# Seeking formula for adding sugar disolved in water to produce specific gravity

I have seen several tables, notably,

http://winemaking.jackkeller.net/hydrom.asp

http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm

But they all differ slightly. I'd like to test my hydrometer and refractometer with known gravities by adding sugar to a known volume of water (say 1 gallon for example) and taking measurements (like with no sugar, then the correct amount for 1.010/2.5Brix, etc), then increase the sugar and continue taking measurements, just to verify the readings. However, I can't seem to find where they are getting the numbers from for oz/gallon of sugar. Notably, Jack's table includes sugar added to water, which I believe would be the most useful, since I'll measure the water first, then add the sugar.

This post from adjelange has some more substantial detail, along with a "tl;dr:" that says basically: 1.046 for 1 lb in 1 gallon, and "The density does depend on the type of sugar but is not something you would be able to detect with a hydrometer."

(I found this by doing a google search for "sucrose gravity"; it was the first result.)

• Heh, nice. I will read through that and see if I can glean the formula. – Wyrmwood Sep 4 '13 at 15:45

OK, it appears the answer can be derived from the simple fact that "The [Plato] scale expresses the density as the percentage of sucrose by weight". By that token, the sugar content in oz is simply

8.3*16 * degrees plato or brix

To account for adding to water, you could say

(8.3*16)P%+(P%(8.3*16)*P%)

Obviously, the formula you use determine brix would play a large factor as well as the fact that the relationship between degrees Plato and specific gravity (SG) is not linear. I guess that's why Ball, Ack and Plato used tables...