#### jcarson83

##### Well-Known Member

=1.313454-0.132674*t+2.057793*2.71828-3*t*2-2.627634*2.71828-6*t*3

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=1.313454-0.132674*t+2.057793*2.71828-3*t*2-2.627634*2.71828-6*t*3

=-2.52-0.0252*t+0.00112*t^2

The one I posted first is supposed to be accurate way above that.

/I think I finally beat HB99 with the smart a$$ comment.

jcarson83 said:

=1.313454-0.132674*t+2.057793*2.71828-3*t*2-2.627634*2.71828-6*t*3

Maybe you just typed the wrong thing, but that should be:

=1.313454-0.132674*t+2.057793*2.71828-3*t^2-2.627634*2.71828-6*t^3

where ^ means "to the power of"

Other than that, I really have no idea what the above means. What is t? Do you add the above result to what you actually read? I don't get it...

I have a maths degree, and I find something a bit strange about the two formulae. Are you sure that the 't' you use isn't measured from some temperature other than zero in one or both of the formulae?

The reason I ask is that it doesn't make sense to have completely different numbers in a formula that is supposed to be accurate to higher temps. The first few terms should be the same; it should just have some higher-order terms (terms proportional to t^4, t^5 etc.)

In fact, looking back at your original formula, it seems really strange as written. Perhaps try typing it out again? For example

-2.627634*2.71828-6*t^3 to me means:

-(2.627634*2.71828) - (6*t^3)

That seems weird. Why aren't all the constant terms just incorporated together?

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Ya got me there BS! Too much math in this post to get interested...I just add +1 or +2 and I'm done. Can't see all the fuss about large formula's when it's not necessary.Brewsmith said:

/I think I finally beat HB99 with the smart a$$ comment.

My chemistry is simple too! H2O is water and K9P comes from a dog.

Electronics? A Transistor is a nun who had a sex change...

Keep It Simple Smarta$$!!

Theres where I got the formula if anyone is interested.

C = ((1.313454 - (0.132674*F) + (0.00205779 * F^2) - (0.000002627634 * F^2)))

Where F = Temperature in degrees Fahrenheit.

C = Correction

So,

CG = C + (SG * 0.001)

Where,

CG = Specific Gravity corrected for temperature

C = Correction from above forumla

SG = Specific Gravity before temperature correction.

Here it is for everone using Degrees Centigrade:

C = ((1.313454 - (0.132674 * ((C * 1.8) + 32)) + (0.00205779 * (((C * 1.8) + 32))^2)) - (0.111112627634 * (((C * 1.8) + 32))^3)))

Then continue with the formula above formula for CG

Degrees F calculation

1) Use Cell B3 as your temperature (F) input.

2) Use Cell B5 as your SG input

3) Paste the following into Cell B7:

=1.313454 - (0.132674*B3) +( 0.002057793*(B3^2)) - (0.000002627634*(B3^3))

Paste the following into Cell B9:

=B5+(B7*0.001)

Cell B9 will contain your temperature corrected SG

For people using degrees centigrade, change the formula pasted into Cell B7 to the following:

=1.313454-(0.132674*((B3*1.8)+32))+(0.002057793*(((B3*1.8)+32)^2))-(0.000002627634*(((B3*1.8)+32)^3))

I'm sure that I could have reduced the formula down to something "prettier", but I really didn't feel like wasting time doing that. Besides, isn't that what's so nice about using Excel.

Cheers!

Disclaimer = It is possible that I made a transposition error when transferring this from Excel, so please check the Excel results against a table before using it.

Damn thanks man I was looking forever for this formula for my excel sheet. Thanks dude

Correction = 1.313454 - 0.132674*T + 2.057793e-3*T^2 - 2.627634e-6*T^3

but this assumes a hydrometer that is calibrated to 59F. if your hydrometer is calibrated to a different temp like 68F then i don't think this formula will not work. I've been looking for a formula that can be used for any calibration temp but so far haven't had much luck.

Correction = 1.313454 - 0.132674*T + 2.057793e-3*T^2 - 2.627634e-6*T^3

but this assumes a hydrometer that is calibrated to 59F. if your hydrometer is calibrated to a different temp like 68F then i don't think this formula will not work. I've been looking for a formula that can be used for any calibration temp but so far haven't had much luck.

This is exactly the problem I am running in to. I am trying to create a set of calculators for mobile devices, phones and such. I have a few already working but can not seem to find the formula for the hydrometer that can be adjusted to different calibrations temps.

If there is any body out there better at math than I am they might be able to modify the above formula to include the calibration temp variable.

Old fashioned hydrometers are calaborated at 15°C, but modern ones are collaborated at 20°C. The equation given before is for 15°C hydrometers. What makes it worse is that nowhere on line says which the string of numbers mean, or where they come from, so I can't develop my own 20°C equation.

This is the formula for Microsoft Excel:

Code:

`=A1*((1.00130346-0.000134722124*A2+0.00000204052596*A2^2-0.00000000232820948*A2^3)/(1.00130346-0.000134722124*A3+0.00000204052596*A3^2-0.00000000232820948*A3^3))`

Easily, the longest formula I've EVER typed into a spreadsheet. At least it works. I've tested the results against hydrometer correction charts in "How to Brew", "Brewing Quality Beers", and "Brewing Lager Beer".

There are some assumptions you will need to know for that formula to make any sense. Do this:

1) Create a new spreadsheet.

2) Cell A1 will hold your measured Specific Gravity reading. Type in 1.050 for testing purposes.

3) Cell A2 will hold your measured temperature. Type in 120 (I'm assuming Fahrenheit) for testing purposes.

4) Cell A3 will hold your hydrometer's calibration temperature. Mine is 70, but you can type in 59 since that's probably what yours is.

5) Copy and paste the above formula into cell A4.

If you used the values, 1.050 (measured s.g.), 120 (measured temp), and 59 (calibration), then you should see 1.0610 for your calibrated specific gravity reading.

I'm building a spreadsheet to help me plan my beers and I'm willing to give it away for free if anyone can tell me how to post it to this Forum.

Cheers,

Guido

I am thinking of building an open source home brewing and wine making calculator. What do you think?

That Beer Recipator link is awesome thanks

Code:

```
Function sgRatio(Temp As Double) As Double
sgRatio = 1.00130346 - 0.000134722124 * Temp + 0.00000204052596 * Temp ^ 2 - 2.32820948E-09 * Temp ^ 3
End Function
Function corSG(SG As Double, Temp As Double, CalT As Double) As Double
corSG = SG * (sgRatio(Temp) / sgRatio(CalT))
End Function
```

This is the formula for Microsoft Excel:

Code:`=A1*((1.00130346-0.000134722124*A2+0.00000204052596*A2^2-0.00000000232820948*A2^3)/(1.00130346-0.000134722124*A3+0.00000204052596*A3^2-0.00000000232820948*A3^3))`

Easily, the longest formula I've EVER typed into a spreadsheet. At least it works. I've tested the results against hydrometer correction charts in "How to Brew", "Brewing Quality Beers", and "Brewing Lager Beer".

There are some assumptions you will need to know for that formula to make any sense. Do this:

1) Create a new spreadsheet.

2) Cell A1 will hold your measured Specific Gravity reading. Type in 1.050 for testing purposes.

3) Cell A2 will hold your measured temperature. Type in 120 (I'm assuming Fahrenheit) for testing purposes.

4) Cell A3 will hold your hydrometer's calibration temperature. Mine is 70, but you can type in 59 since that's probably what yours is.

5) Copy and paste the above formula into cell A4.

If you used the values, 1.050 (measured s.g.), 120 (measured temp), and 59 (calibration), then you should see 1.0610 for your calibrated specific gravity reading.

I'm building a spreadsheet to help me plan my beers and I'm willing to give it away for free if anyone can tell me how to post it to this Forum.

Cheers,

Guido

Thanks for the formula Guido. Here is the same formula adjusted for temperate in Celsius:

Code:

`=A2*((1.00130346-0.000134722124*((B2* 9/5)+32)+0.00000204052596*((B2* 9/5)+32)^2-0.00000000232820948*((B2* 9/5)+32)^3)/(1.00130346-0.000134722124*((C2* 9/5)+32)+0.00000204052596*((C2* 9/5)+32)^2-0.00000000232820948*((C2* 9/5)+32)^3))`

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That seems weird. Why aren't all the constant terms just incorporated together?

2.71828 is the mathematical constant

I guess they aren't combined for clarity.

EDIT: Ignore this, I didn't see there was more than one page... oops!

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This is the formula for Microsoft Excel:

Code:`=A1*((1.00130346-0.000134722124*A2+0.00000204052596*A2^2-0.00000000232820948*A2^3)/(1.00130346-0.000134722124*A3+0.00000204052596*A3^2-0.00000000232820948*A3^3))`

Easily, the longest formula I've EVER typed into a spreadsheet. At least it works. I've tested the results against hydrometer correction charts in "How to Brew", "Brewing Quality Beers", and "Brewing Lager Beer".

There are some assumptions you will need to know for that formula to make any sense. Do this:

1) Create a new spreadsheet.

2) Cell A1 will hold your measured Specific Gravity reading. Type in 1.050 for testing purposes.

3) Cell A2 will hold your measured temperature. Type in 120 (I'm assuming Fahrenheit) for testing purposes.

4) Cell A3 will hold your hydrometer's calibration temperature. Mine is 70, but you can type in 59 since that's probably what yours is.

5) Copy and paste the above formula into cell A4.

If you used the values, 1.050 (measured s.g.), 120 (measured temp), and 59 (calibration), then you should see 1.0610 for your calibrated specific gravity reading.

I'm building a spreadsheet to help me plan my beers and I'm willing to give it away for free if anyone can tell me how to post it to this Forum.

Cheers,

Guido

Thank you so much for this. I didn't even consider that the exponents were getting formatted out when I was translating this formula. This was driving me nuts!

These hydrometers are laboratory grade and have an internal thermometer that give a correction factor of plus of minus tenth of degrees Plato. I just put the hydrometer in the beer, measure the gravity, and add or subtract the correction factor. I have measured beers accurately at up to 90 degrees F. Quick and easy, no math calculations necessary, I like quick and easy! I know that some online homebrew supply houses have SG hydrometers that have a correction thermometer in them that does the same thing, but they are not very accurate, from my experience. The ones I have are calibrated to an accuracy of less than 0.1 degrees Plato.

I know this is old, but does anyone have the source/publication for this formula?

This is the formula for Microsoft Excel:

Code:

Easily, the longest formula I've EVER typed into a spreadsheet. At least it works. I've tested the results against hydrometer correction charts in "How to Brew", "Brewing Quality Beers", and "Brewing Lager Beer".

There are some assumptions you will need to know for that formula to make any sense. Do this:

1) Create a new spreadsheet.

2) Cell A1 will hold your measured Specific Gravity reading. Type in 1.050 for testing purposes.

3) Cell A2 will hold your measured temperature. Type in 120 (I'm assuming Fahrenheit) for testing purposes.

4) Cell A3 will hold your hydrometer's calibration temperature. Mine is 70, but you can type in 59 since that's probably what yours is.

5) Copy and paste the above formula into cell A4.

If you used the values, 1.050 (measured s.g.), 120 (measured temp), and 59 (calibration), then you should see 1.0610 for your calibrated specific gravity reading.

I'm building a spreadsheet to help me plan my beers and I'm willing to give it away for free if anyone can tell me how to post it to this Forum.

Cheers,

Guido

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I know this isn't what you ask, but in 10°F of change from the calibration temperature, you are only going to be off by 0.001. Most of us really can't read our hydrometers within 0.002 on a good day.I know this is an old

I know this is old, but does anyone have the source/publication for this formula?

(never mind, I realize now I was reading what you quoted)

You could just take the SG of water at different temperatures and find out for yourself what your actual corrections should be.

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