#### Zul'jin

##### Well-Known Member

Thanks!

- Thread starter Zul'jin
- Start date

Thanks!

As for the specific formula, I am not sure what it is, but I suppose you could look at that pages source code.

Now, if you want to check your efficiency, then yes, most recipes are based around a 60-degree calibration.

Most my readings are taken at 68 degrees. That's my pitch temp and the ambient temp in my brewshop.

Code:

```
// Hydrometer correction formula
static double deltaSG(double TempC, double SG)
{ // hydrometer correction formula based on post by AJ DeLange
// in HBD 3701
double coeffic[][] = {{56.084, -0.17885, -0.13063}, // 0-4.99
{69.685, -1.367, -0.10621}, // 5 - 9.99
{77.782, -1.7288, -0.10822}, // 10 - 14.99
{87.895, -2.3601, -0.10285}, // 15 - 19.99
{97.052, -2.7729, -0.10596}}; // 20 - 24.99
double plato = SGToPlato(SG);
int coefficIndex=4;
if (plato < 20)
coefficIndex = 3;
else
if (plato < 15)
coefficIndex = 2;
if (plato < 10)
coefficIndex = 1;
if (plato < 5)
coefficIndex = 0;
double deltaSG = (coeffic[coefficIndex][0])
+ (coeffic[coefficIndex][1] * TempC)
+ (coeffic[coefficIndex][2] * TempC * TempC);
// changed + to - from original
double CorrectedSG = platoToSG(plato - (deltaSG/100));
return CorrectedSG;
}
public static double SGToPlato(double SG)
{ // function to convert a value in specific gravity as plato
// equation based on HBD#3204 post by AJ DeLange
double plato;
plato = -616.989 + 1111.488*SG - 630.606*SG*SG + 136.10305*SG*SG*SG;
return plato;
}
public static double platoToSG(double plato)
{ // function to convert a value in Plato to SG
// equation based on HBD#3723 post by AJ DeLange
double SG;
SG = 1.0000131 + 0.00386777*plato + 1.27447E-5*plato*plato + 6.34964E-8*plato*plato*plato;
return SG;
}
```

- Thread Starter
- #5

Wow! I think I heard a sonic boom from how fast those answers came in

With that conversion site I should be able to figure a formula, at least an approximation. I'll work on that later.

*And in comes JimC to crit my brain*

With that conversion site I should be able to figure a formula, at least an approximation. I'll work on that later.

Good to know as ABV% is what I want to figure out. I have the formula for that and ABW% too.BierMuncher: For tracking the ABV%, adjusting to a 60 degree reading is not that important if your final gravity reading will be taken at the same temperature as your original gravity.

SG = A + B*T + C*T^2

The lookup table has the dependency as to what your input gravity is, they fill in A, B, and C respectively based on degrees Plato, the comments to the right of the table show which ones go with which (or use the index ). The rest is convering to Specific Gravity it looks like or visa-versa.

yeah it takes the SG, puts in Plato, does the correction then back to SG...I think.

GT

What about at colder temperatures? 34?