From Christopher Lyons in HOMEBREW Digest #963 Mon 07 September 1992

Date: Fri, 4 Sep 92 11:25 EDT
From: "C. Lyons" <LYONS@adc1.adc.ray.com>
Subject: Follow-up on SG vs Temp.

Following up on the specific gravity of water as a
function of temperature....  The earlier equation was
based on data for 50F-to-105F.  Since the equation
was from a polynomial fit, it should not be trusted
for predicting SG outside this temperature range.
The data below was obtained using the "Handbook of
Chemistry and Physics (CRC)", and is valid for a
temperature range between 0 and 212F.

Temp (C)  Temp (F)  Density  Correction relative to 59F
- -------   --------  -------  --------------------------
0	   32	   0.99987	-0.74
3.98	   39.16   1.00000	-0.87
5	   41	   0.99999	-0.86
10	   50	   0.99973	-0.6
15	   59	   0.99913	0
18	   64.4	   0.99862	0.51
20	   68	   0.99823	0.9
25	   77	   0.99707	2.06
30	   86	   0.99567	3.46
35	   95	   0.99406	5.07
38	   100.4   0.99299	6.14
40	   104	   0.99224	6.89
45	   113	   0.99025	8.88
50	   122	   0.98807	11.06
55	   131	   0.98573	13.4
60	   140	   0.98324	15.89
65	   149	   0.98059	18.54
70	   158	   0.97781	21.32
75	   167	   0.97489	24.24
80	   176	   0.97183	27.3
85	   185	   0.96865	30.48
90	   194	   0.96534	33.79
95	   203	   0.96192	37.21
100	   212	   0.95838	40.75

The correction term was computed relative to
15C (59F).  It may be easily calculated relative
to any temperature.  A third order polynomial fit
to this data was also very good (R**2 = 0.999969):

Correction(@59F) = 
   1.313454 - 0.132674*T + 2.057793e-3*T**2 - 2.627634e-6*T**3

	where T is in degrees F.

This equation should be good for the entire temperature range
of interest :-)!


                              ... hope this helps,
				  Christopher Lyons
				  lyons@adc1.adc.ray.com