The formula to calculate the Plato (°P) from Specific Gravity (SG) is:
\[ Plato = (-1 \times 616.868) + (1111.14 \times SG) - (630.272 \times SG^2) + (135.997 \times SG^3) \]
Where:
Specific Gravity to Plato is a conversion used in brewing to measure the concentration of dissolved solids in a brewery wort. Plato degrees (°P) is a scale used to quantify the concentration of extract (mainly sugars derived from malt but also including other soluble material in wort) as a percentage by weight. Specific gravity, on the other hand, is a measure of the relative density of a liquid. Therefore, converting specific gravity to Plato degrees allows brewers to better understand the sugar content and potential alcohol content of the beer they are brewing.
Consider an example where:
Using the formula to calculate the Plato:
\[ Plato = (-1 \times 616.868) + (1111.14 \times 1.050) - (630.272 \times 1.050^2) + (135.997 \times 1.050^3) \]
Calculating step-by-step:
\[ Plato = -616.868 + 1166.697 - 695.785 + 150.497 = 12.39 \text{ °P} \]
This means that the Plato for this example is approximately 12.39 °P.