bitterness. BTP can't predict how your taste buds will react to your recipe; it simply reports what concentration of iso-alpha acids you can roughly expect to see in your final product.

billvelek wrote:Now, an even more important discrepancy in your program is that the results from your 'Calculator' (Attenuation Tab) does not match the results in the Analysis section of this recipe. But before I describe that, let me comment that I tried to find info on using the calculator in BTP User's Guide, to be sure I understood the results, etc., and there is not an entry for 'Calculators' to explain how to use them, etc. I checked the entire list of 'Contents' by opening every section, checked the 'Index', and also did a 'Search'; finally, I looked for "Attenuation" and that didn't clear up much because it doesn't mention the calculator at all. Anyway, the unaltered recipe here indicates the following data in the Analysis section:
.................... Apparent ..... Real
Orig.Extract:.... 10.49 P ..... 10.49 P
Attenuation: ... 84.4% ....... 68.2%
Terminal ...: ... 1.69 P ....... 3.33 P
% Alcohol ..: 3.66%ABW ..... 4.64%ABV

... BUT here is what the Calculator shows when I enter the same gravities (first, I'll use the Apparent gravities from above):
Original Gravity: 10.49 P
Terminal Gravity: 1.69 P
Apparent Atten.: 83.9% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 68.2%
% Alcohol by Vol: 4.7% -- NOTE THE DIFFERENCE (4.64%) even if rounded from above it should be 4.6%.
% Alcohol by Wt.: 3.7% -- (3.66% above) -- Probably due to rounding

(... and now using the REAL Gravities from above, which I would imagine are the more important):
Original Gravity: 10.49 P
Terminal Gravity: 3.33 P
Apparent Atten.: 68.3% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 55.5% -- NOTE THE DIFFERENCE (68.2% above)
% Alcohol by Vol: 3.8% -- NOTE THE DIFFERENCE (4.64% above)
% Alcohol by Wt.: 3.7% -- NOTE THE DIFFERENCE (3.66% above)

Now I presume that when using the 'Calculator', that we should be using the Apparent Gravities, above, but when comparing data as I've just done, I don't know what to use, and the User's Guide ought to explain that.


Apparent attenuation does not take into account the lower density of the alcohol present in the measured samples. This is the attenuation value arrived at from your actual measured original and terminal gravities. Real attenuation is calculated based on the apparent values, but the apparent values are the ones you will read on the specific gravity scale on your hydrometer.

billvelek wrote:Even still, there are some minor differences which I would think ought not to exist if your recipe analysis is using the same data and math as your calculator.


BeerTools Pro uses internal values to perform all calculations. This means that if you see 10.49 BTP might be using an internal value of 10.48536711. Displaying values with full decimal equivalents becomes unwieldy for the user and the interface. Another thing to factor in is that BTP performs calculations in one set of units. This means that if data is entered in units other than the calculation unit, then BTP converts the value on the fly. This extra layer of calculation will diminish the precision of the operation.

I agree, though, that the User Guide is lacking a lot of stuff; and we intend to flesh it out more to make it more useful.

billvelek wrote:Finally, on the Analysis section of the session recipe, I can't really see the value of being able to change the "Serving" info, since nothing else changes on the page, and it is also unclear how much beer is used to determine the 'Weight' and 'Calories' for the alcohol, carbs, and protein. In other words, if I have "Serving" set to 12Fl.Oz. (common beer size in the U.S.), the nutritional value doesn't change if I change the "Serving" to a Pint. I think it should; now I don't know if those displayed values are for a 12oz. bottle or for a pint.


My copy shows a definite change in calorie information when i switch from 12 fl oz to 1 pint. This is not the case with your copy?

billvelek wrote:I also don't see the purpose in being able to change "Serving" to 'barrel', 'dekaliters', etc., but I can just ignore that stuff.


The "volume" units menu is a global control. The same units are listed in any instance of this control.

billvelek wrote:This stuff obviously needs to be fixed when you can get to it, and I'm just trying to help you out.


If something is broken, I will by all means fix it. Thanks for the feedback!
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Re: More questions re BTP using water chemistry

Postby billvelek » Thu Nov 30, 2006 5:18 pm

My copy shows a definite change in calorie information when i switch from 12 fl oz to 1 pint. This is not the case with your copy?
I'm on my way out in the POURING rain to work on my sewer line <sigh>, so I don't have time to digest your reply, but to answer quickly about the above, ... no, the calories don't change. I'm using BTP v.1.0.14 and WindowsXP, and for the referenced recipe -- "Smoznewski" -- my analysis shows "90.28 calories" regardless of whether my "Serving" is "12 Fl.Oz." or "Pints" or "Barrels". Now, maybe that is because I haven't changed the recipe, but I don't really see how that matters since the creator of the recipe might have been using pints, and I will bottle in 12 Oz. bottles -- I should still be able to recalculate the nutritional info. Hope that helps.

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Re: More questions re BTP using water chemistry

Postby jeff » Thu Nov 30, 2006 5:32 pm

billvelek wrote:my "Serving" is "12 Fl.Oz." or "Pints" or "Barrels". Now, maybe that is because I haven't changed the recipe, but I don't really see how that matters since the creator of the recipe might have been using pints, and I will bottle in 12 Oz. bottles -- I should still be able to recalculate the nutritional info. Hope that helps.


If you have 12 fl oz and switch to pints does the 12 change to 0.8? If you do notice the conversion occur, then no change in calories can be expected until you change to a different volume. Changing to unit in the menu just changes how the same volume is measured.

Units aside, what happens if you change 12 fl oz to 13 fl oz and hit enter?
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Re: More questions re BTP using water chemistry

Postby billvelek » Thu Nov 30, 2006 9:07 pm

jeff wrote:If you have 12 fl oz and switch to pints does the 12 change to 0.8? If you do notice the conversion occur, then no change in calories can be expected until you change to a different volume. Changing to unit in the menu just changes how the same volume is measured.

Units aside, what happens if you change 12 fl oz to 13 fl oz and hit enter?

Please forgive my stupidity. :oops: Yes, if I change 12 oz. = .8 pints to 1.0 pints, then, yes, the nutritional values change proportionately. Duhhh. I just figured that going from one unit to another was going to automatically change the nutritional values for that unit. In defense of my stupidity, however, wouldn't it be better to switch values automatically to whole units, i.e, 1 - 12 oz. serving, vs. 1 - pint, vs. 1 cup (8 oz.), etc.?

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Postby slothrob » Fri Dec 01, 2006 9:52 am

The convienience of this feature is when you have something in, say, gallons and you want to change it to quarts, it does the math for you. If you really wanted to have 1 qt instead of 1 gallon, you have to type it in, but that doesn't require breaking out a calculator to do the math.
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I think my approach is more logical, useful, and intuitive

Postby billvelek » Fri Dec 01, 2006 11:58 am

I guess I can see some minor convenience to do what you have indicated, because it automatically gives you equivalents -- but that's all it does automatically. So if you entered 5 gallons originally, and wanted to quickly know how many ounces are in 5 gallons, you just change the units to ounces, and voila ... but nutritional value remains the same. Does anyone really care how many grams and calories of alcohol, etc., are in a hektaliter or barrel, and does anyone care that 5 gallons of recipe 'X' contains 4,814 calories, and with a couple of mouse clicks we can automatically see that 20 quarts or 40 pints also contain 4,814 calories in the aggregate. No, I think nearly all of us want nutritional value for single, whole units that we are packaging in. Whenever I bottle a batch, I never know precisely how much I have, and I don't care; what I have is what I have, and I just prepare plenty of bottles, and sometimes I even package the same beer in different size bottles -- usually in 12oz. but many times I will have some empty pint bottles thrown in, too. So, I don't really see any convenience for me to go to a whole lot of trouble to measure my batch of beer before bottling so that I know that I have 4.68 gallons, and to then be able to quickly flip through and see that 4.68 gallons (which isn't a reasonable "Serving" size anyway) has 4,506 calories, and that it equals 18.7 Quarts = 37.4 Pints = 599 Oz., which ALL have 4,506 calories. Besides, for most conversions of fluid volumes (as opposed to nutritional value), most of us can quickly do that in our heads, as you've said. So it seems logical to me that the most convenient things should be things that are done automatically, and in this instance that means that switching serving sizes from quarts to pints to 12 oz. bottles ought to automatically display the nutritional value for a single bottle serving, accordingly. And I also think that that is the most intuitive, too, which is why I ran into some confusion in the first place. That's all I was trying to say. And Jeff, it would be nice and convenient if you would add to your serving size list "12 oz." in addition to the "ounces" that is listed, or at least cause ounces to default to 12, since whenever people are dealing with ounces, I think that '12' is the most common size. But that's no big deal, either, because we just need to go to the trouble of typing '12'.

Also, Jeff, what would be really neat is if you could include BOTH aspects described above, so that if anyone is interested in entering the 'Total Volume for Packaging' and the 'Serving Size', then BTP will display nutritional info for a single serving and also display the total number of servings (bottles needed) that is contained in that Total Volume. I think that would be more convenient and useful for most of us. But that is just polishing the program, in my opinion.

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Postby slothrob » Fri Dec 01, 2006 12:04 pm

Less useful in this part of the program, obviously, but I like this aspect and find it very useful in other parts of the program, e.g. grain weights and mash volumes. I believe Jeff said somewhere that the same bit of programing is used for all these fields.
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Postby billvelek » Fri Dec 01, 2006 12:38 pm

slothrob wrote:Less useful in this part of the program, obviously, but I like this aspect and find it very useful in other parts of the program, e.g. grain weights and mash volumes. I believe Jeff said somewhere that the same bit of programing is used for all these fields.
Well, if that's the case, then I'll have to agree with you that this needs to stay as is; however, I can't believe, after all of the more important issues are worked out, that this can't be improved without detracting or affecting other parts of the program. Might need it's own independent lines of code, but I'm sure it can be done. Of course, I'm just trying to give constructive criticism to help, in my opinion, polish the program. I want this to be a big success, because the more people who use this, the more recipes, etc. And speaking of recipes, I haven't checked them out much -- can't recall looking at them on BeerTools.com prior to buying this software, and only looked at three since getting BTP. I'm assuming that many of them are pretty old, as in original posts when BT.com was first created, which I'm sure was a long time before BTP was envisioned. Is all of the data there for use in BTP, such as mashing schedules? Also, is there any way to identify recipes that might have been used to win or place in beer competitions, or that are by certified beer judges, etc.,, versus some recipes that might not be very good at all. I noticed that there are sometimes comments for recipes, but it seems, from my quick look, that most have no comments, or comments are by the creator of the recipe. Just wondering how, if I find 100 IPA recipes, to identify the best ones. Any suggestions?

EDIT: Actually, I just visited BT.com and found that the featured recipe -- "Road Trippel" by Eric Armstrong -- is an award winner. So I guess I can start by looking for recipes by Eric. I guess it's just a matter of doing the right kind of searches. I know Jeff and company have other things to occupy them, but it would still be great if BTP would select perhaps just 2 or 3 of the best recipes in each category, and furnish them as part of the program download.

Thanks.

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Postby lathe » Fri Dec 01, 2006 1:40 pm

Bill,

There was a BeerTools Observer article on this very topic awhile back. It points you to a few recipes.

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Thanks; now a question and suggestion about download limits

Postby billvelek » Fri Dec 01, 2006 2:29 pm

Thanks, Lathe. That helps.

Can you tell me whether the "month" for recipe download limits is based on a member's monthly anniversary or is it calendar month? I'm guessing it is 'anniversary' since this is just the 1st day of the month and I've just hit my limit but only downloaded two recipes today. If it's a monthly 'anniversary', is it based on when a person registered with BeerTools.com (I have no earthly idea when that was or how to check), or is it based on when a person registered their BTP program (also don't know exactly when that was either)? In any event, my suggestion that I think would be handy for people is for the BTP 'Online' window to display the day of the month when the count will be reset. That way a user could tell at a glance that they have just a few days left to use up their limit -- if they are interested in collecting recipes.

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Re: Thanks; now a question and suggestion about download lim

Postby jeff » Fri Dec 01, 2006 2:33 pm

billvelek wrote:Thanks, Lathe. That helps.

Can you tell me whether the "month" for recipe download limits is based on a member's monthly anniversary or is it calendar month? I'm guessing it is 'anniversary' since this is just the 1st day of the month and I've just hit my limit but only downloaded two recipes today. If it's a monthly 'anniversary', is it based on when a person registered with BeerTools.com (I have no earthly idea when that was or how to check), or is it based on when a person registered their BTP program (also don't know exactly when that was either)? In any event, my suggestion that I think would be handy for people is for the BTP 'Online' window to display the day of the month when the count will be reset. That way a user could tell at a glance that they have just a few days left to use up their limit -- if they are interested in collecting recipes.

Cheers.

Bill Velek


It's based on the last 30 days of activity.
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Re: More questions re BTP using water chemistry

Postby billvelek » Fri Dec 15, 2006 3:08 am

I addressed this problem earlier, and you responded, but I think it needs a second look; relevant portions of my previous comments and your reply appear at the end of this post, following the line of asterisks. Using 10 pounds of 2-Row Brewers Malt for a Final Volume of 5.0 gallons, my recipe analysis tab displays the following for 'Apparent' attenuation:

O.G. = 13.06 P
Atten. = 75.0%
T.G. = 3.38 P
ABW = 4.08%
ABV = 5.2%

But using the BPT 'Calculator' -- '%Atten.' tab -- and entering the same O.G. and T.G. as just furnished by the 'Analysis', above, gives the following:

O.G. = 13.06 P -- manually entered
Atten. = 74.1% -- calculated, with a .9% difference from the analysis
T.G. = 3.38 P -- manually entered
ABW = 4.2% -- calculated, with a .18% difference in display, which is a .18/4.08=.044 ... over a 4% deviation from the analysis
ABV = 5.3% -- calculated, with a .1% difference from the analysis diisplay above.

Please note that if I enter just the O.G. and then enter the same 'Attenuation' of 75%, the differences are just as dramatic.

You explained this earlier (see your comments below), but it doesn't make a lot of sense to me that you would have BTP display data to an accuracy of one or two decimal places and yet have that much deviation. I'm not playing with a lot of different units here to have any 'layered' effect, in my opinion; I merely added 10 pounds of grain for a Final Volume of 5 gallons, and then entered into the 'calculator' the resulting gravities that were just provided by the analysis section. And it is difficult to see that this is a 'rounding' function either, since the ABW of 4.08% should round to 4.1% rather than the indicated 4.2%. At any rate, if they are not going to match, I'd at least like to know which one is correct.

Please forgive my persistence in this, and thanks for your patience with me.

Cheers, Bill Velek
*************** Previous Discussion **************
jeff wrote:
billvelek wrote:... snip ... the results from your 'Calculator' (Attenuation Tab) does not match the results in the Analysis section of this recipe. ... snip ... Anyway, the unaltered recipe here indicates the following data in the Analysis section:
.................... Apparent ..... Real
Orig.Extract:.... 10.49 P ..... 10.49 P
Attenuation: ... 84.4% ....... 68.2%
Terminal ...: ... 1.69 P ....... 3.33 P
% Alcohol ..: 3.66%ABW ..... 4.64%ABV

... BUT here is what the Calculator shows when I enter the same gravities (first, I'll use the Apparent gravities from above):
Original Gravity: 10.49 P
Terminal Gravity: 1.69 P
Apparent Atten.: 83.9% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 68.2%
% Alcohol by Vol: 4.7% -- NOTE THE DIFFERENCE (4.64%) even if rounded from above it should be 4.6%.
% Alcohol by Wt.: 3.7% -- (3.66% above) -- Probably due to rounding

(... and now using the REAL Gravities from above, which I would imagine are the more important):
Original Gravity: 10.49 P
Terminal Gravity: 3.33 P
Apparent Atten.: 68.3% -- NOTE THE DIFFERENCE (84.4% above)
Real Attenuation: 55.5% -- NOTE THE DIFFERENCE (68.2% above)
% Alcohol by Vol: 3.8% -- NOTE THE DIFFERENCE (4.64% above)
% Alcohol by Wt.: 3.7% -- NOTE THE DIFFERENCE (3.66% above)

... snip ...
SNIP
billvelek wrote:Even still, there are some minor differences which I would think ought not to exist if your recipe analysis is using the same data and math as your calculator.
BeerTools Pro uses internal values to perform all calculations. This means that if you see 10.49 BTP might be using an internal value of 10.48536711. Displaying values with full decimal equivalents becomes unwieldy for the user and the interface. Another thing to factor in is that BTP performs calculations in one set of units. This means that if data is entered in units other than the calculation unit, then BTP converts the value on the fly. This extra layer of calculation will diminish the precision of the operation. ... snip ...
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Postby slothrob » Fri Dec 15, 2006 11:36 am

No matter how far I push the rounding error for 13.06 sg and 3.38 tg (i.e., 13.0649 and 3.3750) I can't get an attenuation of 75%. The highest I can get it, while accounting for rounding errors, is 74.2%

The value 75% just seems wrong, somehow.
BTP v2.0.* Windows XP
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